Tidal Influence on Epiphyton Population of Okpoka Creek, Upper Bonny Estuary, Nigeria

Abstract. Okpoka Creek of the Upper Bonny Estuary in the Niger Delta is a sink under tidal effects. The study investigated the influence of low and high tides on the species composition, diversity, abundance and distribution of epiphyton. The epiphyton samples were collected monthly from May 2004?April 2006 at both tides from ten stations according to APHA methods. Epiphyton was identified microscopically. Species diversity was calculated using standard indices. Data analyses were done using analysis of variance, Duncan multiple range and descriptive statistics. Phosphate and ammonia exceeded FEPA and USEPA acceptable levels (0.10 mg/L and 0.10 mg/L respectively) for natural water bodies. Phosphate had significant tidal variations (P