Nutrient pollution can exacerbate coral disease outbreaks and threatens coral reef health

Wildlife diseases are one of the primary threats to coral reefs and other endangered marine ecosystems. For example, fungal and bacterial infections of reef-building corals and other key species recently caused mass-mortalities throughout the Caribbean.

Species that dominated Caribbean coral reefs only twenty years ago are now functionally extinct. Little is know about the factors that promote marine diseases, but it is suspected that human activities have altered the environment, subsequently promoting disease epidemics and coral die offs.

In the December issue of Ecology Letters, Bruno, Petes, Harvell, and Hettinger report that nutrient pollution can increase the severity of coral diseases. The research team performed field experiments on Mexican reefs off the Yucatan Peninsula, currently threatened by coastal development. Their results indicate that even modest nutrient pollution can increase the mortality of three important Caribbean corals by facilitating disease spread.

This research suggests that further steps should be taken to reduce nutrient pollution from sources including agricultural runoff, sewage pollution, and deforestation.

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