Post Flood Impact on the Diversity, Abundance and Distribution of Phytoplankton in River-Nun, at Amassoma, Niger Delta, Nigeria

Global warming and Climate change have resulted in perennial floods in the Niger Delta. As floods recede, they do so with land-based pollutants which affect aquatic biota. Phytoplanktons are greatly affected by pollutants resulting in the reduction and distortion of their diversity, distribution and abundance. Hence this study was undertaken to gauge the damage of flooding on phytoplankton and the ecosystem. Four (4) sampling were identified and phytoplankton samples collected in triplicates using plastic containers and fixed with 4% formalin. Identification of samples were done in the Laboratory of the Niger Delta University using standard identification keys. Result showed the presence of twenty seven (27) species of phytoplankton which are Coscinodiscus stellaris, Synedra sp., Melorisn sp., Pseudo-nitzrchia pungers, Thalassion erna nitzsthioides, Tabellaria sp., Tabellaria fenestrata, Epithemia sp., Pseudo-nitzrchiea australis, and Melorisa undulata Microcystis aeruginosa, Calochrix sp. Draparnaldia sp., Closteriopsis longissima, Cladophora crispate, Mougeotia sp., Closterium juncidum, Microspora sp., Closterium gracile, Cladophora glomorata, Zygnema sp., Trachelomonas sp., Trachelomonas tamboweica, Euglena sp., Lamanea sp. Tribonema sp., Vanchoria sp. from six divisions (Cyanophyta, Bacillariophyta, Chlorophyta. Euglenophyta, Rhodophyta, and Xanthophyta.). Data analysis reveal that Shannon diversity index was highest in Station 3 (2.34) followed by Station 1 (2.16), and Station 4 (2.04) and lastly Station 2 (0.64). Simpson’s Index was lowest in Station 3 (0.07), followed by Stations 2 (0.54), Stations 1 (0.12) and lastly Station 4 (0.16). There were major changes and variations occurring in phytoplankton communities in the different stations. This indicate that flooding has a marked negative influence on phytoplankton dynamics as all the measured parameters show spatial variations.