Journal d'océanographie et de recherche marine
Libre accès

Abstrait

Current Patterns in Intertidal Macro-Algal Diversity and Zonation of Two Sites on Ghana’s Coast

Gbedemah ST

In this study, the various floral species of two sites were surveyed for Macroalgal composition and floral zonation. No such study has been conducted for specific Ghanaian rocky shores such as Prampram and Takoradi, although more generalized studies are available concerning the coastal ecology of Ghana as a whole. Quadrat sampling was done to determine floral composition and distribution. Floral zonation was studied to investigate a discernable gradient in ecological health. The study focused on two similar rocky intertidal areas, 230 km apart, at Takoradi and Prampram, both in Ghana. Four belt transects were randomly laid from the lower to upper shores of each site and along which a continuous quadrat (1 m2) was placed to estimate species percentage cover (macroalgae). The species data was standardized before submitted to statistical analyses. Also two replicate water samples were taken at each site for the analyses of nutrients (i.e., nitrate and phosphate). Altogether a total of 36 species of macroalgae, comprising 9 Chlorophyta, 10 Phaeophyta, and 17 Rhodophyta were identified as present at both locations during the study. A multivariate analyses of the abundance and location of macroalgae in relationship to their level in the intertidal zone detected zonation differences in the macroalgal community structure between the western and eastern locations at Takoradi and Prampram respectively. It was observed that Rhodophyte species were more diverse in general than the other taxa at both sites. For Shannon-Wiener diversity, it is observed that samples for Takoradi are more diverse than Prampram. Species within algal taxa Rhodophyta are most abundant at both sites with Chlorophytes coming in next. The relative abundance for both Rhodophytes and Chlorophytes sampled from Prampram is higher than those from Takoradi. Phaeophytes at the other hand are higher in Takoradi than in Prampram. Polycavenosa dentata/ Hydropuntia rangiferina was the most abundant species occurring in the wet and dry periods. These observations provide a basis for future studies in determining conservation strategies for Prampram which is a fishing hub and Takoradi an industrialized city.