Polluted groundwater presents a bigger risk to coral reefs in Hawaii than scientists previously thought, according to a new study by U.S. Geological Survey researchers.
“Local land-based pollution makes coral reefs more vulnerable to ocean acidification and could trigger coastal coral reef ecosystem collapses sooner than projected,” Lahaina News reported, citing the study.
“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,” the report said.
The study, published this month in The Journal of Geophysical Research, argues that pollution could “contribute to the collapse of coastal coral reef ecosystems sooner than current projections predict based only on ocean acidification.”
One of the key findings in the study is that water pollution is harming the environment more quickly than scientists expected.
“Bioerosion rates on corals next to seafloor groundwater vents off Kahekili Beach Park are up to eight times greater than expected for corals growing away from pollution,” Russell Sparks, a Maui-based aquatic biologist, argued in The Maui News, citing the study.
“The groundwater vent sites at Kahekili are composed primarily of wastewater effluent from the injection wells at the treatment plant. Water quality studies and dye tracer work have demonstrated that the groundwater discharging at Kahekili is contaminated by injected, treated wastewater with nitrate concentrations 50 times higher than background seawater concentrations. This fact has been conclusively shown and is currently undergoing legal litigation,” Sparks stated.
The U.S. National Ocean Service provides a useful graphic to demonstrate how land-based pollution threatens coral reefs. Threats include failed septic systems, stormwater runoff, and nutrients from farms.
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Image credit: "Sandy Beach Waves," Daniel Ramirez © 2011, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/