Kenya Rift Research Articles

Using GIS and Remote Sensing in Assessment of Water Scarcity in Nakuru County, Kenya

Water is at the core of sustainable development and is critical for socio-economic development, healthy ecosystems and for human survival. This research study has been carried out in Nakuru County, a tropical region in the Rift Valley of Kenya, bounded between latitude 0.28°N and 1.16°S, and longitude 36.27°E and 36.55°E. The objective of the study has been to use GIS and remote sensing in assessment of water scarcity using Land use Land cover area changes, standard precipitation index and crop yields. Landsat satellite images for the year 1985, 1995, 2005 and 2015 were used. Classification was done using maximum likelihood algorithm while classification accuracy assessment entailed the use of confusion matrix method and ground truth data. Post classification change detection results gave percentage cropland areas as 21% in 1985, 29% in 1995, 53% in 2005 and also 53% in 2015. Eleven (11) ground rainfall stations and TRMM satellite rainfall data from 1985 to 2015 has been used to show meteorological drought. Validation of rainfall data done using correlation coefficient (R2) and root mean square (RMS) methods showed that ground rainfall data and TRMM data correlate. Modelling of 3 months SPI for each of the three seasons (MAM, JJA and OND) has been done using interpolation distance weighted method (IDW). 3 months SPI time scales curves gave October 1987 May 1993, and July 2004 as water scarce and dry seasons and were categorized as either Normal, moderately dry, severely dry and extremely dry. Crop yield trends curves showed crop yield decrease in this identified water scarce and dry years. Conclusion reached is that crop yields is not dependent on size of land ploughed only but mostly on rainfall quantities. Therefore, the findings of this research can be used as drought monitoring tools.

A Preliminary Assessment of the Hydrocarbon Potential of Kerio Valley Basin: Gravity and Magnetic Interpretation

The aim of the study was to assess the hydrocarbon prospectivity of the Kerio Basin in the Kenya Rift. Regional gravity and magnetic data sourced from the International Gravity Bureau (BGI) and Earth Magnetic Anomaly grid (EMAG2) respectively, were processed and analysed for major structures and geological anomalies based on variations in density magnetism and or chemistry of the rocks.Gravity Isostacy data shows low gravity anomalies of up to -100mGals that depict a deeper basement prominent to the southern part of the study area. Gravity profiles show that sediment thickness gradually increases to the south where we expect hydrocarbon accumulation. The magnetic anomaly map reveals low susceptibility rocks of between - 20nT to -200nT to the south of the basin. Magnetic tilt depth indicates sediment thickness of 2-3.5Km above the basement. The results agree with the observed gravity values of -100mGals to -200mGals in the same area. Hence the southern part of the study area shows the highest potential for hydrocarbon accumulation. Integration of these data with seismic and other geophysical methods in the southern area of the Kerio Basin can help gauge the hydrocarbon potential and reduce the uncertainty in the preliminary results.

Short-lived increase in erosion during the African Humid Period: Evidence from the northern Kenya Rift

The African Humid Period (AHP) between ∼15 and 5.5 cal. kyr BP caused major environmental change in East Africa, including filling of the Suguta Valley in the northern Kenya Rift with an extensive (∼2150 km2), deep (∼300 m) lake. Interfingering fluvio-lacustrine deposits of the Baragoi paleo-delta provide insights into the lake-level history and how erosion rates changed during this time, as revealed by delta-volume estimates and the concentration of cosmogenic 10Be in fluvial sand. Erosion rates derived from delta-volume estimates range from 0.019 to 0.03 mm yr−1. 10Be-derived paleo-erosion rates at ∼11.8 cal. kyr BP ranged from 0.035 to 0.086 mm yr−1, and were 2.7 to 6.6 times faster than at present. In contrast, at ∼8.7 cal. kyr BP, erosion rates were only 1.8 times faster than at present. Because 10Be-derived erosion rates integrate over several millennia, we modeled the erosion-rate history that best explains the 10Be data using established non-linear equations that describe in situ cosmogenic isotope production and decay. Two models with different temporal constraints (15–6.7 and 12–6.7 kyr) suggest erosion rates that were ∼25 to ∼300 times higher than the initial erosion rate (pre-delta formation). That pulse of high erosion rates was short (∼4 kyr or less) and must have been followed by a rapid decrease in rates while climate remained humid to reach the modern 10Be-based erosion rate of ∼0.013 mm yr−1. Our simulations also flag the two highest 10Be-derived erosion rates at ∼11.8 kyr BP related to non-uniform catchment erosion. These changes in erosion rates and processes during the AHP may reflect a strong increase in precipitation, runoff, and erosivity at the arid-to-humid transition either at ∼15 or ∼12 cal. kyr BP, before the landscape stabilized again, possibly due to increased soil production and denser vegetation.

Erratum to: Characterising and comparing drug-dispensing practices at animal health outlets in the Rift Valley, Kenya: an exploratory analysis (part II).

A mixed-method study was conducted in the Rift Valley of Kenya to characterise drug-dispensing practices amongst staff at animal health outlets and to explore perceptions of veterinary medicines amongst pastoralists and farmers. Forty structured questionnaires were administered to staff at animal health outlets, including franchise outlets of ‘Sidai Africa Ltd.’, and two focus group discussions were facilitated to explore the perceptions of local animal health services by a Maasai pastoralist group and a dairy farmer cooperative. Differences were detected in the characteristics of Sidai outlets, agrovets, pharmacies and dukas. A greater proportion of Sidai outlet staff selected drugs based on principles of responsible drug use than staff at other types of outlet, and technical qualifications and training were associated with responsible drug use. Across all outlet types, staff knowledge and training gaps were identified, including in the correct administration of medicines. The majority of drug sales are accompanied by verbal advice to farmers. Members of the Maasai pastoralist group were concerned about accidental self-medication, withdrawal periods, drug residues and the misuse of drugs due to a lack of quality information and advice. The dairy farmer group raised similar concerns, reporting under-dosing as a common mistake amongst farmers. This study concludes that current knowledge, attitudes and practices of many service providers and livestock owners in the sale, purchase and use of veterinary medicines present risks of drug misuse and therefore the emergence of antimicrobial resistance. There is a clear demand from livestock keepers for accessible, affordable and quality animal health services and products in Kenya, and animal health practitioners have the potential to provide increased support to livestock-based livelihoods and act as stewards of our existing portfolio of animal and human medicines.

Mapping evaporite minerals and associated sediments in Lake Magadi, Kenya, using Hyperspectral Hyperion data

Hyperion hyperspectral (VNIR-SWIR) satellite image data was used to map the spatial distribution of mineral precipitates at Lake Magadi area, in the southernmost part of the eastern Kenya rift, Kenya. Mapping was coupled with laboratory analysis, including visible near infrared diffuse reflectance spectroscopy (VNIR) measurements and X-ray diffraction for selected rock and soil samples. The VNIR spectral responses of 92 rock and soil samples including trona, chert, diatomite, basalt/trachyte, erionite, Green bed and High Magadi bed were studied and identified. The spectral signatures of Chert samples show the broad Si-OH absorption feature at 2.2 μm while, Green bed, High Magadi bed and diatomite exhibit carbonate absorption feature at 2.35 μm with broad Si-OH absorption feature at 2.2 μm. Trona exhibits six common absorption features at 1.50, 1.74, 1.94, 2.03, 2.22 and 2.39 μm. These characteristics spectral absorption features together with the general shape of the spectral curve are used to identify the surface minerals of the area. In the mapping of different stages of evaporites and other surface minerals using Hyperion data, various image processing techniques including, the Minimum Noise Fraction (MNF), Pixel Purity Index (PPI) and Mixture Tuned Matched Filtering (MTMF) were applied. These spectral mapping methods coupled with geochemical knowledge of the area substantially improved the existing geological knowledge and enhanced the capability to derive substantial information related to the distribution and formation of precipitates and evaporites in the area.

Elemental fingerprinting of Kenya Rift Valley ochre deposits for provenance studies of rock art and archaeological pigments

Abstract The Kenya Rift Valley contains many ochre sources that are currently used by indigenous peoples for adornment, rituals, and art. Ochre pigments occur in rock art and archaeological sites spanning over 250,000 years. Chemical analysis for provenience of geological sources is the first step in the process of reconstructing provenance of archaeological artifacts for cultural heritage, archaeological, and paleoanthropological research. Development of an ochre source chemical composition database can facilitate reconstruction of social interaction networks and cultural heritage conservation efforts in this region. Techniques such as Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) and Instrumental Neutron Activation Analysis (INAA) are often used for compositional analysis and sourcing of ferruginous mineral pigments. Sourcing has proven challenging due to the diverse range of rocks and minerals that are classified as red and yellow ochres, and the diverse processes that induce variation in composition, including modes of formation, sedimentary transport of parent materials, and diagenesis. Attribution of samples to specific sources is possible only when variation within sources is less than differences between sources (the Provenience Postulate). Here we present the results of a study using LA-ICPMS to determine inter- and intra-source geochemical variations for ten ochre sources associated with three large volcanic centers in the central Rift Valley of Kenya. Our results show that differences in chemical composition among sources are greater than variation within sources, both at the scale of large volcanic centers and of individual ochre outcrops within these centers. Clear differentiation of source chemical fingerprints at local and regional scales satisfies the Provenience Postulate, and suggests that provenance studies of ochre artifacts, residues, and rock art in Kenya will be feasible.

Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact

In the area south-east of Mount Kenya, four previously unrecorded peralkaline rhyolitic (pantelleritic) ash flow tuffs have been located. These predominantly greyish welded and non-welded tuffs form up to 12m thick units, which are sometimes characterized by a basal vitrophyre. The four flow units yielded 40Ar/39Ar ages ranging from 6.36 to 8.13Ma, indicating a period of ~1.8Ma of pantelleritic volcanic activity during the Late Miocene in central Kenya. Tentative compositional and age correlations with other known tuff deposits suggest that the pantelleritic tuffs originally covered 40,000km2 in central Kenya, extending much further than earlier recorded Pliocene tuffs. This newly identified magmatic phase occurred between the phonolitic flood eruptions (16–8Ma) and the Pliocene tuff eruptions (6–4Ma). The occurrence of multiple ash flow tuff deposits up to 150km away from the inferred eruptive center(s) in the central sector of the Kenya Rift, indicates multi-cyclic peralkaline supereruptions during the Late Miocene. By analogy with more recent pantelleritic eruptions, the tuffs are thought to have been sulfur-rich; during eruption, they formed stratospheric aerosols, with significant environmental impact. The timing of the eruptions coincides with the shift towards more savannah-dominated environments in East Africa.

Edaphic and Topographic Constraints on Exploitation of the Central Kenya Rift by Large Mammals and Early Hominins

Our aim in this paper is to create a palaeoenvironmental and spatio-temporal framework for interpreting human land use and exploitation of large mammals in the Central Kenya Rift over the past 2 million years, with particular reference to the Nakuru-Elmenteita-Naivasha basin and its adjacent rift flanks on the Kinangop Plateau and Mau escarpment. We pay particular attention to the tectonic and volcanic history of the region, and to the system of lakes that have undergone periodic expansion and contraction during the Pleistocene in response to climatic and tectonic controls. We use this information to reconstruct topographic features as they would have existed at different periods of the past and their likely influence on patterns of large-mammal movements. In addition we present a systematic mapping of variations in the mineral nutrients of soils – soil edaphics – based on 150 analyses of trace elements in modern soil and vegetation samples. Soil edaphics play an important role in animal and human health today, with serious deficiencies in some areas, and would have exerted an important constraint on animal distributions and movements in the past. We show how soil-edaphic properties vary across the region and demonstrate a close relationship between them and the underlying geology and sediments, which allows us to project patterns back into the past and extrapolate them over larger areas. Using this combination of variables, we construct maps that help to place archaeological sites into their wider regional setting. We focus in particular on the Acheulean site of Kariandusi and show that it occupied a unique window of opportunity in place and time for trapping mammals constrained to move through a narrowly defined topographic bottleneck between edaphically-rich areas. We infer that the site was used for a simple form of ambush hunting and briefly explore the implications for differential site use, formation, preservation and visibility.

English

Participatory epidemiological methods were used to establish local perceptions and livestock owner’s knowledge, attitudes and practices (KAPs) of risk factors that impacts of climate variability and the seasonal variations in incidences of livestock diseases, disease vectors, intermediate hosts and rainfall in pastoral Rift valley of Kenya. The interaction of the molecular biology of the pathogen itself; vectors (if any); farming practice, land use; zoological and environmental factors; and the establishment of new microenvironments and microclimates were important in forecasting how contagious caprine pleuronemonia, enterotoxaemia and sheep and goat pox occurred. Thus, the future for traditional pastoralists is depressing if they depend on an environment that may no longer support them. A risk assessment framework is proposedwas used, to examine factors based on modules that accommodate these factors. Risk assessments focused on examining the combinations of factors directly affected by climate change or indirectly by human activity, such as land use (e.g. deforestation), transport and movement of animals, intensity of livestock farming and habitat change and their relationship with should be done. This used to screen for the emergence of unexpected disease events. The present study recommended implementing disease management practices and policy measures to mitigate the impact of climate variability on the spread of livestock diseases. Key words: Climate change, participatory epidemiology, incidences of small ruminant diseases, pastoral areas.

Bacteria and Archaea diversity within the hot springs of Lake Magadi and Little Magadi in Kenya

BackgroundLake Magadi and little Magadi are hypersaline, alkaline lakes situated in the southern part of Kenyan Rift Valley. Solutes are supplied mainly by a series of alkaline hot springs with temperatures as high as 86 °C. Previous culture-dependent and culture-independent studies have revealed diverse groups of microorganisms thriving under these conditions. Previous culture independent studies were based on the analysis of 16S rDNA but were done on less saline lakes. For the first time, this study combined illumina sequencing and analysis of amplicons of both total community rDNA and 16S rRNA cDNA to determine the diversity and community structure of bacteria and archaea within 3 hot springs of L. Magadi and little Magadi.MethodsWater, wet sediments and microbial mats were collected from springs in the main lake at a temperature of 45.1 °C and from Little Magadi “Nasikie eng’ida” (temperature of 81 °C and 83.6 °C). Total community DNA and RNA were extracted from samples using phenol-chloroform and Trizol RNA extraction protocols respectively. The 16S rRNA gene variable region (V4 – V7) of the extracted DNA and RNA were amplified and library construction performed following Illumina sequencing protocol. Sequences were analyzed done using QIIME while calculation of Bray-Curtis dissimilarities between datasets, hierarchical clustering, Non Metric Dimensional Scaling (NMDS) redundancy analysis (RDA) and diversity indices were carried out using the R programming language and the Vegan package.ResultsThree thousand four hundred twenty-six and one thousand nine hundred thirteen OTUs were recovered from 16S rDNA and 16S rRNA cDNA respectively. Uncultured diversity accounted for 89.35 % 16S rDNA and 87.61 % 16S rRNA cDNA reads. The most abundant phyla in both the 16S rDNA and 16S rRNA cDNA datasets included: Proteobacteria (8.33–50 %), Firmicutes 3.52–28.92 %, Bacteroidetes (3.45–26.44 %), Actinobacteria (0.98–28.57 %) and Euryarchaeota (3.55–34.48 %) in all samples. NMDS analyses of taxonomic composition clustered the taxa into three groups according to sample types (i.e. wet sediments, mats and water samples) with evident overlap of clusters between wet sediments and microbial mats from the three sample types in both DNA and cDNA datasets. The hot spring (45.1 °C) contained less diverse populations compared to those in Little Magadi (81–83 °C).ConclusionThere were significant differences in microbial community structure at 95 % level of confidence for both total diversity (P value, 0.009) based on 16S rDNA analysis and active microbial diversity (P value, 0.01) based on 16S rRNA cDNA analysis, within the three hot springs. Differences in microbial composition and structure were observed as a function of sample type and temperature, with wet sediments harboring the highest diversity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0748-x) contains supplementary material, which is available to authorized users.

Diffuse degassing at Longonot volcano, Kenya: Implications for CO2 flux in continental rifts

Magma movement, fault structures and hydrothermal systems influence volatile emissions at rift volcanoes. Longonot is a Quaternary caldera volcano located in the southern Kenyan Rift, where regional extension controls recent shallow magma ascent. Here we report the results of a soil carbon dioxide (CO2) survey in the vicinity of Longonot volcano, as well as fumarolic gas compositions and carbon isotope data. The total non-biogenic CO2 degassing is estimated at <300kgd−1, and is largely controlled by crater faults and fractures close to the summit. Thus, recent volcanic structures, rather than regional tectonics, control fluid pathways and degassing. Fumarolic gases are characterised by a narrow range in carbon isotope ratios (δ13C), from −4.7‰ to −6.4‰ (vs. PDB) suggesting a magmatic origin with minor contributions from biogenic CO2. Comparison with other degassing measurements in the East African Rift shows that records of historical eruptions or unrest do not correspond directly to the magnitude of CO2 flux from volcanic centres, which may instead reflect the current size and characteristics of the subsurface magma reservoir. Interestingly, the integrated CO2 flux from faulted rift basins is reported to be an order of magnitude higher than that from any of the volcanic centres for which CO2 surveys have so far been reported.

Factors Influencing Trainee Career Choice in TVET Institutions in North Rift Kenya

&lt;div&gt;&lt;p&gt;&lt;em&gt;Career choice has always been a very challenging venture for most students in their transition from secondary school to higher learning institutions in most countries. Many factors come to play including self-motivation, influence by peers, parents and even performance in high school examinations. In Kenya, enrolment in market driven courses like engineering and hospitality has remained below capacity despite efforts by the Kenya government to boost it. The main objective of this study was to determine the factors that influenced trainees in their career choice in TVET institutions in North Rift of Kenya with the aim of assisting TVET institutions gain strategies to address skewness witnessed in enrolment in market driven courses. Survey research design was adopted for the study. The population for the study constituted of students and TVET providers in the TVET institutions in North Rift Kenya. Stratified random sampling technique was used to group students into the respective courses undertaken in the TVET institutions and simple random sampling technique was applied to select 316 respondents proportionately from the different strata. Questionnaires were the main research instruments used in the collection of data. Data collected was analyzed using descriptive statistics in SPSS and results presented in tabular and graphical forms. The research findings showed that student’s career choice was influenced by seven main factors. Among the recommendations was that secondary schools should come up with a career sensitization programme each year to help learners be better informed on available careers and current trends in the job market.&lt;/em&gt;&lt;/p&gt;&lt;/div&gt;

The Solanum nigrum Complex (Black Night Shade) Grown in the Rift Valley, Western and Nyanza Provinces of Kenya

The Solanum nigrum Complex (Black Night Shade) Grown in the Rift Valley, Western and Nyanza Provinces of Kenya

Glimmerite-wehrlite xenolith from the ugandite of East African Rift: Mineral composition and conditions of formation

Mantle xenoliths from alkaline volcanic rocks of different geological provinces have been the subject of careful attention and intensive geochemical study during recent decades, as they contain unique information about the deepest zones of the Earth. Mantle xenoliths from the volcanoes of the East African Rift Zone have been most fully explored in the Eastern Branch (Kenya Rift) (Dawson and Smith, 1988; Dawson, 2002; Vauchez et al., 2005; Kaeser et al., 2006). The first studies of xenoliths of the Western Rift Zone was conducted by Lloyd and co-authors (Lloyd and Bailey, 1975; Lloyd, 1981; 1987; Lloyd et al., 1985). Investigations of xenoliths in ultrapotassic rocks from the Western Branch of the Rift—alkaline basalts of the Bufumbiry volcanic field (Barifaijo et al., 2008) and kamafugites from Toro-Ankole province (Link et al., 2008; 2010) have been carried out in recent years. The xenoliths of these two branches of the East African Rift vary in mineral composition—in the volcanic rocks of the Eastern Rift one finds garnet and orthopyroxene, whereas the Western Rift is characterized mainly by pyroxenite xenoliths with rare glimmerite, wehrlites and dunite. This difference is related to the intensity of development processes of mantle metasomatism in the Western Rift, resulting in a greater thickness of the lithosphere. This paper presents the results of a study of the mineral composition of glimmerite-werlithe xenolith and the ugandite phenocrysts from the Bunyaruguru volcanic field. The aim of our study is to show the different stages of alteration of the fertile mantle peridotite: (lherzolite)-wehrlite—glimmerite, based on the example of a single sample. These changes were manifested in gradients of the phase composition and chemical compositions of minerals in the xenolith. GEOLOGICAL SETTING AND PETROGRAPHIC OUTLINE OF THE SAMPLE

Isolation and Characterization of a Thermostable Cellulase from Bacillus licheniformis Strain Vic Isolated from Geothermal Wells in the Kenyan Rift Valley

Cellulolytic microorganisms such as fungi and bacteria are responsible for much of the cellulose degradation in soils. Despite the vast number of cellulase producers, there is a deficiency of microorganisms that can produce significant amount of the three components of a cellulase system. i.e. CMCases, exoglucanases and β-glucosidases to efficiently degrade cellulose to fermentable products. Soil samples were collected from two sites of the Kenyan Rift valley; Hell’s gate National Park and a geothermal well in Eburru hill at depths of 155 m, 156 m and 157 m. Isolation of cellulolytic bacteria was carried out using minimal media supplemented with 1% CMC. Isolates obtained were characterized using both morphological and molecular methods. A quantitative cellulolytic test was carried out to select the isolate with the highest specific activity. Additionally the cell-free supernatant was used for functional studies to determine the isolate’s cellulase system components, optimum temperature, pH and time stability. Phylogenetic analyses indicated that all isolates associated mainly with members of the Bacillus licheniformis. All isolates were capable of utilizing CMC, avicel and Cellobiose as their sole carbon sources. Isolate 3 from a depth of 156 m in the well was identified as Bacillus licheniformis strain vic and selected for further functional studies. This isolate was found to bear the three enzyme components of a cellulase system. A cell free extract was noted to hydrolysecellobiose, Avicel and CMC with enzyme specific activities of 0.46878 U/mg, 0.18784 U/mg and 0.13571 U/mg respectively. Optimum temperature for activity measured over 60 minutes was found to be 60oC with relatively high activity at both 70oC and 80oC. The optimum pH at the predetermined optimum temperature was found to be pH 5. The crude enzyme extract was stable for eight hours of incubation at 60oC and pH 5 retaining 92.2% of its activity. This makes B.licheniformis strain vic a quite attractive isolate for potential application in industries.

Subsurface structure and stratigraphy of the northwest end of the Turkana Basin, Northern Kenya Rift, as revealed by magnetotellurics and gravity joint inversion

In order to understand the subsurface stratigraphy and structure of the northwest end of the Turkana Basin, Northern Kenya Rift, we used 2-D joint inversion of magnetotelluric (MT) and gravity data acquired along 3 profiles perpendicular to the main Murua Rith-Lapur Rift Border Fault. The regional geology is characterized by a basement of Precambrian age overlain by a ≤500-m thick sandstone formation named the Lapur Sandstone of upper Cretaceous-lower Eocene in age, covered by thick rhyolitic and basaltic lavas of late Eocene-middle Miocene age, known as the “Turkana Volcanics”. Final interpretation of the resistivity and density models, until 5 km depth, obtained by the joint inversion approach confirms the previous general knowledge about the half-graben geometry of the northern part of the Turkana Basin. The main Murua Rith-Lapur Rift Border Fault is well identified by both gravity and MT. At least, two other important secondary faults without surface expression are also identified. A new small half-graben basin, named the Kachoda Basin, parallel to the main Turkana Basin and filled by 1.5 km of sediments, has been also characterized. This study also highlights strong thickness variations of the three main geological units that could be expected in the subsurface of the Turkana Basin. For example, the sedimentary Nachukui and Kibish Formations reach up to >3 km in thickness at the eastern end of the north and central profiles. Lateral variations of the topography of the Precambrian basement are also evidenced. Conceptual geological models, which result from the combination of the obtained density and resistivity models as well as from geological and reflection seismic data, are proposed. In such an area of intensive and promising oil exploration, these models are essential in terms of identification of reservoirs, source rocks and trapping mechanisms.

English

Lake Magadi and Little Magadi are saline, alkaline lakes lying in the southern part of Kenyan Rift Valley. Their solutes are supplied by a series of alkaline hot springs with temperatures as high as 86&deg;C. Previous culture-dependent and independent studies have revealed diverse prokaryotic groups adapted to these conditions. However, very few studies have examined the diversity of fungi in these soda lakes. In this study, amplicons of Internal Transcribed Spacer (ITS) region on Total Community DNA using Illumina sequencing were used to explore the fungal community composition within the hot springs. Operational taxonomic units (OTUs) were analyzed using QIIME 1.8.0, taxonomy assigned via BLASTn against SILVA 119 Database and hierarchical clustering was done using R programming software. A total of 334, 394 sequence reads were obtained from which, 151 OTUs were realized at 3% genetic distance. Taxonomic analysis revealed that 80.33% of the OTUs belonged to the Phylum Ascomycota, 11.48% Basidiomycota while the remaining consisted of Chytridiomycota, Glomeromycota and early diverging fungal lineages. The most abundant Ascomycota groups consisted of Aspergillus (18.75%), Stagonospora and Ramularia (6.25% each) in wet sediment at 83.6&deg;C, while Penicillium and Trichocomaceae (14.29% each) were dominant in wet sediment at 45.1&deg;C. The results revealed representatives of thermophilic and alkaliphilic fungi within the hot springs of Lake Magadi and Little Magadi. This suggests their ability to adapt to high alkalinity, temperature and salinity. Key words: Fungi, hot springs, temperature, DNA, diversity.

Groundwater fluoride enrichment in an active rift setting: Central Kenya Rift case study

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 0.02–75mg/L. 73% exceed the health limit (1.5mg/L) in both dry and wet seasons. F− concentrations in rivers are lower (0.2–9.2mg/L) than groundwater (0.09 to 43.6mg/L) while saline lake waters have the highest concentrations (0.27–75mg/L). The higher values are confined to elevations below 2000masl. 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 3750–6000ppm) in minerals such as cordierite and muscovite while secondary minerals like illite and kaolinite have lower remnant fluoride (<1000ppm). 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.

Evaluation of the Factors Controlling Concentration of Non-Condensable Gases and Their Possible Impact on the Performance of Geothermal Systems: Case Study of Olkaria Wells in the Kenyan Rift Valley

The Olkaria geothermal field is located in the Kenyan Rift valley, about 120 km from Nairobi. Development of geothermal resources in the Olkaria area, a high temperature field, started in the early 1950s. In the subsequent years numerous expansions have been carried out with additional power plants being installed in Olkaria. These include a binary plant at Olkaria South West (Olkaria III) in 2000, a condensing plant at Olkaria North East (Olkaria II) in 2003, another binary plant at Olkaria North West (Oserian) in 2004 and finally condensing plants in the year 2014 within East production field (EPF) and Olkaria Domes (OD) areas. The total generation from this field is about 730 Mw. The study considered samples from 4 producing wells from 3 fields of the Olkaria geothermal area (OW-44 from the Olkaria East, OW-724A from the Olkaria North East, and OW-914 and OW-915 from the Olkaria Domes field). The chemical data were first analyzed using SOLVEQ. This helped in the determination of the equilibrium state of the system, the reservoir temperatures and the total moles to be run through CHILLER. The run CHILLER considered the processes that have been proven to be occurring in the Olkaria field i.e., boiling and condensing processes, fluid-fluid mixing rocks and titration resulting from water-rock interaction. The effects on gas evolution were evaluated based on the resulting recalculated gas pressures. The results indicate that the gas species are not in equilibrium with the mineral assemblages. The CHILLER evaluation shows boiling as the major process leading to the evolution of gases. OW-44 had the least gas concentrations, arising from the considered reservoir processes due to degassing, and near surface boiling, besides the removal of NH3, H2 and H2S are through the reaction with steam condensate. The gas breakout is most likely in OW-914 and least in OW-44. The study proposes different reservoir management strategies for the different parts of the Olkaria geothermal field. That is by increasing hot reinjection in the eastern sector around well OW-44. The reservoir around OW-914 is to be managed by operating the wells at a minimum flow rate (or even to close them) or the use of chemical inhibitors to prevent calcite scaling.

Current Status of Grevy Zebra: A Review

Grevy’s zebra is a member of the horse family, equidae, and so is closely related to horses; asses and other zebra inhabit dry desert regions and open grasslands. Grevy’s zebra is one of the world’s most threatened wild equids and is IUCN red-listed as endangered. Historically, the Grevy’s zebra Equus grevyi ranged from east of the rift valley in Kenya to Western Somalia and Northern Ethiopia. Now a days, Grevy’s zebra found only in Kenya and small isolated populations in Yabello Sanctuary park in Ethiopia. They are regionally extinct in Djibouti, Eritrea and Somalia The number of Equus grevyi has declined rapidly by 85% over the last 27 years in the late 1970s the number estimates to be 15,000 but the current estimation is between 1,700 and 2,100. The species of Grevy’s zebra are on verge of extinction due to habitat degradation and loss, competition for resources with livestock, hunting, drought, disease, hybridisation and predation. Therefore, routine conservation strategies should be implemented as soon as possible.