Phytoplankton community structure and ecology in Lake Naivasha, Kenya

Abstract

The phytoplankton community structure and ecology of L. Naivasha was studied for a period of six months on a monthly basis between February 2019 and July 2019. The main objective was to determine the phytoplankton species diversity, distribution, and abundance from the seven sampling points in L. Naivasha. A total of one hundred and twenty four (124) species belonging to six (6) taxonomic group were identified. Chlorophyceae was represented by 43 species consisting of 34.68% by species composition, Bacillariophyceae was represented by 38 species consisting of 30.65% by species composition. Cyanophyceae was represented by 24 species leading to 19.35% species composition. Other taxonomic groups included Zygnematophyceae, Euglenophyceae, and Dinophyceae represented by 9 (7.26%), 7 (5.65%) and 3 (2.42%) species respectively. Cyanophyceae recorded the highest abundance in cells/litre, followed by Chlorophyceae and Bacillariophyceae. The total number of algal species was highest in Hippo point with 72 (16.59%) species, followed closely by 68 (15.67%) species in Crescent Island, followed by 66 (15.21%) species in Oserian Bay. Mouth of R. Malewa recorded 59 (13.59%) species, Sher Bay had 58 (13.36%) species, this was followed by Mid Lake station with 56 (12.90%) species, and Sewage Discharge Point had 55 (12.67%) species. Shannon-wiener diversity (H) index ranged from 2.0455 (Mouth of R. Malewa) to 2.7077 (Oserian Bay). In conclusion, Lake Naivasha depicted a higher diversity of phytoplankton species. Results from this study showed the state of L. Naivasha trophic status based on phytoplankton ecology.