Gabche¹, C.E., and V.S. Smith²

¹IRAD – Fisheries and Marine Sciences Research Station, Batoke, P.M.B. 77 Limbe, South West Province, Cameroon, Tel: 237-333.20.71/775.89.03, Fax: 237-333.23.76/333.20.25 , E-mail: cemenegab@yahoo.com and ²Department of Oceanography, University of Hawaii, U.S.A.

Water, salt and nutrients budgets of two estuaries in the coastal zone of Cameroon

This paper presents a biogeochemical model of water, salt and nutrient budgets for two estuarine systems within Cameroon’s coastal zone (Latitudes 2-13 ⁰N; Longitudes 2-16⁰E) of sub-Sahara Africa. These will provide the opportunity to characterize terrigeneous inputs from natural and anthropogenic influences and outputs with net determination of the role of the estuarine zone as a sink for nutrients (Nitrogen (N) and Phosphorus (P)) within the coastal zone, estuaries and adjacent ocean. Data requirements for the budgets included a detailed description of the estuarine systems (Cameroon estuary = Longitude 9.25 – 10.00E+; Latitudes 3.83 – 4.1N+ considered as a pollution ‘hot spot’ and the Rio-del-Rey estuary Longitude 8.3E+; Latitude 4.8N+ considered as a relatively similar but less polluted area). Others include the salinity of the systems and adjacent ocean, volume of fresh water input and output, concentration of nutrients for systems, adjacent ocean, fresh water and other sinks and sources. Hydrological data used included river discharge, rainfall and evaporation obtained from Cameroon’s meteorological service, government sources and research. Modeling methodology was according to the Land Oceans Interaction in the Coastal Zone (LOICZ) biogeochemical budgeting guidelines (Gordon et al, 1996; http://data.ecology.su.se/MNODE/; Smith et al 1997 and Computer Assisted Budget Analysis, Research, Education and Training (CABARET) note. For two seasons, one layered and one box model were developed for the estuarine systems considered to be completely mixed. Other budget estimates are given on the Dissolved Inorganic Phosphate (DIP) and Nitrogen (DIN), non-conservative materials and stoichiometric calculations of aspects of net metabolism. These results are compared to those of other estuarine systems of sub-Saharan Africa and similar regions of the world. The results gave indications of the level of eutrophication of coastal and ocean ecosystems and degree of impacts on aquatic living resources (e.g., fish species and their food within the ecosystems). Mitigation strategies and measures are proposed for the future.