An Assessment of Nutrient Loading, Eutrophication and Plankton Dynamics in three Marine Tidal Creeks, Kenya: Port Reitz, Mtwapa Creek And Funzi Bay.

Abstract

Coastal marine eutrophication is recognised as a worldwide problem. On a global scale, it is now estimated that the input of nutrients especially various forms of nitrogen and phosphorus, to marine ecosystems from human sources via rivers are equal to or greater than, the natural input. The proposed study aims at assessing the eutrophication status of creeks to determine effects of nutrient loading on these ecosystems. This aim will be achieved by assessing the forms, concentrations and ratios of nitrogen and phosphorous as principal nutrients and how they affect rates of production and both phytoplankton and zooplankton compositions. The creeks have been chosen due to differences in nutrient loading. Port Reitz and Mtwapa creeks will be compared to Funzi bay, a relative pristine ecosystem. Sampling in these areas will be done taking into consideration, both point and non-point sources of anthropogenic nutrient loading. Physico-chemical parameters that will be analysed at each site include temperature, conductivity, dissolved oxygen and salinity. The various forms and concentrations of Nitrogen and Phosphorous will be analysed using various methods described for the analysis of nutrients in tropical seawater. Various phytoplankton and zooplankton compositions will be counted and analysed statistically using the Shannon-weaver method. The effects of nutrients on primary production, phytoplankton and zooplankton abundance will be determined in a bid to assess eutrophication and nutrient loading effects to productivity of these ecosystems. The information obtained during this study shall contribute significantly to the formulation of pollution/eutrophication control procedures as well as a basis for future research.