IMPACT OF SOME HYDROLOGICAL FACTORS ON PHYTOPLANKTON COMMUNITY STRUCTURES IN AGAIE-LAPAI DAM RESERVOIR OF NIGER STATE, NIGERIA

Abstract

The impact of some hydrological factors (rainfall, inflow and depth of water) on phytoplankton, biodiversity in Agaie – Lapai dam reservoir were studied by monthly sampling and measurements taken from May, 2013 to October, 2014. This reservoir is situated at 9° 39’ N latitudes and 6° 33’ E longitudes. The reservoir is near Bakaje village at the confluence of the River Jatan and two other rivers the Jimada and Chemi. Samples of phytoplankton were collected with plankton net of 50um mesh size in designed stations within the reservoir. Seven (7) phytoplankton taxa identified during the study belonging to Chrysophyta (with 99 spp), Bacillariophyta (104 spp). Chlrophyta (with 196 spp), Cyanophyta (with 21 spp). Euglenophyta (with 93 spp), Pyrophya (with 33 spp) and Cryptophyta (with 35 spp). The hightest level of impact rainfall was corrected by the phytoplankton from the month of November to December. Cryptophya recorded the highest respond while other phytoplankton taxa showed increase or decrease in the first and second seasons respectively. The Bacillariophyta and Euglenophyta taxa did not respond to the fall and rise of rainfall level while other phytoplankton taxa were significantly correlated by the rainfall.