Carbonate Chemistry and Structure of Macro-invertebrate Communities in Relation to Organic Pollution in the Coastal Atlantic Ocean at Kribi (Cameroon)

摘要

Background and Objective: In tropical Africa, the chemistry of carbonates in coastal waters has been little studied, which does not predict ocean acidification and its impact on the viability of coastal ecosystems. In this study, the variability of the carbonate system and the structure of macro-invertebrate communities in relation to organic pollution in the coastal Atlantic Ocean at Kribi in Cameroon are described for the 1st time. Materials and Methods: Macro-invertebrates were sampled monthly over a 3 months period (May to July, 2018) using the quadrant method, in three stations. Measurements of the physicochemical variables (nutrients, pH, salinity, temperature, total alkalinity and dissolved oxygen ) were done simultaneously. Carbonate system parameters were calculated using the COsub2/sub cal software V4.0.9. Results: The organic pollution index (OPI) has shown that the coastal waters of Kribi are subject to heavy organic pollution. The values of the parameters of the carbonate system indicate that the coastal ocean at Kribi is not subject to acidification. Also, the saturation rates of aragonite and calcite are greater than 1. The pH is alkaline, 8.02. The Shannon and Weaver (1.87-2.87) and Piélou (0.59-0.69) indices indicate poorly diversified stands of macro-invertebrates, numerically dominated at each site by two or three species and characterizing disturbed intertidal ecosystems. Conclusion: This study made it possible to show through the positive and significant correlation between pH and OPI, that organic pollution of coastal waters is a precursor to the acidification phenomenon, the consequences of which are disastrous for biodiversity.