Study finds pollution on land damages coral reefs

Local land-based pollution makes coral reefs more vulnerable to ocean acidification and could trigger coastal coral reef ecosystem collapses sooner than projected, according to new research.

Coral reefs are threatened globally by ocean acidification caused by rising levels of atmospheric carbon dioxide. The carbon dioxide influx heightens the ocean’s acidity, creating an environment that stunts coral growth. A new study, accepted for publication in the Journal of Geophysical Research: Oceans, a journal of the American Geophysical Union, finds local land-based pollution can make coral reefs even more vulnerable to ocean acidification by magnifying its effects.

The new study finds pollution from a wastewater treatment facility in west Maui, Hawaii, has drastically weakened local coral reefs for more than 10 years. By increasing local seawater acidity and nutrient levels, the polluted water has instigated harmful bioerosion and inhibited coral reef growth.

The researchers found seawater closer to the groundwater-leaking seeps had a lower pH, less carbonate available, and nitrate levels 50 times higher than seawater farther from the seep site. Accordingly, the corals closer to the seeps grew slower and exhibited more bioerosion compared to corals situated farther from the seep sites. These corals were noticeably pitted and riddled with holes, a sign that algae-hungry creatures had excavated into the coral skeleton.

Read more on AGU’s GeoSpace blog

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