SEASONAL ECOLOGY OF HYDROCARBON-UTILIZING MICROBES IN THE SURFACE WATERS OF A RIVER

Seasonal changes in the microbial communities of the New Calabar River water have been investigated. Analyses of the BOD, pH, salinity, oil a nd grease levels of effluents of industries sited along the river were also conducted. High hydrocarbon-utilizing microbial populations were found. The percentage of hydrocarbon-utilizing heterotrophic bacteria ranged between 0-98% and 0-68% in the rainy and dry months, respectiv ely. Counts of hydrocarbon-utilizing actinomycetes in the rainy months ranged between 0-95% and 2-55% in the dry months. The hydrocarbon-uti lizing yeast population ranged between 1-95% and 2-85% for the rainy a nd dry months, respectively. Rainy month values for hydrocarbon-utiliz ing mould population ranged from 0-17% while dry month values ranged f rom 0-47%. The hydrocarbon-utilizing cyanobacterial population ranged between 0-95% and 0-33% in the rainy and dry months, respectively. Our results suggest that the heterotrophic bacterial and cyanobacterial p opulations are higher in the rainy months than in the dry months. Howe ver, the hydrocarbon-utilizing yeast, mould and actinomycete populatio ns did not show seasonal variation.