The Effect of Crude Oil Spill on Plankton Abundance in Santa Barbara River, Nembe, Bayelsa State

Plankton are the main varied group of aquatic organisms that play major roles in the aquatic environment as primary producers. The study focused on the effect of crude oil Spill on Plankton composition in Santa Barbara River, Nembe, Bayelsa State. Samples were collected and preserved in 5% formalin from ten (10) water sampling locations with one serving as control in four replicates. Standard plankton net of 55 m mesh size was used for sample collection. Data recovered from the study showed the occurrence of 61 species of plankton belonging to two (2) classes, 8 families and genera. A total of 486 organisms were recovered from the surface water out of which 394 (81.06%) were phytoplankton and 92 (18.93%) were zooplankton. The families of planktons identified were Bacillariophyceae, Cyanophyceae, Chlorophyceae, Xanthophyceae, Euglenophyceae, Dinophyceae, Copepod, and Cladocera. The family Bacillariophyceae had the highest species diversity (144) within WO/SW1 having the highest species richness of (96) which represented (19.75%) of the total plankton population recovered in the study. Sampling station WO/SW2 had a species richness of 64 (13.16%) while BA/SW8 had the lowest species richness of 32 representing (6.58%) of the recovered plankton population in the study. The result shows a decrease in the distribution and abundance of the plankton species in the Santa Barbra River. The results indicate pollution caused by hydrocarbon spillage. There was phytoplankton bloom when compared to zooplankton. The zooplanktons were more sensitive to the hydrocarbon spill than phytoplanktons this is linked to hypoxic nature of surface water following the hydrocarbon spill incident significantly affecting zooplankton abundance and diversity in the Santa Babra River.