PROF. OLAGO DANIEL OCHIENG

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The global sediment cycle is a fundamental feature of the Earth system, balancing competing factors such as orogeny, physical–chemical erosion and human action. In this Review, values of the magnitudes of several sources and sinks within the cycle are suggested, although the record remains fragmented with uncertainties. Between 1950 and 2010, humans have transformed the mobilization, transport and sequestration of sediment, to the point where human action now dominates these fluxes at the global scale. Human activities have increased fluvial sediment delivery by 215% while simultaneously decreasing the amount of fluvial sediment that reaches the ocean by 49%, and societal consumption of sediment over the same period has increased by more than 2,500%. Global warming is also substantially affecting the global sediment cycle through temperature impacts (sediment production and transport, sea ice cover, glacial ice ablation and loss of permafrost), precipitation changes, desertification and wind intensities, forest fire extent and intensity, and acceleration of sea-level rise. With progressive improvements in global digital datasets and modelling, we should be able to obtain a comprehensive picture of the impacts of human activities and climate warming.

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To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries.

Paleoanthropologists have long speculated about the role of environmental change in shaping human evolution in Africa. In recent years, drill cores of late Neogene lacustrine sedimentary rocks have yielded valuable high-resolution records of climatic and ecosystem change. Eastern African Rift sediments (primarily lake beds) provide an extraordinary range of data in close proximity to important fossil hominin and archaeological sites, allowing critical study of hypotheses that connect environmental history and hominin evolution. We review recent drill-core studies spanning the Plio?Pleistocene boundary (an interval of hominin diversification, including the earliest members of our genus Homo and the oldest stone tools), and the Mid?Upper Pleistocene (spanning the origin of Homo sapiens in Africa and our early technological and dispersal history). Proposed drilling of Africa's oldest lakes promises to extend such records back to the late Miocene. ?High-resolution paleoenvironmental records are critical for understanding external drivers of human evolution. ?African lake basin drill cores play a critical role in enhancing hominin paleoenvironmental records given their continuity and proximity to key paleoanthropological sites. ?The oldest African lakes have the potential to reveal a comprehensive paleoenvironmental context for the entire late Neogene history of hominin evolution. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.Paleoanthropologists have long speculated about the role of environmental change in shaping human evolution in Africa. In recent years, drill cores of late Neogene lacustrine sedimentary rocks have yielded valuable high-resolution records of climatic and ecosystem change. Eastern African Rift sediments (primarily lake beds) provide an extraordinary range of data in close proximity to important fossil hominin and archaeological sites, allowing critical study of hypotheses that connect environmental history and hominin evolution. We review recent drill-core studies spanning the Plio?Pleistocene boundary (an interval of hominin diversification, including the earliest members of our genus Homo and the oldest stone tools), and the Mid?Upper Pleistocene (spanning the origin of Homo sapiens in Africa and our early technological and dispersal history). Proposed drilling of Africa's oldest lakes promises to extend such records back to the late Miocene. ?High-resolution paleoenvironmental records are critical for understanding external drivers of human evolution. ?African lake basin drill cores play a critical role in enhancing hominin paleoenvironmental records given their continuity and proximity to key paleoanthropological sites. ?The oldest African lakes have the potential to reveal a comprehensive paleoenvironmental context for the entire late Neogene history of hominin evolution. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Transportation infrastructure, such as railways, roads and power lines, contribute to national and regional economic, social and cultural growth and integration. Kenya, with support from the Chinese government, is currently constructing a standard gauge railway (SGR) to support the country’s Vision 2030 development agenda. Although the actual land area affected by the SGR covers only a small proportion along the SGR corridor, a significant proportion of the area supports a wide range of ecologically fragile and important ecosystems in the country, with potential wider impacts. This study used a qualitative content analysis approach to gain an understanding and perceptions of stakeholders on the potential ecological impacts of the interactions between the SGR and the traversed ecological systems in Kenya. Three dominant themes emerged: 1) ecosystem degradation; 2) ecosystem fragmentation; and 3) ecosystem destruction. Ecosystem degradation was the most commonly cited impact at while ecosystem destruction was of the least concern and largely restricted to the physical SGR construction whereas the degradation and fragmentation have a much wider footprint. The construction and operation of the SGR degraded, fragmented and destroyed key ecosystems in the country including water towers, protected areas, community conservancies and wildlife dispersal areas. Therefore, we recommend that project proponents develop sustainable and ecologically sensitive measures to mitigate the key ecosystem impacts.

Tropical Africa experienced large changes in hydroclimatic conditions since the Last Glacial Maximum (LGM), ∼26.5 to 19 thousand years (ka or kyr) ago. The hydrogen isotopic composition of fossil leaf waxes (δDwax), assumed to record past variations in the hydrogen isotopic composition of precipitation (δDprecip), is increasingly being used to study past hydroclimatic change in Africa, and are commonly interpreted to reflect variation in the amount of precipitation through time (i.e., the amount effect). Although there are now many such δDprecip records from tropical Africa, there are few robust δDprecip records from easternmost equatorial Africa of sufficient length and resolution to evaluate the mechanisms governing hydroclimate variation during and since the LGM. We produced a new δDprecip record based on analyses of δDwax in sediment cores collected from Lake Rutundu, situated at an elevation of 3,078 meters above sea level (m asl) on Mt. Kenya. This record displays large variations in δDprecip corresponding with known climate events over the past 25 kyr, including D-enrichment during the Heinrich 1 stadial (H1) and the Younger Dryas (YD), and D-depletion during the Holocene portion of the African Humid Period (AHP). We also observe D-depletion during the LGM relative to the late Holocene, which, considering the amount effect, could be interpreted to imply that LGM climate conditions were wetter than today. However, because other hydroclimate proxies at this site indicate a drier LGM climate at Lake Rutundu, and since precipitation isotopes at this high-elevation site are likely influenced by different processes than at low elevations, we used a single-column Rayleigh distillation model to evaluate temperature and altitude-related effects on high-elevation δDprecip. This revealed that a change in the temperature lapse rate exerts strong control on δDprecip in this high-elevation setting, and that a steeper lapse rate could explain the observed D-depletion during the LGM at our site. Comparison of the Lake Rutundu δDprecip record with other leaf-wax based δDprecip records from East Africa indicates that changes in the meridional precipitation gradient associated with the mean annual position and intensity of the tropical rain belt, in turn driven by precessional insolation forcing, were likely a primary control on East African hydroclimate over the past 25 kyr, thereby contributing to overall regional drying during the LGM.

Tropical Africa experienced large changes in hydroclimatic conditions since the Last Glacial Maximum (LGM), ∼26.5 to 19 thousand years (ka or kyr) ago. The hydrogen isotopic composition of fossil leaf waxes (δDwax), assumed to record past variations in the hydrogen isotopic composition of precipitation (δDprecip), is increasingly being used to study past hydroclimatic change in Africa, and are commonly interpreted to reflect variation in the amount of precipitation through time (i.e., the amount effect). Although there are now many such δDprecip records from tropical Africa, there are few robust δDprecip records from easternmost equatorial Africa of sufficient length and resolution to evaluate the mechanisms governing hydroclimate variation during and since the LGM. We produced a new δDprecip record based on analyses of δDwax in sediment cores collected from Lake Rutundu, situated at an elevation of 3,078 meters above sea level (m asl) on Mt. Kenya. This record displays large variations in δDprecip corresponding with known climate events over the past 25 kyr, including D-enrichment during the Heinrich 1 stadial (H1) and the Younger Dryas (YD), and D-depletion during the Holocene portion of the African Humid Period (AHP). We also observe D-depletion during the LGM relative to the late Holocene, which, considering the amount effect, could be interpreted to imply that LGM climate conditions were wetter than today. However, because other hydroclimate proxies at this site indicate a drier LGM climate at Lake Rutundu, and since precipitation isotopes at this high-elevation site are likely influenced by different processes than at low elevations, we used a single-column Rayleigh distillation model to evaluate temperature and altitude-related effects on high-elevation δDprecip. This revealed that a change in the temperature lapse rate exerts strong control on δDprecip in this high-elevation setting, and that a steeper lapse rate could explain the observed D-depletion during the LGM at our site. Comparison of the Lake Rutundu δDprecip record with other leaf-wax based δDprecip records from East Africa indicates that changes in the meridional precipitation gradient associated with the mean annual position and intensity of the tropical rain belt, in turn driven by precessional insolation forcing, were likely a primary control on East African hydroclimate over the past 25 kyr, thereby contributing to overall regional drying during the LGM.

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The Maasai pastoralists inhabiting Kajiado County have been known for their rich cultural values which have sustained their livelihoods. However, these cultural practices are evolving under the swift development context with the private holding of land becoming more prevalent. Before these disturbances, customary land was available for the Maasai pastoralists to carry out traditional production systems. The disturbance in their social-cultural ways following land fragmentation has rendered their traditional governance system untenable. Moreover, the Maasai pastoralists have been dispossessed from their customary land and social institutions which have shaped their customs. Thus, concerns have been raised over the sustenance of pastoralism considering that the required resources are either unavailable or not enough. To address this gap, there was the need to understand cultural adjustments and their impacts on the Maasai pastoralists’ societal needs. The study employed a cross-sectional design which consisted of 195 Household survey questionnaires, 8 Focus Group Discussions and 18 Key Informant Interviews. The qualitative and quantitative data from the study were summarized and thematic perceptions generated. The results of this study revealed the uniqueness of the Maasai pastoralists’ traditional social structures. Also highlighted by the study was the erosion of the traditional social relations exposing the Maasai pastoralists to increasing vulnerability. These findings support the need for external support to supplement the traditional coping strategies to balance the ecological, social and economic systems of the Maasai pastoralists.

{In the age of climate change, the efficient allocation, distribution and use of water raises complex issues for water management, with far-reaching and often contentious consequences. As water becomes scarcer, water-related tensions are imminent on different scales. It is the interplay of these tensions with a number of socioeconomic, political, environmental and cultural factors that determine the probability of conflict. Lamu, found in the coastal part of Kenya, is a unique location in that access to water is already a major challenge. Combined with the negative impacts of climate change, and the ongoing large infrastructural development in the region, Lamu is on the verge of a water crisis. As such, there is a need for research into the context-specific factors that play a part in heightening the potential for water-related conflict amidst increasing water scarcity. The focus of this study was to identify and evaluate the context-specific factors that will amplify the potential for water-related conflict in Lamu. The findings suggest religion, migration, and poverty are factors that would heighten the potential for water-related conflict in the region amidst increasing water scarcity. The study recommends that these factors need to be addressed urgently and should be part of any water management mechanism in Lamu, in order to avoid water-related conflicts. Additionally, the findings imply that anticipating the stressors for water-related conflict in Lamu will play a significant role in managing conflict and facilitating negotiations over the region's water resources.}

Lake Nkunga is a crater Lake on the north eastern slopes of Mount Kenya that provides a record of catchment changes covering the last millennium. A multi proxy study was carried out on 89 cm of sediment core retrieved from 20 m near the lake shoreline. The mineralogy, magnetic mineralogy, organic and elemental geochemical proxies indicate a rejuvenating lake during the Medieval Climatic Anomaly with limited sediment supply and sustained by ground water. A progressive response to wetter conditions commences ca. 810 cal yr. BP with an increase in sediment influx that peaked at 500 cal yr. BP, a period that encompasses the start of the Little Ice Age (LIA). The establishment of the present-day maar conditions may have occurred during this period of the LIA. The lake has been relatively stable with declining terrestrial input from 290 cal yr. BP to present. The inferred changes in Lake Nkunga levels from deep to shallow phases are characterized by slow and muted response to both abrupt (e.g. Medieval Climate Anomaly) and sustained and prolonged climate shifts (e.g. Little Ice Age), reflecting the resilience of geolimnological and catchment processes in this lake and its watershed to climatic changes and human influence. This study provides new insights into the utility of biogeochemical proxies from nearshore lake cores in the equatorial east Africa highlands whose responses to extreme weather events are not well understood over the last 1000 years.

The advent of anthropogenic global warming and widespread modification of the climate, landscape and environment has brought humans to the fore as a formidable force of nature. The terrestrial and aquatic environment of the East African region is sensitive to a variety of global, regional and local stresses. The geological materials along East Africa coasts, lakes and peats are excellent archives of environmental and climatic changes. The study of their sedimentary records has contributed to our understanding of global environmental and ecosystem changes induced by anthropogenic activities associated with the “Anthropocene”, the proposed new geological epoch in Earth history. Humans have occupied East Africa for thousands of years, but until about 300 years ago, their impact on the environment was localized and transitory. The impacts intensified during the 19th century due to rapid population growth and extension and intensification of agriculture that was largely driven by colonists; during this period, the overprinting of natural environmental changes by humans is clear, marked by significant changes in sedimentation, sediment properties, and lake water quality as a consequence of land and water degradation and overexploitation of terrestrial and aquatic ecosystem goods and services. Related impacts include changes in terrestrial and aquatic ecosystems and associated biodiversity losses. There have been temporal and spatial lags in the changes, depending on locality, but there is a widespread convergence of these effects from the mid-1900s, support the Anthropocene Working Group's proposed date of 1950 as the start of the Anthropocene.

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Lodwar Municipality is one of the fastest-growing urban areas of Sub-Saharan Africa that depends mainly on groundwater for its municipal water supply. Most of the groundwater sources are located within the riparian zones of the Turkwel River. With limited understanding of its aquifers, the groundwater of Lodwar may be at risk of natural processes and anthropogenic activities. Statistical techniques and geochemical methods were applied to determine the aquifer hydrogeochemistry. Three distinct aquifers, which we collectively refer to as the Lodwar Alluvial Aquifer System, underlie Lodwar and its environs, the shallow alluvial, intermediate, and deep aquifers which are the main source of fresh water. A fourth, the shallow aquifer of the Turkana grit, is highly saline and with fluoride contamination. Just as the Turkwel River, the shallow alluvial aquifer (SAA) was dominated by Ca–HCO3 water type, while the TGSA was Na–Cl water type and became Na–HCO3 near the Holocene sediments. The intermediate aquifer (IA) was Na–HCO3water type. Pockets of Mg–HCO3 water occurred in the shallow alluvial and intermediate aquifers. The natural processes in the SAA include rock-water interaction, recharge by surface water, and oxidation reactions, while evaporation and dissolution are the major factors controlling the chemistry of the TGSA. Ion exchange, dilution, and dissolution are the major processes in the IA. Elevated levels of NO3− and SO42− during the wet season within the SAA and the IA reflects their vulnerability to pollution. Saline intrusion into the shallow and intermediate aquifers from the Turkana grit aquifers is likely to occur.

Grassland degradation and the concomitant loss of soil organic carbon is widespread in tropical arid and semi-arid regions of the world. Afforestation of degraded grassland, sometimes by using invasive alien trees, has been put forward as a legitimate climate change mitigation strategy. However, even in cases where tree encroachment of degraded grasslands leads to increased soil organic carbon, it may come at a high cost since the restoration of grassland-characteristic biodiversity and ecosystem services will be blocked. We assessed how invasion by Prosopis juliflora and restoration of degraded grasslands in a semi-arid region in Baringo, Kenya affected soil organic carbon, biodiversity and fodder availability. Thirty years of grassland restoration replenished soil organic carbon to 1 m depth at a rate of 1.4% per year and restored herbaceous biomass to levels of pristine grasslands, while plant biodiversity remained low. Invasion of degraded grasslands by P. juliflora increased soil organic carbon primarily in the upper 30 cm and suppressed herbaceous vegetation. We argue that, in contrast to encroachment by invasive alien trees, restoration of grasslands in tropical semi-arid regions can both serve as a measure for climate change mitigation and help restore key ecosystem services important for pastoralists and agro-pastoralist communities.

Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus considered extracellular (median 96.9%). ΔTLF was only significant in more urbanised study areas where TLF was greatest. Beneath Dakar, Senegal, ΔTLF was significantly correlated to total bacterial cells (ρs 0.51). No significant change in HLF following filtration across all data indicates these fluorophores are extracellular. Our results suggest that TLF and HLF are more mobile than faecal indicator bacteria and larger pathogens in groundwater, as the predominantly extracellular fluorophores are less prone to straining. Consequently, TLF/HLF are more precautionary indicators of microbial risks than faecal indicator bacteria in groundwater-derived drinking water.

Abstract
The African Great Lakes (AGL) have rich fisheries and are renowned “biodiversity hotspots”. Consequently the AGLand the ecosystem services they provide, underpin the welfare and livelihoods of over 50 million people across 10 countries. Despite the recognized importance of the AGL, these vital ecosystems and their livelihood support systems are threatened by numerous anthropogenic stressors at local, regional, and global scales. Past and continued efforts to address critical challenges on these lakes are often short-term, parochial, disparate, and uncoordinated resulting in a lack of comprehensive and comparable scientific data and inadequate resources to influence evidence-based policy. Over the past two decades, several international workshops, conferences and scientific publications have identified the need for collaboration, knowledge sharing, and harmonization of research and management as key elements to enhance conservation efforts in the AGL. In this commentary, we introduce the African Center for Aquatic Research and Education (ACARE), which aims to strengthen research and provide the scientific evidence needed to make informed decisions related to sustainable fisheries and aquatic resource management in the AGL. To do this, ACARE will administer a highly collaborative network of experts with three long-term goals: (1) strengthen global and regional research partnerships; (2) establish transboundary and inter-jurisdictional lake advisory groups; and (3) build capacity of freshwater scientists through experiential education and public engagement.

Keywords
African Great Lakes Collaborative networks Transboundary lake advisory groups, educationResearch partnerships

Kajiado County is predominantly inhabited by the Maasai nomadic pastoralists who rely on natural systems for their provisions and production needs. Traditionally, communal land management has been the norm in the area but that has evolved under the swift development context with the private holding of land becoming prevalent. The land-use transformation has curtailed the traditional seasonal movement of livestock and that has exposed the Maasai community to production risks which have contributed to the widespread food insecurity in the area. To address this gap, the study investigated land-use transformation in the area using Landsat 8, 4 and 5 datasets, where 1987, 2000 and 2015 epochs with a spatial resolution of 30*30m were sourced from www.glovis.usgs.org Remote sensing technology used to evaluate biophysical attributes showed changes in land-use patterns with the bare area, built-up area, cropland, forested land, grassland, riverine, shrubland, waterbody and wetland having undergone significant changes in their respective sizes. These land-use transformations have been compounded with the spread of invasive species to the point of threatening pastoralism. However, the successive governments have shown a marked disdain for resource use patterns. Thus, there is need for an all-inclusive land-use policies to inform adaptation and resilience planning in Kajiado County, Kenya.

Keywords

Natural Resource; Pastoralism; Biophysical Attributes, Land-Use Transformation; Remote Sensing; Masai Pastoralists

Smallholder dairy farmers occupy high potential areas of Kenya and are a source of manure, crops and milk. There is need to use other means of characterising smallholder dairy farmers as they mostly practice mixed farming. The objective of this paper is to use cluster analysis method to characterize the smallholder dairy farmers with added farmer and activity data variables. Clusters of 336 farmers in this study were derived using 28 key variables. This paper demonstrates how to conduct farmer assessments for climate change adaptation activities, climate smart technologies implementation using knowledge of key farmer variables and their distribution in the smallholder dairy farmers of Nandi County, Kenya. This paper demonstrates the importance of integrating agricultural information for smallholder dairy farmers to machine models to characterize the groups and observe the natural groupings. This allows for policy managers to know the key characteristics and how to use them in policy implementation especially in designing climate change adaptation programs factoring education and training of farmers as demonstrated in this paper that they are practicing many activities on their farms.

Key words: Cluster analysis, smallholder dairy farmers, farm utilisation, climate change adaptation.

The global quest for a sustainable bio-economy has brought to the fore importance of engaging agricultural systems in the production and in practice change. There have been issues limiting farmers from improving the practice of manure management as smart climate technology. The objective of this paper was to highlight the constraints, type, and valuation of manure types and information sources that smallholder dairy farmers find it useful to change Practices regarding manure management. In this present study, 336 smallholder dairy farmers were surveyed on various constraints the farmers faced and, on the type, and value of different manure types and information on manure management received by the farmers. The study used descriptive statistics for the variables and compared them using frequency tables. The key findings from this study would support information to stakeholders in inducing climate-smart manure management practices as a climate adaptation practice. The study highlights the type of information systems that determine areas for further investigation as drivers of practice change for smallholder dairy farmers. The paper focuses on these constraints and synthesizes them into factors that determine practice change on manure management by smallholder dairy farmers in order to improve manure management.

Key words: Manure management, agricultural information, smallholder dairy farmers, practice change,
information value.

Lodwar Municipality is one of the fastest-growing urban areas of Sub-Saharan Africa that depends mainly on groundwater for its municipal water supply. Most of the groundwater sources are located within the riparian zones of the Turkwel River. With limited understanding of its aquifers, the groundwater of Lodwar may be at risk of natural processes and anthropogenic activities. Statistical techniques and geochemical methods were applied to determine the aquifer hydrogeochemistry. Three distinct aquifers, which we collectively refer to as the Lodwar Alluvial Aquifer System, underlie Lodwar and its environs, the shallow alluvial, intermediate, and deep aquifers which are the main source of fresh water. A fourth, the shallow aquifer of the Turkana grit, is highly saline and with fluoride contamination. Just as the Turkwel River, the shallow alluvial aquifer (SAA) was dominated by Ca–HCO3 water type, while the TGSA was Na–Cl water type and became Na–HCO3 near the Holocene sediments. The intermediate aquifer (IA) was Na–HCO3water type. Pockets of Mg–HCO3 water occurred in the shallow alluvial and intermediate aquifers. The natural processes in the SAA include rock-water interaction, recharge by surface water, and oxidation reactions, while evaporation and dissolution are the major factors controlling the chemistry of the TGSA. Ion exchange, dilution, and dissolution are the major processes in the IA. Elevated levels of NO3− and SO42− during the wet season within the SAA and the IA reflects their vulnerability to pollution. Saline intrusion into the shallow and intermediate aquifers from the Turkana grit aquifers is likely to occur.

Access to water and sanitation remain a challenge in many developing countries, especially in pro-poor
urban informal settlements where socioeconomic livelihoods are generally low. The aim of this study was to characterise the water and sanitation facilities in the informal settlements of Kisumu City and to evaluate their effect on
community hygiene and health. The study focussed on the five urban informal settlements of Nyalenda A, Nyalenda
B, Manyatta A, Manyatta B and Obunga, and the three Peri-urban informal settlements of Kogony, Usoma and
Otonglo. Using descriptive techniques, the researcher surveyed 114 water sources and all sanitation facilities within
0-15m and 15-30m radii of the water sources. The findings revealed dominance of shallow wells and traditional pit
latrines as the primary water sources and sanitation facilities, respectively. Out of the water sources studied, 87.7%
(100) were shallow wells (mean depth 1.5 m), 9.6% (11) springs and 2.6% (3) boreholes. Most of these shallow
wells (83%) were within the urban informal settlements where uses range from washing and cleaning, cooking, and
even drinking (13.5%), despite the majority being unprotected. The analysis of the density of sanitation facilities
near the water points showed that 32.3% existed within a 15m radius of the nearest water sources, in violation of
the recommended safe distance of 30m. With an increased density of toilets near critical water sources and other
sanitary practices, public health is highly compromised.

Keywords : density, health, informal settlements, water-source, Sanitation technology.

Groundwater is the preferred alternative water source during times of shortages and in areas not served by piped water supplies. Pit latrines are the main sanitation facilities in Kisumu where sewerage extends over less than 20 per cent of the city. Pit latrines contribute to microbial contamination of shallow groundwater in Kisumu.

Ensuring water security to urban population in fragile environments through interlinked systems of groundwater abstraction, storage and distribution of sufficient quantity is challenging especially to urban utilities situated in arid and semi-arid regions. The purpose of this research was to evaluate water delivery challenges for water utilities in fragile environment in Kenya. A systematic analysis of availability from each supply sub-components from source to consumer was carried out through water audit and network analysis by employing water flow measurement equipments and through pump performance analysis and by employing continuity equation and Bernoulli’s principle to sections of the network. Results showed that water availability within a utility in such environments is contributed by seasonal variations between wet and dry affecting quantity at source, optimal design of supply infrastructure
in this case better matching of solar power with the pump, using standard pipes and on optimal operational strategies employed to reduce losses within the network. Based on these findings, we conclude that with clear understanding of each subcomponent’s contributions to entire water supply system and optimizing their design and operations, more people will be made water secure in all seasons in the fragile environments.

Keywords: Borehole • Availability • Water supply infrastructure

There is a gradual paradox shift from the utilization of surface water to groundwater in both urban and rural Kenya. This is because surface water is both diminishing in quantity due to climate variability and deteriorating in quality due to high levels of anthropogenic contamination. In the quest to attain the Sustainable Development Goal number 6 that aim at ensuring access to safe water by all by 2030, the Government of Kenya is encouraging the development of groundwater resources whose potential is enormous though it has not been quantified. The Inter-governmental Authority on Development (IGAD) supported this research on the shared Mt. Elgon trans-boundary aquifer between Kenya and Uganda aimed at understanding its dynamics. Mt. Elgon is a Tertiary age mountain that straddles the Kenya-Uganda border and has a trans-boundary aquifer. This study investigated the groundwater chemistry and its implication on water management and human health. Physico-chemical parameters of water that included electrical conductivity, pH, and temperature were measured in the field and the major cations and anions were measured at the Central Laboratories of the State Department for Water. Geological mapping and identification of sanitary risks were undertaken during the field work. The study revealed that the concentration of cations and anions in the groundwater varied spatially and temporally. Abundance of these ions were in the order Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ for most samples and HCO₃⁻ > Cl⁻ > SO₄²⁻ >NO₃⁻. Interpretation of hydro-chemical data suggests that calcium carbonate dissolution, halite dissolution, Ca/Na ion exchange and Mg/Na ion exchange are the major processes that control the ground-water chemistry. Chemical results indicate further that the groundwater is suitable for domestic use but is threatened by both anthropogenic and geological factors. Extensive use of fertilizer and the destruction of the catchment area coupled with low permeability and rock-water interactions in the metamorphic rock terrains are the main threats to groundwater quality in the region. A few water points had water with some ionic composition exceeding WHO and the local KEBS maximum limits for drinking water. Such water pose a risk to human health.

Based on a five-town case-study cohort in Kenya, a conceptual framework has been developed to enable the formulation of holistic and effective strategies that encompass the national aspirations and regional to global sustainability agendas, and which can be used to monitor progress in achieving set objectives. The approach is flexible, scalable and transferrable, so that it can be applied in different contexts and using different indicators, based upon the same construct. Insufficient technical knowledge of urban aquifers and their interplay with the wider social-ecological system constrains the development of holistic, effective and robust management systems to ensure their sustainability for intended uses. The objective was to consider governance and management solutions that could promote water security for urban towns in Kenya through the sustainable use of groundwater in the context of its complex hydrogeology, water access disparities, competing uses and future risks. The in force national and county water policies, strategies, and plans for the case study areas were critically reviewed. The status of aquifer knowledge, water access disparities, competing uses, and risks was evaluated from critical literature reviews and data compilation, fieldwork, and analysis of indicator datasets from the Kenya 2009 census. Key aquifers need urgent characterisation to reverse the current situation whereby development proceeds with insufficient aquifer knowledge. Private sector and public participation in management should be enhanced through decentralised management approaches. Water infrastructure and technologies should be fit-for-purpose in application and scale, and the pro-poor focus should be underpinned by appropriately focused management regimes.

In 2016–17 much of East Africa was affected by a severe drought which has been attributed to Indian Ocean Dipole and El Niño Southern Oscillation conditions. Extreme events such as this have immediate and knock-on effects on water availability for household, agricultural and industrial use. Groundwater resources can provide a buffer in times of drought, but may themselves be stressed by reduced recharge and increased usage, posing significant challenges to groundwater resource management. In the context of East Africa, groundwater management is also hampered by a lack of information on aquifer characteristics. With the aim of addressing this knowledge gap, this study shows the hydrogeological behaviour before and during La Niña 2016/17 drought in southern coastal Kenya on a groundwater system which sits within a geological structure which is representative of an important portion of the East African coast. Diverse hydrochemical and isotopic campaigns, as well as groundwater head variation measurements, were carried out to study the groundwater hydrodynamics and thus characterize the aquifer system under climatic conditions before and during the La Niña event. This information is complemented with an estimation of changes in local recharge since 2012 using local data sets. The main consequence of the drought was a 69% reduction of recharge compared to an average climatic year. There was reduced recharge during the first rainy season (April–June) and no recharge during the second wet season (October–December). There was a concurrent increase in seawater intrusion even during the wet season.

Sub-Saharan Africa (SSA; Fig. 1) refers to an area encompassing the countries in Africa that are fully, or partially, located south of the Sahara. The remaining African countries are generally referred to as belonging in North Africa. Although the socio-economic and hydrogeological conditions in SSA are diverse, they are sufficiently distinct (in general) from the conditions in North Africa to warrant being assessed separately—for example, high-yielding, high-storage, sedimentary aquifers are more common in North Africa than in SSA, while low-yielding, low-storage, basement aquifers are more widespread in SSA than in North Africa. The use of fossil groundwater is more typical in North Africa, while the use or renewable groundwater is more typical in SSA. Other hydrological characteristics associated with SSA include: groundwater resources that are generally under-utilized; lack of research and development that often prevents the optimal use of groundwater rather than over-development; and a heavy reliance by the rural and urban poor on shallow unconfined or semi-confined groundwater for potable water supplies, other domestic uses, and subsistence agriculture. Because of distinguishing characteristics such as these, there are good reasons for treating the hydrogeology of SSA as a whole, and separate from North Africa.

Abstract

The industrialization process taking place in Africa has led to an overall increase in groundwater abstraction in most countries in the continent. However, the lack of hydrogeological data, as in many developing countries, makes it difficult to properly manage groundwater systems. This study presents a real case study in which a combination of different hydrogeological tools together with different sources of information allow the assessment of how increased competition for water may be affecting groundwater systems by analysing the sustainability of new abstraction regimes under different real climatic condition (before, during and after La Niña 2016). The area where this approach has been applied is Kwale County (in Coastal Kenya) in a hydrogeological context representative of an important part of the east coast of the continent, where new mining and agriculture activities co-exist with tourism and local communities. The results show that the lack of aquifer systems data can be overcome, at least partly, by integrating different sources of information. Most of the time, water-reliant users collect specific hydrogeological information that can contribute to defining the overall hydrogeological system, since their own main purpose is to exploit the aquifer with the maximum productivity. Therefore, local community water usage, together with different stakeholder's knowledge and good corporate water management act as a catalyst for providing critical data, and allows the generation of credible models for future groundwater management and resource allocation. Furthermore, complementary but simple information sources such as in situ interviews, Google Earth, Trip Advisor and easy-to use analytical methods that can be applied in the African context as in many developing countries, and enables groundwater abstraction to be estimated and the sustainability of the aquifer system to be defined, allowing potential future risks to be assessed.

Abstract

Geomorphological and sedimentary records near the confluences of the Tana River and major tributaries draining the eastern slopes of Mt. Kenya and the Nyambeni Range, indicate impacts of Late Quaternary volcanic activity in their fluvial records. The main reconstructed event was triggered by a 366.9 ka basalt flow (40Ar/39Ar dated) which flowed along Kazita River from the Nyambeni Range blocking both Kazita River and Tana River near Kibuka Grand Falls, causing a temporary lake. Consequently, Tana River and Kazita River started to build volcanoclastic Gilbert type deltas. The preserved pro-delta sediments rich in trachytic pumice fragments display a mineralogical and age match with known Ithanguni trachytic tuffs, indicating delta build up right after a contemporary Ithanguni eruption. This trachytic eruption caused the deposition of lahars and fluvial volcaniclastic sediments in all river records draining the Eastern side of Mt. Kenya. The multiple lahars seem to be triggered by eruptions under glacial conditions (basalt age indicates MIS 10). The lava dammed lake was only short lived (estimated to have lasted only a few years to decades) and breached before a complete lake infill could occur. The current Kibuka Grand Falls can be viewed as the delayed incisional response of this lava dam breach, indicating that after >366.9 ka, Tana River is still responding and adjusting to this short-lived disruptive phase. The current Kazita River has re-incised adjacent to a MIS 4 basalt flow down into the crystalline Basement System rocks. The MIS 10 pre-volcanic sedimentary record indicates that more sediments were in the fluvial system during glacial conditions than during the interglacial conditions. An implication of our reconstruction is that the Late Quaternary fluvial record of Tana River is of only limited use to reconstruct uplift rates because reconstructed Quaternary incision rates are reflecting both volcanic disruptions as climate change trends of aridification and decreasing glaciation extents.

Safe water of adequate quantity, and dignified sanitation, is vital for the sustenance of a healthy and productive human population. In the recognition of this, the United Nations formulated the Sustainable Development Goal No. 6 to ensure access to safe water and sanitation by all by 2030. Actualization of this Goal requires information on the existing status of water resources and sanitation levels. Knowledge on contamination of groundwater is essential to prevent risks to human health. The objective of this study was to determine groundwater contamination in Kisumu, Kenya. A total of 275 water samples were collected from 22 sites within the informal settlements between December 2016 and December 2017. The samples were analysed for bacterial contamination and physical chemical quality. Thermal tolerant coliform bacteria enumeration was used as a proxy to bacteria contamination, and the pH, turbidity, dissolved oxygen, conductivity, salinity and temperature were used as physical chemical indicators of contamination. The results indicate that groundwater in Kisumu hosed coliform bacteria and therefore didn’t comply with contamination limits for domestic water proposed by WHO and local KEBS standards. The results further indicated that the levels of bacteriological contamination vary with water type, shallow well having the highest bacterial loads. The study concluded that there were potential risks to human health due to high content of coliform bacteria. The study attributed the contribution to pit latrines that were present in virtually all compounds. The pit latrines are located close to the water points. The study recommended the definition of minimum distance between the pit latrines and shallow wells to minimize contamination. The low income dwellers should be educated on simple ways of treating drinking water contaminated by microbial to minimize enteric infections.

There is a consensus that current trends in climate change may be due to increasing concentrations of greenhouse gases (predominantly methane and carbon dioxide) from anthropogenic emissions. Among measures proposed for curbing this increase is Carbon Capture and Sequestration (CCS) in geological media. CCS incorporates three technologies comprising; (a) carbon capture, (b) compression and transportation, and (c) injection into geological media. This paper focuses on CO2 injection into geological media and its applicability to the Lamu basin. Sedimentary basins, which host the geological formations suitable for subsurface CO2 storage, are ideal to varied extents determined by such factors as their tectonic settings. A (coarse) basin scale suitability assessment of the Lamu basin was undertaken using the following parameters; size and depth, tectonic and structural settings, seismicity, geothermal-hydrodynamic regimes, basin maturity (based on hydrocarbon well density) and economic resources. The assessed attributes are used to constrain GIS data, delineating possible CCS trap areas with the production of a preliminary map of potential trap areas. Also, a suitability matrix table is generated in comparison with analogous basins such as the Alberta basin in Canada. Following this assessment, the Lamu basin can be considered geologically suitable for geosequestration given its stable tectonic settings, good depth and size. However, the western flanks of the basin and the coastal strip are unsuitable due to shallowness, population and protected zones respectively.

Introduction
Sub-Saharan Africa (SSA; Fig. 1) refers to an area encompassing the countries in Africa that are fully, or partially, located south of the Sahara. The remaining African countries are generally referred to as belonging in North Africa. Although the socio-economic and hydrogeological conditions in SSA are diverse, they are sufficiently distinct (in general) from the conditions in North Africa to warrant being assessed separately—for example, high-yielding, high-storage, sedimentary aquifers are more common in North Africa than in SSA, while low-yielding, low-storage, basement aquifers are more widespread in SSA than in North Africa. The use of fossil groundwater is more typical in North Africa, while the use or renewable groundwater is more typical in SSA. Other hydrological characteristics associated with SSA include: groundwater resources that are generally under-utilized; lack of research and development that often prevents the optimal use of groundwater rather than over-development; and a heavy reliance by the rural and urban poor on shallow unconfined or semi-confined groundwater for potable water supplies, other domestic uses, and subsistence agriculture. Because of distinguishing characteristics such as these, there are good reasons for treating the hydrogeology of SSA as a whole, and separate from North Africa.

Abstract

An important aspect of the UN Framework Convention on Climate Change (UNFCCC), which aims to limit the increase in global temperature to 1.5 °C by 2050, has been the development of monitoring and evaluation plans that integrate climate change perspectives into new policies and programs for the protection and functioning of ecological systems. These include measures that enhance adaptive capacity, strengthen resilience and reduce vulnerability to climate change. Ecosystem change and the interaction of the different drivers of change in ecosystems have been studied at different temporal and spatial scales across different disciplines. However, the use of long temporal records documenting environmental and climatic change in understanding the impacts of the interacting drivers of change and planning sustainable use of resources is relatively new. We present examples of the use of palaeoecological data from East Africa in planning for the long-term sustainable use of natural resources by providing long-term historical perspectives on human–environment–societal–wildlife interactions and engagement with the biocultural heritage and societal evaluations of these spaces to achieve an increasingly diverse set of conservation, social and economic objectives. We link the Earth system processes whose associated boundaries can be directly related to sustainable development goals in our attempt to prevent unacceptable environmental change. The realisation that humans are having a significant impact on climate and landscapes means we now need to showcase the societal relevance of palaeoecological research and utilise its output especially in our efforts to remain within a safe operating space for humanity and ecosystems.

The sub-surface is used in most parts of Africa as a repository of human waste and as a source of groundwater through pit latrines and shallow wells respectively. The wells provide freshwater to millions of people in Africa who are either not connected to the piped water or have intermittent supplies. These shallow wells are hand dug and therefore are mostly less than 20 meters in depth. This same sub-surface environment is also used as a repository of human waste through pit latrines. The water points and the sanitation facilities are mostly located close to each other. This study aimed at appraising the groundwater and sanitation challenges based on a rapid survey, sampling, interviews, existing literature review and historical borehole data in Kisumu city, Kenya. Previous studies in the area have shown that the number of shallow wells, city buildings, density of unimproved pit latrines and sanitary risks have increased tremendously between 1999 and 2019. Most of the wells are shallow and therefore prone to contamination by pollutants. Fluoride and chloride content in most boreholes are above the recommended WHO maximum values and the local KEBS standards. The study confirmed that the main water and sanitation challenges in Kisumu are poor and deteriorating water quality, poor waste disposal management systems and poor sanitation services. There is need for the introduction of new and sustainable groundwater approaches supported by scientific models and involving all stakeholders. Current deficiencies in the provision of adequate water and dignified sanitation to the poor in Kisumu can be remedied through improved knowledge on shallow aquifer dynamics and innovative research. It was noted that apart from the donor agencies and multi-national NGOs, the private investors are unwilling to invest in water projects in Kisumu due in part to government legislation that constrains the cost that may be levied on water

Based on a five-town case-study cohort in Kenya, a conceptual framework has been developed to enable the formulation of holistic and effective strategies that encompass the national aspirations and regional to global sustainability agendas, and which can be used to monitor progress in achieving set objectives. The approach is flexible, scalable and transferrable, so that it can be applied in different contexts and using different indicators, based upon the same construct. Insufficient technical knowledge of urban aquifers and their interplay with the wider social-ecological system constrains the development of holistic, effective and robust management systems to ensure their sustainability for intended uses. The objective was to consider governance and management solutions that could promote water security for urban towns in Kenya through the sustainable use of groundwater in the context of its complex hydrogeology, water access disparities, competing uses and future risks. The in force national and county water policies, strategies, and plans for the case study areas were critically reviewed. The status of aquifer knowledge, water access disparities, competing uses, and risks was evaluated from critical literature reviews and data compilation, fieldwork, and analysis of indicator datasets from the Kenya 2009 census. Key aquifers need urgent characterisation to reverse the current situation whereby development proceeds with insufficient aquifer knowledge. Private sector and public participation in management should be enhanced through decentralised management approaches. Water infrastructure and technologies should be fit-for-purpose in application and scale, and the pro-poor focus should be underpinned by appropriately focused management regimes.

The El Niño event in 2015/2016 was one of the strongest since at least 1950. Through surveys and interviews with key informants, we found businesses in the capital cities of Zambia, Botswana and Kenya experienced major disruption to their activities from El Niño related hydroelectric load shedding, water supply disruption and flooding, respectively. Yet, during the 2015/2016 El Niño, fluctuations in precipitation were not extreme considering the strength of the El Niño event. Results therefore highlight that even fairly moderate precipitation anomalies can contribute to major disruption to economic activity. Addressing the risk of disruption – and supporting the private sector to adapt – is a development priority.

East African landscapes today are the result of the cumulative effects of climate and land-use change over millennial timescales. In this review, we compile archaeological and palaeoenvironmental data from East Africa to document land-cover change, and environmental, subsistence and land-use transitions, over the past 6000 years. Throughout East Africa there have been a series of relatively rapid and high-magnitude environmental shifts characterised by changing hydrological budgets during the mid- to late Holocene. For example, pronounced environmental shifts that manifested as a marked change in the rainfall amount or seasonality and subsequent hydrological budget throughout East Africa occurred around 4000, 800 and 300 radiocarbon years before present (yr BP). The past 6000 years have also seen numerous shifts in human interactions with East African ecologies. From the mid-Holocene, land use has both diversified and increased exponentially, this has been associated with the arrival of new subsistence systems, crops, migrants and technologies, all giving rise to a sequence of significant phases of land-cover change. The first large-scale human influences began to occur around 4000 yr BP, associated with the introduction of domesticated livestock and the expansion of pastoral communities. The first widespread and intensive forest clearances were associated with the arrival of iron-using early farming communities around 2500 yr BP, particularly in productive and easily-cleared mid-altitudinal areas. Extensive and pervasive land-cover change has been associated with population growth, immigration and movement of people. The expansion of trading routes between the interior and the coast, starting around 1300 years ago and intensifying in the eighteenth and nineteenth centuries CE, was one such process. These caravan routes possibly acted as conduits for spreading New World crops such as maize (Zea mays), tobacco (Nicotiana spp.) and tomatoes (Solanum lycopersicum), although the processes and timings of their introductions remains poorly documented. The introduction of southeast Asian domesticates, especially banana (Musa spp.), rice (Oryza spp.), taro (Colocasia esculenta), and chicken (Gallus gallus), via transoceanic biological transfers around and across the Indian Ocean, from at least around 1300 yr BP, and potentially significantly earlier, also had profound social and ecological consequences across parts of the region.

Through an interdisciplinary synthesis of information and metadatasets, we explore the different drivers and directions of changes in land-cover, and the associated environmental histories and interactions with various cultures, technologies, and subsistence strategies through time and across space in East Africa. This review suggests topics for targeted future research that focus on areas and/or time periods where our understanding of the interactions between people, the environment and land-cover change are most contentious and/or poorly resolved. The review also offers a perspective on how knowledge of regional land-use change can be used to inform and provide perspectives on contemporary issues such as climate and ecosystem change models, conservation strategies, and the achievement of nature-based solutions for development purposes.

The Maasai pastoralists have in the past decade experienced disruptions as precipitation season shifts. These shifts have adversely affected their economies and livelihoods. Moreover, they have been losing up to 30 % of their herd annually to drought related disasters, yet the locals’ capacity on climate pattern shifts is inadequate. To address this gap, a study focused on Kajiado County due to its harboring large of livestock. The study aimed at determining the historical precipitation characteristics. To achieve this, the study utilized Climate Hazards group Infra-Red Precipitation with Stations data set (CHIRPS) for the period 1983-2014 for each of the five sub-counties within Kajiado County. The key findings, encompassed: declining trend in the average annual precipitation; shifting from the usual bi-modal rainfall seasons with March to May (MAM) experiencing worst failure compared to October to December (OND) and the shortening of the famine cycles.

Study region

the Turkwel river basin, Kenya experiences a high level of water scarcity due to its arid climate, high rainfall variability and rapidly growing water demand.
Study focus

Climate change, variability and rapid growth in water demand pose significant challenges to current and future water resources planning and allocation worldwide. In this paper a novel decision-scaling approach was applied to model the response of the Turkwel river basin’s water resources system to growing demand and climate stressors. A climate response surface was constructed by combining a water resource system model, climate data, and a range of water demand scenarios.
New hydrological insights

The results show that climate variability and increased water demand are each important drivers of water scarcity in the basin. Increases in water demand due to expanded irrigation strongly influences on the resilience of the basin’s water resource system to droughts caused by the global climate variability. The climate response surface offers a visual and flexible tool for decision-makers to understand the ways in which the system responds to climate variability and development scenarios. Policy decisions to accelerate water-dependent development and poverty reduction in arid and semi-arid lands that are characterised by rapid demographic, political and economic change in the short- to medium term have to promote low-regrets approaches that incorporate longer-term climate uncertainty.

The 2015/2016 El Niño has been classified as one of the three most severe on record. El Niño teleconnections are commonly associated with droughts in southern Africa and high precipitation in eastern Africa. Despite their relatively frequent occurrence, evidence for their hydrological effects and impacts beyond agriculture is limited. We examine the hydrological response and impact pathways of the 2015/2016 El Niño in eastern and southern Africa, focusing on Botswana, Kenya, and Zambia. We use in situ and remotely sensed time series of precipitation, river flow, and lake levels complemented by qualitative insights from interviews with key organizations in each country about awareness, impacts, and responses. Our results show that drought conditions prevailed in large parts of southern Africa, reducing runoff and contributing to unusually low lake levels in Botswana and Zambia. Key informants characterized this El Niño through record high temperatures and water supply disruption in Botswana and through hydroelectric load shedding in Zambia. Warnings of flood risk in Kenya were pronounced, but the El Niño teleconnection did not materialize as expected in 2015/2016. Extreme precipitation was limited and caused localized impacts. The hydrological impacts in southern Africa were severe and complex, strongly exacerbated by dry antecedent conditions, recent changes in exposure and sensitivity and management decisions. Improved understanding of hydrological responses and the complexity of differing impact pathways can support design of more adaptive, region‐specific management strategies.

Anopheles gambiae s.l. (Diptera: Culicidae) is responsible for the transmission of the devastating Plasmodium falciparum (Haemosporida: Plasmodiidae) strain of malaria in Africa. This study investigated the relationship between climate and environmental conditions and An. gambiae s.l. larvae abundance and modelled the larval distribution of this species in Baringo County, Kenya. Mosquito larvae were collected using a 350-mL dipper and a pipette once per month from December 2015 to December 2016. A random forest algorithm was used to generate vegetation cover classes. A negative binomial regression was used to model the association between remotely sensed climate (rainfall and temperature) and environmental (vegetation cover, vegetation health, topographic wetness and slope) factors and An. gambiae s.l. for December 2015. Anopheles gambiae s.l. was significantly more frequent in the riverine zone (P < 0.05, r = 0.59) compared with the lowland zone. Rainfall (b = 6.22, P < 0.001), slope (b = - 4.81, P = 0.012) and vegetation health (b = - 5.60, P = 0.038) significantly influenced the distribution of An. gambiae s.l. larvae. High An. gambiae s.l. abundance was associated with cropland and wetland environments. Effective malaria control will require zone-specific interventions such as a focused dry season vector control strategy in the riverine zone.

Abstract

The Marsabit Forest Reserve (MFR), a green island in an arid environmental setting, generates multiple ecosystem goods and services (ES) to the local community critical for their livelihoods. The forest has been experiencing substantial land conversion for town expansion, agriculture production and settlements threatening long-term ES provision. Sustaining the forest ES under increasing anthropogenic pressures is one of the great challenges of the Marsabit forest community. We used focus group discussions in the thirteen locations around the forest and individual key informant's interviews in the identification of drivers of change and their potential impacts on ES in MFR. We used the scenario development process (SDP) in coming up with four divergent but plausible exploratory scenarios. The study established that the main ES provided by the forest was, water, fuelwood, forage (dry season grazing resource), medicinal plants and timber for construction. Stakeholders identified population pressure, unsustainable utilisation of forest resources, institutional barriers to effective resource management, land use and climate change as the main drivers impacting ES provision in the forest. Land use change and climate change were considered the most significant drivers yet the most uncertain in the future impacting ES provision in the MFR. The SDP identified four alternative future scenarios for the MFR by the year 2044 with the Marsabit we want scenario identified as the most desirable future for the sustainable supply of ES with adequate adaptation to observed changes. Stakeholders came up with a joint action plan implementation matrix for the identified scenario while mitigating the negative aspects of the alternative scenarios. The results support the need for participatory land use planning that takes into to account the growing threat of climate change to natural forest systems.

Abstract

This study presents past and projected temporal changes in mean temperature and rainfall around the Marsabit Forest Reserve (MFR), a sub-humid montane forest in Kenya. Rainfall data for the period 1961–2014 and temperature data for the period 1972–2011 were acquired from the Marsabit meteorological station. Future projections (2006–2100) were based on data from five models that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) under Representative Concentration Pathways (RCPs) 4.5 and 8.5. Climate simulations for the 2071–2100 period were compared to the 1961–1990 IPCC baseline period to establish significant change. The MFR recorded a mean rainfall of 784 mm which declined annually at a rate of 6 mm over the period of the study. The long rains (March–May) recorded a mean of 379 mm and decreased annually by 10 mm while the short rains (October–December) recorded a mean of 269 mm and decreased annually by 2 mm between 1961 and 2014, with no statistically significant trend (p > 0.05).

The model ensemble reproduced the MFR bimodal rainfall pattern, but overestimated the short rains at 333 mm, compared to the actual mean of 269 mm, and underestimated the long rains at 331 mm, compared to the actual mean of 379 mm. The model ensemble simulated a historical mean rainfall of 651 mm compared to the actual mean of 784 mm. Annual rainfall is projected to increase under both scenarios with higher increases during the OND season compared to the MAM season and under RCP8.5 than under RCP4.5. The mean rainfall in the baseline year was 859 mm while the mean rainfall in the projection period for the RCP4.5 and RCP8.5 scenarios is expected to be 1022 (+19%) and 1105 (+28.7%) mm, respectively; significant enough to be characterized as climate change.

Temperatures are projected to increase at a rate of 0.2 °C and 0.5 °C per decade under RCP4.5 and RCP8.5, respectively. Between 2071 and 2100, the MFR is projected to have warmed by between 1.2–1.7 °C and 3.2–4.8 °C under RCP4.5 and RCP8.5, respectively. Extreme rainfall events are projected to increase under the RCP4.5 scenario (severe wetting 13.1%, severe drying 3%) and the RCP8.5 scenario (severe wetting 20.1%, severe drying 3%) compared to the baseline period (severe wetting 6.1%). Our results conform to the ‘East African climate paradox’, where the observed rainfall trends were declining compared to the scenario simulations projecting a wetting anomaly as local temperatures rise. Further studies to better understand the cause of the poor rainfall simulation in the general circulation models (GCMs) in the MFR and the larger East African region will be necessary.

Climate change and variability is bound to impact Smallholder Dairy Farming Systems as a result of overreliance on rainfed fodder production; yet climate models project increased frequencies of droughts that have a bearing on the Length of Growing Period. Similarly higher environmental temperatures are partly attributed to biome-range shifts, implying a likelihood of emerging and re-emergence of livestock and fodder diseases and pests. Nonetheless not much is documented of perceptions and adaptation strategies employed by Smallholder Dairy Farming Systems geared towards resilience to climatie shocks. By employing a mixed method approach that included household surveys, focused group discussions and statistical data analysis using SPSS package, this study aimed to bridge some of the existing gaps in adaptation strategies on Smallholder Dairy Farming Systems in Siaya Sub-County of Western Kenya. Survey results obtained from 100 households and Focused Group Discussions revealed that the climate of the study location was perceived to have changed, with droughts singled out as the most frequent. These perceptions were consistent with long-term climate data analysis which affirmed that all seasons, i.e. MAM, JJA, and DJF with the exception of SON showed longterm drying trends. Similarly, environmental temperature showed upward trends in both maximum and minimum temperatures that were perceived to be the cause of proliferation of noxious weeds previously associated with hotter areas of the Sub-County. Typologies of adaptation strategies used in the study showed that adaptation options were limited since these were viewed through a narrow lens of disease control by regular spraying and maize stovers as supplementary livestock feed during fodder dearth periods. This study recommends that besides awareness creation of adverse impacts of climate change and variability, facilitation for ease of access to technologies that ameliorate its adverse effects ought to be put in place. Additionally, empirical studies on consequences of biome range shifts on pasture and fodder productivity, and future possible impacts of diseases on Bos taurus breeds associated with climate change and variability should be undertaken.

The quantification of carbon stocks is vital for decision making in forest management, carbon stock change assessment and scientific applications. We applied the land degradation surveillance framework (LDSF) method with a sentinel site of (10 km × 10 km) to assess carbon stock levels and tree diversity in the Marsabit Forest Reserve (MFR). The above ground (ABG) carbon stock was estimated at 12.42 t/ha, while soil organic carbon (SOC) was 12.51 t/ha, with SOC densities increasing with increasing depth. The mean ABG carbon and SOC densities were higher in the least disturbed strata than the disturbed strata. The estimated ABG carbon and SOC stocks were significantly lower than the range observed in a typical dry tropical forest. Twenty-one tree species were recorded belonging to twelve families with the disturbed areas recording nine tree species while the least disturbed recording twelve species. Rubiaceae and Rutaceae were the richest families with four species each while Boraginaceae, Capparaceae, Flacourtiaceae, Tiliaceae, Violaceae, and Ochnaceae the least frequent with one species each. The most common tree species were, Croton megalocarpus, Drypetes gerrardii, Ochna insculpta, Strychnos henningsii and Vangueria madagascariensis. The forest recorded a basal diameter of 14.09 ± 12.15 cm, basal area of 0.016 m 2/ha with a mean height of 8.69 m. The basal size class distribution declined monotonically indicative of a stable population. Livestock grazing, selective logging, and firewood collection were the primary forms of anthropogenic activities recorded in the MFR despite the moratorium imposed on consumptive utilisation of forest products by the Marsabit County security committee. The Pearson correlation coefficient returned an inverse relationship between forest disturbance with SOC and ABG carbon in the disturbed strata suggesting that anthropogenic activities reduced carbon stocks in the MFR. Concerted efforts to mitigate anthropogenic impacts on the MFR could significantly increase its terrestrial carbon sequestration potential and the provision of critical ecosystem goods and services.

The research study evaluated the reliability of Indigenous Traditional Knowledge (ITK) and conventional weather forecasts in the face of climate change and variability in Baringo County, Kenya. Systematic sampling technique was applied in drawing a sample size of 454 pastoralists and agro-pastoralists interviewed. Majority (68%) of the respondents have not been aware of blend/mixture of ITK and scientific forecasting techniques. Majority (78% ,77 %,74%, 61%,73%,73% and 71%) of the respondents perceived that conventional weather forecast approach is reliable on predicting short-rains season, long-rain season, rainfall intensity, landslide, thunder storm, expected rainfall onset and cessation, and El-Nino respectively. The majority (71%, 69%, 75% and 64%) of the pastoralists and agro-pastoralists professed that ITK weather forecast approach is reliable on predicting floods, seasonal rain distribution, temperatures and La-Nina respectively. None of the two weather forecasts approaches could exhaustively forecast the climate/weather events alone. The integration of the two approaches is ultimate for effective reliability.

The global increase in vector borne diseases has been linked to climate change. Seasonal vegetation changes are known to influence disease vector population. However, the relationship is more theoretical than quantitatively defined. There is a growing demand for understanding and prediction of climate sensitive vector borne disease risks especially in regions where meteorological data are lacking. This study aimed at analyzing and quantitatively assessing the seasonal and year-to-year association between climatic factors (rainfall and temperature) and vegetation cover, and its implications for malaria risks in Baringo County, Kenya. Remotely sensed temperature, rainfall, and vegetation data for the period 2004–2015 were used. Poisson regression was used to model the association between malaria cases and climatic and environmental factors for the period 2009–2012, this being the period for which all datasets overlapped. A strong positive relationship was observed between the Normalized Difference Vegetation Index (NDVI) and monthly total precipitation. There was a strong negative relationship between NDVI and minimum temperature. The total monthly rainfall (between 94 -181mm), average monthly minimum temperatures (between 16–21°C) and mean monthly NDVI values lower than 0.35 were significantly associated with malaria incidence rates. Results suggests that a combination of climatic and vegetation greenness thresholds need to be met for malaria incidence to be significantly increased in the county. Planning for malaria control can therefore be enhanced by incorporating these factors in malaria risk mapping.

The Maasai pastoralists have in the last decade experienced disruptions in their economies and livelihoods following climate shifts. For instance, they have been losing up to 30 % of their herd annually to drought related disasters, yet information on the various land uses is still fragmented. This has been worsened by the shortening famine cycles which has impacted pastoral livelihood system as they highly depend on natural resource. Yet, these key resources have been dwindling over the past 30 years compromising their ability to meet basic need such as food. To address this gap, the study focused on long term evaluation of land use. The study’s objective was to determine land use transformations and their impacts particularly on the pastoral livelihood system.

Background

The decline in global malaria cases is attributed to intensified utilization of primary vector control interventions and artemisinin-based combination therapies (ACTs). These strategies are inadequate in many rural areas, thus adopting locally appropriate integrated malaria control strategies is imperative in these heterogeneous settings. This study aimed at investigating trends and local knowledge on malaria and to develop a framework for malaria control for communities in Baringo, Kenya.

Methods

Clinical malaria cases obtained from four health facilities in the riverine and lowland zones were used to analyse malaria trends for the 2005–2014 period. A mixed method approach integrating eight focus group discussions, 12 key informant interviews, 300 survey questionnaires and two stakeholders’ consultative forums were used to assess local knowledge on malaria risk and develop a framework for malaria reduction.

Results

Malaria cases increased significantly during the 2005–2014 period (tau = 0.352; p < 0.001) in the riverine zone. March, April, May, June and October showed significant increases compared to other months. Misconceptions about the cause and mode of malaria transmission existed. Gender-segregated outdoor occupation such as social drinking, farm activities, herding, and circumcision events increased the risk of mosquito bites. A positive relationship occurred between education level and opinion on exposure to malaria risk after dusk (χ2 = 2.70, p < 0.05). There was over-reliance on bed nets, yet only 68% (204/300) of respondents owned at least one net. Complementary malaria control measures were under-utilized, with 90% of respondents denying having used either sprays, repellents or burnt cow dung or plant leaves over the last one year before the study was conducted. Baraza, radios, and mobile phone messages were identified as effective media for malaria information exchange. Supplementary strategies identified included unblocking canals, clearing Prosopis bushes, and use of community volunteers and school clubs to promote social behaviour change.

Conclusions

The knowledge gap on malaria transmission should be addressed to minimize the impacts and enhance uptake of appropriate malaria management mechanisms. Implementing community-based framework can support significant reductions in malaria prevalence by minimizing both indoor and outdoor malaria transmissions.

Keywords

Local knowledgeMalaria trendsCommunity-based strategiesFramework

Sediments on the bottom of Lake Challa, a 92-meter deep crater lake on the border of Kenya and Tanzania near Mt. Kilimanjaro, contain a uniquely long and continuous record of past climate and environmental change. The near-equatorial location and exceptional quality of this natural archive provide great opportunities to study tropical climate variability at both short (inter-annual to decadal) and long (glacial-interglacial) time scales; and the influence of this climate variability on the region's freshwater resources, the functioning of terrestrial ecosystems, and the history of the East African landscape in which modern humans (our species, Homo sapiens) evolved and have lived ever since. Supported in part by the International Continental Scientific Drilling Programme (ICDP), the DeepCHALLA project has now recovered the sediment record of Lake Challa down to 214.8 meter below the lake floor, with almost certain 100% cover of the uppermost 121.3 meter (ca.150,000 year BP to present) and estimated 85% cover over the lower part of the sequence, down to the lowermost distinct reflector in the available seismic stratigraphy. This reflector represents a 2 meter thick layer of volcanic sand and silt deposited ca.250,000 years ago, and overlies still older silty lacustrine clays deposited during early lake development. Down-hole logging produced continuous profiles of in-situ sediment composition that confer an absolute depth scale to both the recovered cores and their three-dimensional representation in seismic stratigraphy. As readily observed through the transparent core liners, Lake Challa sediments are finely laminated throughout most of the recovered sequence. Combined with the great time span, the exquisite temporal resolution of these sediments promises to greatly increase our understanding of tropical climate and ecosystem dynamics, and create a long-awaited equatorial counterpart to the high-latitude climate records extracted from the ice sheets of Greenland and Antarctica.

The possibility of a causal relationship between Earth history processes and hominin evolution in Africa has been the subject of intensive paleoanthropological research for the last 25 years. One fundamental question is: can any geohistorical processes, in particular, climatic ones, be characterized with sufficient precision to enable temporal correlation with events in hominin evolution and provide support for a possible causal mechanism for evolutionary changes? Previous attempts to link paleoclimate and hominin evolution have centered on evidence from the outcrops where the hominin fossils are found, as understanding whether and how hominin populations responded to habitat change must be examined at the local basinal scale. However, these outcrop records typically provide incomplete, low-resolution climate and environmental histories, and surface weathering often precludes the application of highly sensitive, state-of-the-art paleoenvironmental methods. continuous and well-preserved deep-sea drill core records have provided an alternative approach to reconstructing the context of hominin evolution, but have been collected at great distances from hominin sites and typically integrate information over vast spatial scales. The goal of the Hominin Sites and Paleolakes Drilling Project (HSPDP) is to analyze climate and other Earth system dynamics using detailed paleoenvironmental data acquired through scientific drilling of lacustrine depocenters at or near six key paleoanthropological sites in Kenya and Ethiopia. This review provides an overview of a unique collaboration of paleoanthropologists and earth scientists who have joined together to explicitly explore key hypotheses linking environmental history and mammalian (including hominin) evolution and potentially develop new testable hypotheses. With a focus on continuous, high-resolution proxies at timescales relevant to both biological and cultural evolution, the HSPDP aims to dramatically expand our understanding of the environmental history of eastern Africa during a significant portion of the Late Neogene and Quaternary, and to generate useful models of long-term environmental dynamics in the region.

Sediments on the bottom of Lake Challa, a 92-m deep crater lake on the border of Kenya and Tanzania near Mt. Kilimanjaro, contain a uniquely long and continuous record of past climate and environmental change in easternmost equatorial Africa. Supported in part by the International Continental Scientific Drilling Programme (ICDP), the DeepCHALLA project has now recovered this sediment record down to 214.8 m below the lake floor, with 100% recovery of the uppermost 121.3 m (the last 160 kyr BP) and ca.85% recovery of the older part of the sequence, down to the lowermost distinct reflector identified in seismic stratigraphy. This acoustic basement represents a ca.2-m thick layer of coarsely laminated, diatom-rich organic mud mixed with volcanic sand and silt deposited 250 kyr ago, overlying an estimated 20-30 m of unsampled lacustrine deposits representing the earliest phase of lake development. Down-hole logging produced profiles of in-situ sediment composition that confer an absolute depth- scale to both the recovered cores and the seismic stratigraphy. An estimated 74% of the recovered sequence is finely laminated (varved), and continuously so over the upper 72.3 m (the last 90 kyr). All other sections display at least cm-scale lamination, demonstrating persistence of a tranquil, profundal depositional environment throughout lake history. The sequence is interrupted only by 32 visible tephra layers 2 to 9 mm thick; and by several dozen fine-grained turbidites up to 108 cm thick, most of which are clearly bracketed between a non-erosive base and a diatom-laden cap. Tie points between sediment markers and the corresponding seismic reflectors support a preliminary age model inferring a near-constant rate of sediment accumulation over at least the last glacial cycle (140 kyr BP to present). This great time span combined with the exquisite temporal resolution of the Lake Challa sediments provides great opportunities to study past tropical climate dynamics at both short (inter-annual to decadal) and long (glacial-interglacial) time scales; and to assess the multi-faceted impact of this climate change on the region's freshwater resources, the functioning of terrestrial ecosystems, and the history of the African landscape in which modern humans (our species, Homo sapiens) originally evolved and have lived ever since.

Sweet potato is one of the most important staple food crops consumed in Kenya and throughout Africa but yields are greatly reduced by plant parasitic nematodes (PPN). The aim of this study was to determine the prevalence of PPN in Kenyan sweet potato fields and their relationship with soil and climatic variables. Soil samples were collected from sweet potato fields in Busia, Teso, Kisii, Embu and Makueni counties. Thirteen nematode genera were identified across the five counties with Meloidogyne, Pratylenchus and Rotylenchus being the most prevalent. There was a significant (P <0.05) relationship between PPN abundance and sodium, calcium and iron. Canonical correspondence analysis of climatic variables revealed that the relationship between rainfall and nematode genera was significant (P <0.05) while maximum and minimum temperatures were not significant. This description of PPN assemblages associated with sweet potato in Kenya and their relationship with environmental variables provides a starting point from which appropriate nematode management strategies can be implemented.

The root knot nematode, Meloidogyne is one of the most economically damaging plant parasitic nematode groups, and are widely distributed in Kenyan agro-ecosystems. The aim of this study was to determine the diversity of Meloidogyne species in Kenyan sweet potato fields and identify sweet potato varieties that exhibit resistance to M. incognita. Meloidogyne species were collected from Nyanza, Western, Eastern and Central Provinces of Kenya. Mitochondrial DNA was used to differentiate Meloidogyne species. The most common species in all sampled regions was M. incognita. Meloidogyne hapla was recorded for the first time in Kenyan sweet potato growing areas (Mosocho, Matayos, Teso South, Manyatta, and Nzaui sub-counties), while M. enterolobii was observed in Kiharu, Matayos and Mosocho sub-counties and a novel Meloidogyne sp. was identified in Kiharu sub-county. Seventy-two sweet potato varieties collected from both agricultural fields and research stations in Kenya were evaluated for resistance to M. incognita under greenhouse conditions in two separate trials. Known susceptible (Beauregard) and resistant (Tanzania) sweet potato varieties were included as controls. Responses of sweet potato varieties to M. incognita infection was assessed by the number of eggs present and level of galling on a scale of 1–5, where 0 = 0 galls and 5 ≥ 100 galls. The reproduction index (RI) was used to classify the varieties as resistant or susceptible. There was a significant difference (P < 0.001) in the number of eggs, GI and RI among the varieties tested. Forty nine sweet potato varieties were considered very resistant and may be used in breeding programs to incorporate resistance against M. incognita into commercial cultivars of sweet potato or to use them in crop rotation programmes for management of RKN. The results on Meloidogyne species diversity in Kenyan sweet potato fields will also be useful in nematode management programs

One of the major challenges in understanding the evolution of our own species is identifying the role climate change has played in the evolution of hominin species. To clarify the influence of climate, we need long and continuous high-resolution paleoclimate records, preferably obtained from hominin-bearing sediments, that are well-dated by tephro- and magnetostratigraphy and other methods. This is hindered, however, by the fact that fossil-bearing outcrop sediments are often discontinuous, and subject to weathering, which may lead to oxidation and remagnetization. To obtain fresh, unweathered sediments, the Hominin Sites and Paleolakes Drilling Project (HSPDP) collected a ∼216-meter core (WTK13) in 2013 from Early Pleistocene Paleolake Lorenyang deposits in the western Turkana Basin (Kenya). Here, we present the magnetostratigraphy of the WTK13 core, providing a first age model for upcoming HSPDP paleoclimate and paleoenvrionmental studies on the core sediments. Rock magnetic analyses reveal the presence of iron sulfides carrying the remanent magnetizations. To recover polarity orientation from the near-equatorial WTK13 core drilled at 5°N, we developed and successfully applied two independent drill-core reorientation methods taking advantage of (1) the sedimentary fabric as expressed in the Anisotropy of Magnetic Susceptibility (AMS) and (2) the occurrence of a viscous component oriented in the present day field. The reoriented directions reveal a normal to reversed polarity reversal identified as the top of the Olduvai Subchron. From this excellent record, we find no evidence for the ‘Vrica Subchron’ previously reported in the area. We suggest that outcrop-based interpretations supporting the presence of the Vrica Subchron have been affected by the oxidation of iron sulfides initially present in the sediments -as evident in the core record- and by subsequent remagnetization. We discuss the implications of the observed geomagnetic record for human evolution studies.

The gradient of air temperature with elevation (the temperature lapse rate) in the tropics is predicted to become less steep during the coming century as surface temperature rises, enhancing the threat of warming in high-mountain environments. However, the sensitivity of the lapse rate to climate change is uncertain because of poor constraints on high-elevation temperature during past climate states. We present a 25,000-year temperature reconstruction from Mount Kenya, East Africa, which demonstrates that cooling during the Last Glacial Maximum was amplified with elevation and hence that the lapse rate was significantly steeper than today. Comparison of our data with paleoclimate simulations indicates that state-of-the-art models underestimate this lapse-rate change. Consequently, future high-elevation tropical warming may be even greater than predicted.

Two stratigraphic records from Kaitio in West Turkana, Kenya, span 1.87 - 1.34 Ma, and document environmental character and variability through a critical interval for human evolution and cultural development. The WTK13 core collected by the Hominin Sites and Paleolakes Drilling Project (HSPDP) recovered 216 m of sediment at 95% recovery. A parallel outcrop record of 180 m was investigated in exposures along the Kaitio laga close to the drill site. Six tephrostratigraphic markers, the Chari, Lokapetamoi, 22Q-3, Etirr, Ebei and KBS Tuffs are present in the outcrop and/or core. These were characterized by single-shard geochemical analysis, and provide links to the well-established tephrochronology of the Turkana Basin. Magnetic polarity stratigraphy of the two records documents the top of the Olduvai Subchron (C2N) at 1.78 Ma. The lithostratigraphic record, bolstered by magnetic susceptibility and sedimentary facies characterization, demonstrates a first-order transition from a deeper lacustrine system to a dynamic lake margin setting, followed by delta progradation. Facies analysis reveals repeated fluctuations of lake level at Milankovitch and sub-Milankovitch scales. Core-outcrop correlation allows detailed comparisons between diagenetically-prone outcrop samples and more pristine samples from the deep core. The excellent preservation of the core sediments makes it possible to obtain critical climate records of organic biomarkers, pollen, phytoliths and other proxies. This detailed archive of environmental variability is closely linked to the rich paleontological and archaeological discoveries from nearby sites and around the Turkana Basin.

BACKGROUND:

Rift Valley fever (RVF) is a vector-borne zoonotic disease that has an impact on human health and animal productivity. Here, we explore the use of vector presence modelling to predict the distribution of RVF vector species under climate change scenario to demonstrate the potential for geographic spread of Rift Valley fever virus (RVFV).
OBJECTIVES:

To evaluate the effect of climate change on RVF vector distribution in Baringo County, Kenya, with an aim of developing a risk map for spatial prediction of RVF outbreaks.
METHODOLOGY:

The study used data on vector presence and ecological niche modelling (MaxEnt) algorithm to predict the effect of climatic change on habitat suitability and the spatial distribution of RVF vectors in Baringo County. Data on species occurrence were obtained from longitudinal sampling of adult mosquitoes and larvae in the study area. We used present (2000) and future (2050) Bioclim climate databases to model the vector distribution.
RESULTS:

Model results predicted potential suitable areas with high success rates for Culex quinquefasciatus, Culex univitattus, Mansonia africana, and Mansonia uniformis. Under the present climatic conditions, the lowlands were found to be highly suitable for all the species. Future climatic conditions indicate an increase in the spatial distribution of Cx. quinquefasciatus and M. africana. Model performance was statistically significant.
CONCLUSION:

Soil types, precipitation in the driest quarter, precipitation seasonality, and isothermality showed the highest predictive potential for the four species.

The population growth in the world carries on the one hand, an increased demand of fresh water and on the other hand, a decrease of quality and quantity of this resource. To avoid this deterioration it is essential doing a good management of surface water and groundwater, specially the second one, which has become the major source of water supply for domestic, industrial and agricultural sectors of many countries (UNEP 1999). This groundwater management starts with an accurate hydrogeological characterization of aquifer systems, mainly in that aquifer systems in which is changing the abstraction regime. In this context of population growth and new abstraction regimes on aquifer system is where the project "Gro for Good: Groundwater Risk for Growth and Development" is founded by UPGro. This interdisciplinary project has the main goal to design, test and transfer to the society an innovative Groundwater Risk Management Tool to improve and get by new governance transformations the balance between economic growth, groundwater sustainability (in terms of quality and quantity) and human development (http://upgro.org/consortium/gro-for-good/). The study area is located on the south eastern coast of Kenya, in Kwale County. The Kwale coastal groundwater system formed by a shallow and deep aquifer systems has long served urban water demands and an established tourism industry but now faces unprecedented ground and surface water resource demands especially from KISCOL's (5,500 hectares of irrigated sugarcane) and the country's largest mining operation (Base Titanium Ltd.). Despite both companies have drilled deep boreholes around the study area (416 km2) to extract groundwater from deep aquifer; no major pumping activity has started yet, allowing baseline evaluation. Scattered around the study are 440 handpumps providing drinking water to over 90,000 people. The relationship between the shallow and deep aquifers remains uncertain and so, the future influence on groundwater level and its quality either. So, in order to define the system and start to understand the different complex interactions, we present the initial results of the first complete water sampling field campaign (September 2015). Water isotope data and major ions were analyzed from 78 shallow and deep wells and surface water spread around study area. This field survey has been useful to understand the recharge, discharge areas and groundwater quality of deep aquifer system and which will have an important role for sustainable water management in the of Kwale area. Acknowledgements The research is primarily supported under the NERC/ESRC/DFID Unlocking the Potential of Groundwater for the Poor (UPGro) as a Catalyst Grant (NE/L001950/1) with work extending until 2019 as a Consortium Grant (NE/M008894/1), see http://www.upgro.org. Data for the paper will be publicly posted on the National Geoscience Data Centre and the UK Data Archive under the terms of the UPGro data management agreement.

The East African Rift System (EARS) started in Late Oligocene to Early Miocene time and gradually propagated southwards from the Afar Depression, beginning in the Middle Miocene. The hot, low-density mantle material of the Afar Plume heated the overlying lithosphere, causing thinning, regional doming, and the earliest basaltic volcanism in southern Ethiopia. In Ethiopia, the Afar Depression, the Main Ethiopian Rift, and the broadly rifted zone of southwestern Ethiopia represent the northern segment of the EARS.

In the Kenyan sector of the EARS, uplift and doming also gave rise to the Kenya Dome. The radial flow patterns of the initial phonolites provide evidence for doming. Another important observation is that the rift geometry was greatly influenced by pre-existing structures of the underlying Mozambique Mobile Belt. Rifting proceeded through alternating episodes of volcanism and tectonics. Crossing into Tanzania, the influence of the neighbouring Tanzania Craton becomes evident. Here, the rift is expressed only in the northern part, splaying out in diverging half-graben valleys that are outside the Kenya Dome.

Large boundary faults and opposing flexural margins, producing mobile asymmetrical full and half-graben basins that are individually linked along the rift axis, mark the Western Rift Valley. These basins are frequently occupied by elongate and narrow lakes (largely freshwater) separated by accommodation zones and containing significant hydrocarbon resources especially in the Albertine Graben. Small to large lakes existed in the EARS during the Plio–Pleistocene. Lakes in the Western Rift are large and deep, whereas those in the Kenya, Main Ethiopian, and Afar Rifts are generally small and shallow. Geological records indicate that the lakes sensitively responded to orbital forcing as well as to local, regional, and global climatic, environmental, and tectonic changes, resulting in fluctuating lake sizes and even desiccation.

Groundwater is used extensively in the Central Kenya Rift for domestic and agricultural demands. In these active rift settings groundwater can exhibit high fluoride levels. In order to address water security and reduce human exposure to high fluoride in drinking water, knowledge of the source and geochemical processes of enrichment are required. A study was therefore carried out within the Naivasha catchment (Kenya) to understand the genesis, enrichment and seasonal variations of fluoride in the groundwater. Rocks, rain, surface and groundwater sources were sampled for hydrogeochemical and isotopic investigations, the data was statistically and geospatially analyzed. Water sources have variable fluoride concentrations between 0.02–75 mg/L. 73% exceed the health limit (1.5 mg/L) in both dry and wet seasons. F− concentrations in rivers are lower (0.2–9.2 mg/L) than groundwater (0.09 to 43.6 mg/L) while saline lake waters have the highest concentrations (0.27–75 mg/L). The higher values are confined to elevations below 2000 masl. Oxygen (δ18O) and hydrogen (δD) isotopic values range from − 6.2 to + 5.8‰ and − 31.3 to + 33.3‰, respectively, they are also highly variable in the rift floor where they attain maximum values. Fluoride base levels in the precursor vitreous volcanic rocks are higher (between 3750–6000 ppm) in minerals such as cordierite and muscovite while secondary minerals like illite and kaolinite have lower remnant fluoride (< 1000 ppm). Thus, geochemical F− enrichment in regional groundwater is mainly due to a) rock alteration, i.e. through long residence times and natural discharge and/or enhanced leakages of deep seated geothermal water reservoirs, b) secondary concentration fortification of natural reservoirs through evaporation, through reduced recharge and/or enhanced abstraction and c) through additional enrichment of fluoride after volcanic emissions. The findings are useful to help improve water management in Naivasha as well as similar active rift setting environments.

The influence of climate and environmental history on human evolution is an existential question that continues to
be hotly debated, in part because of the paucity of high resolution records collected in close proximity to the key
fossil and archaeological evidence. To address this issue and transform the scientific debate, the HSPDP was devel-
oped to collect lacustrine sediment drill cores from basins in Kenya and Ethiopia that collectively encompass crit-
ical time intervals and locations for Plio-Quaternary human evolution in East Africa. After a 17 month campaign,
drilling was completed in November, 2014, with over 1750m of core collected from 11 boreholes from five areas
(1930m total drilling length, avg. 91% recovery). The sites, from oldest to youngest, include 1) N. Awash, Ethiopia
(

3.5-2.9Ma core interval); 2) Baringo-Tugen Hills, Kenya (

3.3-2.5Ma); 3) West Turkana, Kenya (

1.9-1.4Ma);
L. Magadi, Kenya (0.8-0Ma) and the Chew Bahir Basin, Ethiopia (

0.5-0Ma). Initial core description (ICD) and
sampling for geochronology, geochemistry and paleoecology studies had been completed by mid2014, with the
two remaining sites (Magadi and Chew Bahir) scheduled for ICD work in early 2015. Whereas the primary scien-
tific targets were the lacustrine deposits from the hominin-bearing basin depocenters, many intervals of paleosols
(representative of low lake stands and probable arid periods) were also encountered in drill cores. Preliminary anal-
yses of drill core sedimentology and geochemistry show both long-term lake level changes and cyclic variability in
lake levels, both of which may be indicative of climatic forcing events of interest to paleoanthropologists. Authors
of this abstract also include the entire HSPDP field team

The role that climate and environmental history may have played in influencing human
evolution has been the focus of considerable interest and controversy among
paleoanthropologists for decades. Prior attempts to understand the environmental history
side of this equation have centered around the study of outcrop sediments and fossils
adjacent to where fossil hominins (ancestors or close relatives of modern humans) are
found, or from the study of deep sea drill cores. However, outcrop sediments are often highly
weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea
core records come from long distances away from the actual fossil and stone tool remains.
The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address
these issues.

In the coming century the world's high tropical mountains are predicted to experience a magnitude of climate change second only to the Arctic due to amplification of warming with elevation in the tropics. Proxy data suggest that substantial changes in tropical temperature and hydroclimate also occurred during the last deglaciation, the most recent time period when rising atmospheric CO2 concentrations caused large changes in global climate. Determining whether the rate of temperature change with elevation (the lapse rate) was different from today during the Last Glacial Maximum (LGM) is therefore critical to understanding the future of tropical mountain environments and resources. Here we present a new 25,000-year temperature reconstruction based upon organic geochemical analyses of sediment cores from Lake Rutundu (3,078 m asl), Mount Kenya, East Africa. Through comparison with regional reconstructions of lower elevation temperature, we show that LGM cooling was amplified with elevation and hence that the lapse rate was significantly steeper than today. Comparison of our lapse rate reconstructions with equilibrium line altitude reconstructions from glacial moraines indicates that temperature, rather than precipitation, was the dominant control on tropical alpine glacier fluctuations at this time scale. Nevertheless, our results have important implications for the tropical hydrological cycle, as changes in the lapse rate are intimately linked with changes in atmospheric water vapour concentrations. Indeed, we attribute the steeper lapse rate to drying of the tropical ice-age atmosphere, a hypothesis supported by palaeoclimate models. However, comparison of our data to these simulations indicates that state-of-the-art models significantly underestimate tropical temperature changes at high elevation and therefore the lapse-rate change. Consequently, future high-elevation tropical warming may be even greater than currently predicted.

The Rift Valley fever (RVF) is a vector-borne zoonotic disease that has an impact on human health and animal productivity. It is caused by the Rift Valley Fever Virus (RVFV) which is primarily transmitted by flood water Aedes mosquitoes. Culex spp and Mansonia spp are secondary vectors which pick up the RVFV from domestic animals and amplify the infection to other domestic animals and humans. This study used ecological niche modelling algorithms to predict the effect of climatic variables on habitat suitability and the spatial distribution of RVF vectors in Baringo County. We ran the Boosted Regression trees and Random Forest algorithms to model the spatial distribution of Culex spp. using species occurrence data and AFRICLIM climate data. The species occurrence data was obtained from longitudinal sampling of mosquito larvae in four strata within the study area between June and December 2014. The AFRICLIM climate data consisting of 21 variables was downloaded from https://webfiles.york.ac.uk/KITE/AfriClim. Preliminary results indicate that rainfall, moisture and temperature ranges are the key factors that affect the spatial distribution of Culex spp in Baringo County. Culex spp. is likely to be found in the riverine zone along Kerio River and in the lowlands around Lakes Baringo, 94 and Bogoria.

The influence of climate and environmental history on human evolution is an existential question that continues to be hotly debated, in part because of the paucity of high resolution records collected in close proximity to the key fossil and archaeological evidence. To address this issue and transform the scientific debate, the HSPDP was developed to collect lacustrine sediment drill cores from basins in Kenya and Ethiopia that collectively encompass critical time intervals and locations for Plio-Quaternary human evolution in East Africa. After a 17 month campaign, drilling was completed in November, 2014, with over 1750m of core collected from 11 boreholes from five areas (1930m total drilling length, avg. 91% recovery). The sites, from oldest to youngest, include 1) N. Awash, Ethiopia (~3.5-2.9Ma core interval); 2) Baringo-Tugen Hills, Kenya (~3.3-2.5Ma); 3) West Turkana, Kenya (~1.9-1.4Ma); L. Magadi, Kenya (0.8-0Ma) and the Chew Bahir Basin, Ethiopia (~0.5-0Ma). Initial core description (ICD) and sampling for geochronology, geochemistry and paleoecology studies had been completed by mid2014, with the two remaining sites (Magadi and Chew Bahir) scheduled for ICD work in early 2015. Whereas the primary scientific targets were the lacustrine deposits from the hominin-bearing basin depocenters, many intervals of paleosols (representative of low lake stands and probable arid periods) were also encountered in drill cores. Preliminary analyses of drill core sedimentology and geochemistry show both long-term lake level changes and cyclic variability in lake levels, both of which may be indicative of climatic forcing events of interest to paleoanthropologists. Authors of this abstract also include the entire HSPDP field team.

Between the summers of 2013 and 2014, the HSPDP successfully completed 4 of its 5 drilling campaigns. To date, >1,200m of core has been collected with the final site at Chew Bahir, Ethiopia scheduled for the end of 2014. The initial core description and sampling have been completed on all but the Magadi cores. Despite the challenges associated with a large-scale multinational project, we have accomplished our goal of collecting lacustrine dominated cores proximate to key paleoanthropological sites. Challenges included the availability/import of suitable drill rigs and equipment in country, long supply lines in remote areas, challenging lithologies for coring and recovery, and interpretation of geophysical data. At our oldest site, 600m of Pliocene-age core was collected from 3 boreholes at 2 sites in the northern Awash, Ethiopia. This resulted in a composite depth of ~285m with significant overlap between cores and >96% core recovery. Several unexpectedly thick basalts not originally identified in seismic surveys were interbedded with lake sediments. Drilling ceased prior to reaching our original target of 500m when rehydrated clays made advancing impractical and work in progress will determine how much of the 2.9-3.8Ma target interval was recovered. A single 228m borehole with ~95% core recovery was drilled at the Plio-Pleistocene Tugen Hills, Kenya location. Just shy of our 250m target depth, preliminary comparisons with outcrop records suggest that this core may cover a time interval of ~2.5-3.45Ma, longer than our original target of 2.5-3.1Ma. A single 216m borehole with ~93% core recovery was drilled at the early Pleistocene West Turkana, Kenya location. Drilling ceased prior to reaching our original target depth of 350m due to complications likely associated with penetrating a hydrothermal fracture system. Nonetheless, tephrostratigraphic data indicates that the core covers our original target interval of ~1.45-2.0Ma. Recently, 202m of modern to Middle Pleistocene core was collected from 4 boreholes at 2 sites at Lake Magadi, Kenya. Challenging lithologies to core/collect (e.g., trona, chert) resulted in core recovery of 55-60%. Contact with the basement trachyte (~800 ka) at each site occurred at 137m and 197m, respectively, shallower than original estimates from low-resolution geophysical surveys.

Lake sediment cores spanning the last interglacial-glacial-present interglacial cycle have been recovered from Sacred Lake and Lake Nkunga on the northeastern flank of Mount Kenya, Kenya. Within these cores are diamicts which occur at the last interglacial-glacial transition (ca.110,000 yr BP) and between 58,000 and 48,000 yr BP. The occurrence of the diamicts (formed by active freeze-thaw processes in the lake catchments) is associated with periglacial and concurrent relatively humid conditions at the altitudes of the lakes. In addition, their temporal occurrence is correlated with abrupt low temperature extremes and/or rapid transition rates to lower temperature regimes at high latitude regions. Close modern corollaries of such sediments have been documented at higher altitude on Mount Kenya, but there is no known documentation of such sediments in the late Quaternary records of the tropical high mountains.

This chapter focuses on the existing information on the hydrodynamics and sediment transport processes along the Kenyan coastline. Although the low-lying coastline is under threat from coastal erosion that has led to its destabilization, the factors are linked to local and global processes. Changes in land used for agriculture have led to increase sediment fluxes which have resulted in increase in turbidity and siltation. Other activities such as coral and mangrove harvesting, seawall construction, urbanization and lack of regulations on the construction of structures along of the coastline can be linked to the coastal erosion processes. Among the global factors, the Kenyan coastline has been affected by the extreme events such as the El Niño event of 1997/1998, which led to devastating effects such as an increase in sediment fluxes and turbidity, coral bleaching and mortality and substantial sea level rise. A 1.3 °C sea surface temperature rise on the western side of the Indian Ocean has been recorded since 1880; this makes the coastline vulnerable to the impacts of the predicted 6 °C temperature rise in East Africa due to climate change. It is estimated that the biggest coastal city of Mombasa will be 17% submerged by 2100 and the Tana delta will experience a 5% loss as a consequence of climate change due to the frequent storms that are anticipated. Although the 2004 global tsunami events did not have devastating effects on the Kenyan coast, the event hit the coastline at low tide and this led to the limited damage. In the management of the shoreline, currently an Integrated Coastal Zone Management strategy does not exist although efforts are underway to develop a shoreline management strategy that incorporates the principles of the integration in the management of the coastline. These efforts are encouraged by the success of the marine protected areas of Malindi and Watamu and the current co-management strategy adapted by the Ministry of Fisheries through the Beach Management Units that engages the resource users as equal partners in the management of the coastal resources.
Keywords

Urbanization;
Sediment flux;
El Niño;
Sea surface temperature;
Tsunami;
Mombasa;
Tana delta;
Marine protected areas;
Beach Management Units

Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

Kenya is a thriving country in East Africa: its economy is largely based on the natural environment that frames the tourism sector, mainly through safaris and holidays on the coast. The natural environment also underpins the second largest industry: agriculture. Kenya’s social, technological, and industrial developments are a reference for many neighboring countries. Kenya plays a leading role in Africa and attracts huge amounts of investments. Furthermore, the humanitarian community has made Nairobi its base for international headquarters and regional offices. This makes Kenya a possible model for development and investment in its widest sense. This book aims at updating the holistic view on Kenya’s natural environment and resources. It provides a sound scientific introduction to this country’s physical and socioeconomic setting and its evolution through time and will appeal to a broad audience of students – in Kenya and abroad – as well as those working in the development and humanitarian sectors and to international donors looking for a scientific compendium on Kenya’s environment. Its structure and references allow the reader to deepen his or her knowledge of every theme touched on in the book.

Within the East African rift, groundwater recharge results from the complex interplay of geology, land cover, geomorphology, climate and on going volcano-tectonic processes across a broad range of spatial and temporal scales. The interrelationships between these factors create complex patterns of water availability, reliability and quality. The hydrochemical evolution of the waters is further complex due to the different climatic regimes and geothermal processes going on in this area. High fluoridic waters within the rift have been reported by few studies, while dental fluorosis is high among the inhabitants of the rift. The natural sources of fluoride in waters can be from weathering of fluorine bearing minerals in rocks, volcanic or fumarolic activities. Fluoride concentration in water depends on a number of factors including pH, temperature, time of water-rock formation contact and geochemical processes. Knowledge of the sources and dispersion of fluoride in both surface and groundwaters within the central Kenya rift and seasonal variations between wet and dry seasons is still poor. The Central Kenya rift is marked by active tectonics, volcanic activity and fumarolic activity, the rocks are majorly volcanics: rhyolites, tuffs, basalts, phonolites, ashes and agglomerates some are highly fractured. Major NW-SE faults bound the rift escarpment while the rift floor is marked by N-S striking faults We combine petrographic, hydrochemistry and structural information to determine the sources and enrichment pathways of high fluoridic waters within the Naivasha catchment. A total of 120 water samples for both the dry season (January-February2012) and after wet season (June-July 2013) from springs, rivers, lakes, hand dug wells, fumaroles and boreholes within the Naivasha catchment are collected and analysed for fluoride, physicochemical parameters and stable isotopes (δ2 H, δ18 O) in order to determine the origin and evolution of the waters. Additionally, 30 soil and rock samples were also collected and analysed for fluoride, and rock samples were subjected to petrographic investigations and X-ray diffraction. The fluoride levels in surface and groundwater for the dry season range from 0.019 - 50.14 mg/L, on average above the WHO permissible limit. The high fluoride occurs both in the lake and groundwater. Preliminary petrographic studies show considerable fluoride in micas. The study is on-going and plans to present the relative abundances of fluoride in the lithology as the sources and the fluoride enrichment pathways of the groundwater within the Central Kenya rift.

The mineral, oil and gas sectors have not played an important role in the economy of Kenya in the past, but the recent discovery of mineral sands and rare earth elements at the coast and oil in the Lokichar Basin in the northern part of the country are proving to be game changers in the mining, oil and gas sectors. The most important minerals mined in the past have been mainly industrial minerals with soda ash and fluorspar being the most important products. Significant tonnage of gold was mined in western parts of Kenya, but currently only minor exploration and production from the old mine sites is taking place. However, with the increased interest and the government resolve to improve mineral exploration, new mineral finds are possible. Exploration for oil and gas has been taking place in Kenya since the 1950s, but it is only recently that significant oil finds have been reported. The findings have inspired several companies to explore for oil and gas within all the major sedimentary basins in Kenya, namely, the Lokichar Basin, Turkana Basin, the Kerio and Baringo Basin, the Anza Basin, and the Lamu Basin.

We studied the most recent dry-wet-dry cycle in the presently arid Suguta Valley in the Northern Kenya Rift where a 300-m-deep lake has formed during the so-called African Humid Period (AHP, 14.8-5.5 ka BP). Hydromodeling suggests that a relatively moderate 25% increase in precipitation was responsible for this dramatic lake level rise, which demonstrates the character of the Suguta Valley as an amplifier lake system. To detect the response of this lake system to climate fluctuations and their possible driving mechanisms with a focus on abrupt vs. gradual changes, we reconstructed a palaeo-lake level record for the time between 14 and 5 ka BP from up to 40 m thick lake-sediment sequences at three locations in the ~2,500 km2 palaeo-lake Suguta area. The sediments have been investigated for sediment characteristics such as grain size distributions, detrital and authigenic mineral phases, geochemical properties and microfossil assemblages. The stratigraphy for the sequences is based on 38 AMS 14C ages of biogenic carbonate and charcoal samples. Parallel dating of charcoal and snail-shell samples show age differences between 1,570-2,240 years suggesting a remarkably high, but well-defined reservoir age for palaeo-Lake Suguta most likely due to aged groundwater or 14C depleted CO2 degassing from active volcanoes. The observed reservoir effect highlights the potential problems while correlating East African lake level records with chronologies based on 14C datings of aquatic materials. The new chronology of water level fluctuations in the amplifier-lake Suguta indicates a general dry-wet-dry cycle synchronous with other lake chronologies during the AHP and multiple short-term fluctuations with abrupt lake level drops between 100 to 300 m within 100 to 200 years at 12.8-11.6 (during Younger Dryas time), 11.1-10.9; 10.4-10.2; 9.5-9.1; 9.0-8.8; 8.5-8.1 (during the 8.2 ka event) cal ka BP that seem to be linked with changes in the coupling between atmosphere and ocean systems. In contrast, the termination of the overall lake episode during the AHP shows a relatively gradual (linear) response to the reduction of solar heating due to insolation changes. The results of the analysis provides new insights into the sensitivity of Rift Valley lakes to climate change on different time scales. Abrupt climate shifts most likely caused dramatic environmental pressure on the biosphere, including humans that were already able to adopt relatively quickly to environmnetal change by new technologies during this time.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a nonionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (M, approximately 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr approximately 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, the reproductive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively.

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In the tropical regions, lake and swamp sediment core chronologies have traditionally been established solely by radiocarbon dating. In several instances, however, the radiocarbon sampling resolution has been coarse, entailing extrapolations over time periods where there may have been considerable change in sedimentation rates related, for example, to significant, albeit abrupt, palaeoclimatic and palaeoenvironmental change. Moreover, some cores may age-wise exceed the radiocarbon dating limit of ca.40,000 yr, thus entailing tenuous extrapolations of radiocarbon dates obtained in the younger sections of the core in order to obtain a whole core chronology. In this paper, the chronology of lake sediment cores retrieved from Sacred Lake and Lake Nkunga on the north-eastern flank of Mount Kenya is established using a combination of highresolution radiocarbon dating and experimental U/Th dating to circumvent the drawbacks mentioned above. The derived chronosequences, which show that these sediment records span almost the whole of the late Quaternary period, demonstrate the efficacy and synergism of these dating techniques.

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