Preliminary study on phytoplankton and nutrients status of Oya Lake, Bayelsa State, Nigeria

Abstract

Oya Lake located along Taylor Creek in Ikarama Community in Yenagoa Local Government Area of Bayelsa State is a dump for various domestic and industrial wastes especially oil spills from its surroundings. A preliminary study was conducted to evaluate the taxa, species composition, diversity, abundance and distribution of phytoplankton as well as nutrient status of this Lake. Phytoplankton and surface water samples for nutrient analysis were collected during the dry months of the year (November-December 2014 and January 2015) from ten sampling stations according to APHA method. A total of four hundred and twenty (420) phytoplanktons from three (3) families, eight (8) genera and eleven (11) species were identified. The three families were Bacillariophyceae (13.1%), Euglenophyceae (13.1%) and Chlorophyceae (73.8%). Chlorophyceae were dominant in terms of species composition and abundance. The mean value of phosphate (0.21 ± 0.07 mg/L) was above the USEPA permissible limit of 0.1 mg/L. The presence of dominant Chlorophyceae, low species composition, diversity, abundance and distribution of phytoplankton as well as high value of phosphate denotes that Oya Lake is perturbed and organically polluted. Also, the observed Melosira distans and M. granulata indicates nutrient (phosphate) enrichment of Oya Lake.