Browsing by Author "Jomo, Boston"

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  • Publication
    Publication
    Characteristic Relationships between Phosphorous Accrual, Ecosystem Aspects and Water Level Fluctuations in Tropical Lakes: Naivasha Ramsar Site, Kenya
    (Scientific Research, 2021-01) Obegi, Beatrice; Ogendi, George; Omondi, Reuben; Jomo, Boston; Morara, George; Rindoria, Nehemiah; Orina, Sagwe
    Hydrological dynamics affect water levels and thus affecting ecosystem structure and functions. Lake levels in tropical ecosystems affect phosphorous input through runoff from adjacent watersheds. The resultant biological community, water and sediment quality of the lakes due to water level changes is a reflection of the geology of the area and the anthropogenic activities in the watershed. The study conducted between January 2018 and December 2019 was to explore relationships between the phosphorous input and Water Level Fluctuations (WLF) recorded by Water Resource Authority (WRA). Lake water samples were analyzed in the laboratory for phosphorous using molybdenum blue-ascorbic method and recorded using spectrophotometer. Chlorophyll-a was determined by extracting a filtered sample with 15 ml acetone and incubating overnight and thereafter read using a double beam spectrophotometer. Total Suspended Solids (TSS) was determined by filtering 200 ml of a water sample and dried overnight at 105°C. The lowest and highest phosphorous concentrations recorded were 0.2 mg/l and 0.42 mg/l at NST7 and NST2, respectively. Measurements of Chlorophyll-a were 0.32 mg/l and 0.42 mg/l at NST9 and NST2, respectively. Secchi transparency measurements were 32.9 cm at NST3 and 84 cm at NST1. The highest and lowest TSS concentrations were 0.14 mg/l and 0.13 mg/l at NTS1 and NST8, respectively. The hydrodynamic regime in most tropical lakes plays a significant role in the re-reaction of phosphorous that consequently influences productivity. Tropical lakes have extreme lake level fluctuations which accelerate the production process. The influence of water level changes on aquatic productivity is crucial in most tropical lakes and should be taken into consideration when assessing the environmental impacts.
  • Publication
    Publication
    Spatial variation in diversity, distribution, and abundance of macroinvertebrates and their response to physicochemical param- eters in River Nyakomisaro, kisii-Kenya
    (IJTHF, 2020-02-20) Jomo, Boston; Omondi, Reuben; Getabu, Albert; Orwa, Patrick
    Aquatic animal and plant diversity of tropical aquatic ecosystems are severely threatened by frequent anthropogenic activities. The study investigated spatial variation in macroinvertebrate community and physicochemical parameters of River Nyakomisaro from July to December 2016. Five sampling sites were selected and a pool, a ri󰀪e and a run identied in each site for sampling. Kick sampling was employed in collecting macroinvertebrate samples while selected physicochemical parameters were determined in situ using a water quality multi-parameter meter model 85–15 ft YS1. A total of 6,104 macroinvertebrates belonging to 30 genera, 22 families and 10 orders were recorded. The highest diversity (2.719 ± 0.018) was recorded in station 1 while station 5 had the lowest diversity (1.229 ± 0.026). The highest abundance was recorded in station 5 with 1,948 macroinvertebrates dominated by Chironomids which are highly tolerant to perturbations while station 1 recorded the lowest abundance of 473 macroinvertebrates and dominated by macroinvertebrate communities that are sensitive to environmental pollution. Analysis of variance (ANOVA) showed signicant di󰀨erences (p<0.05) in diversity, abundance, and distribution of macroinvertebrates of River Nyakomisaro. Headwater stations had taxa that thrive in undisturbed waters with a reduction of genera that are sensitive to perturbations such as Ephemeroptera, Plecoptera, and Trichoptera in downstream stations. This was a clear indication of pollution of the waters downstream. This response makes macroinvertebrate communities in River Nyakomisaro good bio-indicators of water quality. Therefore, the ndings of the current study can form a basis for the establishment of strategies for conservation, protection, and restoration of macroinvertebrates and the integrity of river Nyakomisar