One of the largest and longest experiments ever done to test the impact of nutrient loading on coral reefs today confirmed what scientists have long suspected — that this type of pollution from sewage, agricultural practices or other sources can lead to coral disease and bleaching. A three-year, controlled exposure of corals to elevated levels of nitrogen and phosphorus at a study site in the Florida Keys, done from 2009-12, showed that the prevalence of disease doubled and the amount of coral bleaching, an early sign of 
stress, more than tripled. However, the study also found that once the injection of pollutants was stopped, the corals were able to recover in a surprisingly short time. ”We were shocked to see the rapid increase in disease and bleaching from a level of pollution that’s fairly common in areas affected by sewage discharge, or fertilizers from agricultural or urban use,” said Rebecca Vega-Thurber, an assistant professor in the College of Science at Oregon State University. “But what was even more surprising is that corals were able to make a strong recovery within 10 months after the nutrient enrichment was stopped,” Vega-Thurber said. “The problems disappeared. This provides real evidence that not only can nutrient overload cause coral problems, but programs to reduce or eliminate this pollution should help restore coral health. This is actually very good news.” However, unlike factors such as global warming or human population growth, nutrient loading is something that might be more easily addressed on at least a local basis, Vega-Thurber said. Improved sewage treatment or best-management practices to minimize fertilizer runoff from agricultural or urban use might offer practical approaches to mitigate some coral reef declines, she said. Read more here!… More:
The post Large Study Shows Pollution Impact on Coral Reefs, and Offers Solution appeared first on reefs.com.