Octocorals as indicators of anthropogenic nutrients

<p>Coastal ecosystems are influenced by anthropogenic nutrients. Increased nutrient loading has not been directly linked to the source of the nutrients because of the inadequacies of current nutrient sampling methods. I propose to use N stable isotope analysis of octocorals as proxies of environmental N availability. Gorgonia ventalina collected on reefs surrounding San Salvador, Bahamas have significantly different delta15N consistent with human impacts. Octocoral within the family Gorgoniidae have similar delta15N within sites; thus species within a family may be used interchangeably. Depth has a significant influence on delta 15N. Pseudopterogorgia americana collected over a 9 m range varied by ∼1.25‰ (r2 = 0.5453). This study has shown that octocorals provide reef-to-reef variation in delta 15N consistent with human impact at these reefs, thus they are a good proxy for anthropogenic nutrients.</p>