Growth and corallite characteristics of Kenyan scleractinian corals under the influence of sediment discharge

Disturbances of terrestrial origin are important determinants in the growth, carbonate production and well- being coral reefs. In this study, coral growth (density, linear extension and calcification rates) and corallite (diameter and density) variables were determined for selected species from four Kenyan protected reef lagoons, with one receiving a pulse of sediment discharge. Variable coral growth responses were observed, with some species showing higher growth rates while others exhibited low growth rates within the sediment impacted reef. Species corallite characteristics also showed variable responses, though corallite diameters were found to be larger in the sediment impacted reef with low corallite densities generally being observed in the mangrove-fringed reef. Coral bulk density was found to be poorly correlated to calcification and extension rate but calcification and extension rates were found to be highly correlated (R values 0.84 to 0.98). The variable responses observed in the current study have important implications and applications in coral reef health and management by providing information on the susceptibility of different corals species to local stressors, and together with coral distribution and composition data this information may be useful in the formulation of suitable and scientific based reef management strategies and also in predicting reef performance under future climate change scenarios.   Key words: Calcification, corals, climate change, density, linear extension, sediments, terrestrial disturbances.