ABSTRACT
The current research assessed the species composition, relative abundance, monthly fluctuation and biodiversity index of Phytoplankton in Mala River water in Argungu Town, Kebbi State, Nigeria.
Collection of samples commenced from January to August, 2018. Three sampling sites were chosen from the river (Upper-stream, Mid-stream and Down-stream). Phytoplankton samples were collected from the
sites and analyzed in the laboratory using standard protocol. Phytoplankton abundance and species
diversity were determined by using Margalef, Evenness and Shannon index. This study identified 4
families of phytoplankton which include Bacillariophyceae, Chlorophyceae, Cyanophyceae and
Euglenophyceae. Bacillariophyceae is the most dominant with the highest species composition of 3083 with relative abundance of 42%. It showed the total number of 22 different phytoplankton species. Highest composition was obtained in Navicula digitoradiata with 1744. While least composition was obtained on Nitzchia acicularis, Turballaria fenestrate, Scenedesmus brasiliensis, Nitella brittlewort,
Aphanocaps ricularis, and Glococapsa punctata with 13 composition each. It further revealed that,
relative abundance of phytoplankton in Mala River depend on monthly fluctuation and sampling stations. Furthermore, results indicated that, highest relative abundance of phytoplankton was obtained at the midstream of the river in March (71.43%), February (66.67%), and August (66.67%). While least relative abundance of phytoplankton was obtained at down-stream in February, March, June and August with no phytoplankton during those periods. Great biodiversity of phytoplankton in the study site and the
species are evenly distributed. Further studies on physicochemical parameters and toxicological analysis
of the Mala River are hereby recommended. The State Ministries of Water Resources and Environment
should set up appropriate monitoring and controlling units to regulate sewage discharge into the river.