Water quality assessments: A case study of plankton and macrobenthic invertebrates of Porto-Novo and parts of Gulf of Guinea

Abstract

Aspects of physico-chemical characteristics, plankton and macro invertebrates of Porto-Novo and Gulf of Guinea were studied in September 2012 with a view to determine the quality of water using plankton indices. Standard methods were used to determine the physico-chemical parameters. The mean water quality parameters studied were temperature (36.71^oC), pH (7.63), transparency (1.97m), total dissolved solids (10.0mg/L), dissolved oxygen (4.73mg/L) and salinity (38.58‰) for Gulf of Guinea. Five divisions; Cyanophyta, Bacillariophyta, Chlorophyta, Euglenophyta and Pyrrhophyta were recorded for both bodies of water with diatoms and dinoflagellates dominating the spectrum. The phytoplankton ofPorto-Novo recorded abundance of Gomphonema spp., Fragilaria crotonensis, Synedrasp. and Nitzschia sp.(diatoms) while that of Gulf of Guinea recorded Ceratium spp. and Gonyaulax spinifera (dinoflagellates). For the zooplankton, Acartia clausii (a copepod) and Penilla avirostris Dana (Cladocera) were the highest in both occurrence and abundance especially at Porto-Novo. The population of benthic fauna was low (20 individuals) dominated by bivalve, Tivela tripla.

Keywords: Microalgae, zooplankton, benthos, Porto-Novo, Gulf of Guinea