Browsing by Author "Mwaguni Saeed"

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    Effect of Selected Environmental factors on Microalgae Diversity and Abundance in Gazi Bay, South Coast Kenya
    (Journal Of Sea Research, 2022-06) Swaleh Miriam; Abubakar Laila; Mwaguni Saeed; Munga Daniel; Okuku Erik; Dzoga Mumini; Fulanda Alexander
    Abstract Microalgal community structure of Gazi Bay, Kenya and association with environmental factors was studied between February, June 2019 and October 2020. Non-Metric Multidimensional Scaling (NMDS) and the Rarefaction curves were used for the analysis of community structure; while Principal Component Analysis (PCA) was used to determine correlation between environmental factors with abundance and species diversity of microalgae. A total of 79 microalgae species belonging to 10 classes were recorded, with diatoms dominating in all the sampling sites. The three most abundant species of microalgae observed were Scripssiela sp, Peridinium quinqeucorne, and Striatella sp. There was temporal and spatial distribution of microalgae in the study area. Microalgae abundance ranged from 942 cells/L to 14,990 cells/L, with the highest mean abundance recorded in February during the dry season. Western creek indicated the highest abundance and species diversity compared to other stations at the bay with a significant difference in sample compositions (R = 0.236, P = 0.002). Pearson correlation coefficient showed that the environmental parameters; Total Dissolved Substances (0.61) and salinity (0.59) had a positive correlation with microalgae abundance. This relationship was significant at p < 0.05 for N = 12. In addition, these parameters had a strong influence on microalgae composition and abundance in the Western creek at Gazi Bay. While the microalgae in Mapononi and Doa were influenced by nitrate levels and pH respectively. Gazi Bay is recognized as an important breeding site for fisheries in the south coast of Kenya. Therefore, our findings may be useful in identifying areas within the bay that may be conserved in order to sustain the coastal community livelihood, and justify effective management of hinterland activities to minimize eutrophication.
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    The Potential of Marine micro-algae grown in Wastewater to remove Nutrients and Produce Biomass
    (Kenya Aquatica Journal, 2022-06) Swaleh Mariam; Abubakar Laila; Mwaguni Saeed; Munga Daniel; Okuku Erik
    Abstract Wastewater is a free source of nutrients for microalgae cultivation as it offers an opportunity to produce biofuel hence, significantly lowering their production costs. Microalgae was cultured in wastewater to determine the optimal condition for nutrients removal and production of low-cost biomass. Three different microalgal cultures containing cyanobacteria (Oscillatoria sp.), chlorophyte (Chlorella sp.) and diatoms (Entomoneis sp.) were cultivated in various mixtures of wastewater in seawater, ranging from 0% to 60% volume by volume (v/v). A significant difference (p˂0.05) was recorded between the concentration of phosphates and nitrates before and after the experimental period for all the cultures. Removal of phosphates in the wastewater cultures dominated by Oscillatoria, Entomoneis and Chlorella ranged between 25.4%-86.3%, 14%-100% and 85.7%-100% respectively, while removal of nitrates ranged between 7.5%-64.8%, 8.5%-64.1% and 4.0-67.6% respectively. A significant difference (p˂0.05) was also recorded in the microalgae growth for the different wastewater concentrations. The cultures dominated with Chlorella showed highest biomass production at 60% wastewater concentration, while cultures with Entomoneis and Oscillatoria had highest productivity at 20% wastewater concentration. Seemingly, the optimal conditions of wastewater treatment and biomass production of microalgae depends on the species and nutrient availability.