PHYTOPLANKTON COMPOSITION OF A SHALLOW AFRICAN TROPICAL RESERVOIR (ADZOPÉ, CÔTE D’IVOIRE)

Abstract

Phytoplankton of the Adzopé reservoir was investigated from May 2008 to February 2009. Samples were taken seasonally from 4 sampling stations. A total of 212 taxa belonging to 6 divisions have been identified, including Chlorophyta (35.38 % of taxa), Euglenophyta (29.25 %), Bacillariophyta (18.40 %), Cyanoprocaryota (10.85 %), Xanthophyta (5.19 %) and Pyrrhophyta (2.36 %). The greatest species richness was found in the central zone at S3 (205 taxa) and the smallest was recorded in the upper zone at station S1 (165 taxa). In the remaining stations were collected 173 (S2) and 195 (S4) taxa. At all the stations, the phytoplankton community was typically dominated by the pelagic-benthic species of Bacillariophyta (17 taxa) and pelagic species of Euglenophyta (43 taxa) and Chlorophyta (41 taxa). Spatio-temporal patterns of phytoplankton groups showed that Euglenophyta and Chlorophyta were permanent groups whatever the stations and seasons except stations S1 and S2 in long rainy season, where Chlorophyta accounted for 9.1 and 12.5 % of sporadic taxa respectively.