Phytoplankton community response to increase petroleum hydrocarbon in Niger delta estuaries, southern Nigeria. – I. Ewa-Oboho, O. Oladimeji, F. E. Asuquo1and E. I. Oboho
Phytoplankton communities from eight estuaries of the Niger delta (S. Nigeria) covering a range of oil and grease (total hydrocarbon content – THC) from 2.26 to 38.82 ppm, were studied during 1998-2000 and compared to data from experimentally (simulated) oiled estuarine embankment in Abonnema – near Port Harcourt, to assess recovery from oiling effects. Based on historical data, total Hydrocarbon Content levels have increased in several of the estuaries. Phytoplankton biomass did not correlate with total hydrocarbon content, but there was a high significant relationship between species richness and total hydrocarbon content. Recovery from oiling were observed in some estuaries, combining species diversity data from the present study with historical data. Correspondence analysis indicated that some of the estuaries that experienced increase total hydrocarbon content have shifted toward phytoplankton assemblages typical of non-oiled estuarine environment.