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"Reef relief" -- The Discovery Files

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A study by Oregon State University researchers to test the impact of nutrient loading on coral reefs has confirmed that this type of pollution from sewage and agricultural practices can lead to coral disease and bleaching.

Credit: NSF/Karson Productions

Audio Transcript:

(Sound effect: Surf sound) Good reef!

I'm Bob Karson with the discovery files--new advances in science and engineering from the National Science Foundation.

(Sound effect: underwater sounds) Coral reefs are a key to biodiversity in tropical waters hosting thousands of species of fish and other marine life. They've taken a serious hit lately. In just a few decades, some 80% of Caribbean corals have disappeared. A comprehensive 3-year study from Oregon State, Florida International University and University of Florida looked at the impact of "nutrient loading" the introduction of specific pollutants common in sewage and fertilizer runoff.

(Sound effect: underwater, scuba sounds) The study site was in the Florida Keys, where the team exposed corals to controlled, elevated amounts of nitrogen and phosphorus. It was not a pretty picture. An early sign of stress, coral "bleaching" tripled. By the end of the 36-month experiment, the prevalence of disease doubled. This from a level of these pollutants common in areas affected by sewage discharge or fertilizers from agricultural or urban use.

This is one of the first long-term studies to isolate the impact of nutrient overloads from other causes of reef decline.

The team's findings also show it's not all gloom and doom. They noted the reefs made a strong recovery within ten months after the nutrient loading stopped. Ah, reef relief.

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research--brought to you, by you! Learn more at or on our podcast.

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