Effects of wave energy, topographic relief and sediment transport on the distribution of shallow-water gorgonians of Puerto Rico

Abstract

Environmental factors controlling the distribution of shallow-water gorgonians of Puerto Rico were inferred from a Reciprocal Averaging ordination analysis. The data set included several samples taken before and after the passage of Hurricane David and the mass mortality of the sea urchin Diadema antillarum. We could infer only a single environmental gradient associated with the distribution of gorgonians. Stations at opposite extremes of this gradient were characterized by combinations of high wave action with low topographic relief, or low wave action with high topographic relief. This gradient was also associated with sediment transport across the bottom (bedload). A detailed examination of ordination results in relation to Hurricane David and the Diadema mortality indicated that sediment transport, rather than water movement and topographic relief, is more directly related to the distribution of shallow-water gorgonians.