Image of the Day: Eroded Coral

Coral reefs near Maui, Hawaii, show signs of erosion due to excess nutrients from wastewater.

Apr 11, 2019
Chia-Yi Hou
ABOVE: Coral that has eroded heavily was found near a groundwater discharge point off the coast of Maui, Hawaii.
NANCY PROUTY, USGS

Researchers published a study showing the effect of nearby wastewater treatment plants on reefs off the coast of Maui, Hawaii, in Scientific Reports on April 3. They sampled the nitrogen in each of the layers of coral dating back to before 1995.

“It’s a very accurate and high-resolution way to record past nutrient pollution in seawater, which is a huge problem globally,” says coauthor Adina Paytan of University of California, Santa Cruz, in a press release.

Her study shows reef erosion can be traced back to wastewater treatment plants based on nitrogen isotope signatures found in the reefs and sewage water.

J. Murray et al., “Coral skeleton δ15N as a tracer of historic nutrient loading to a coral reef in Maui, Hawaii,” Scientific Reports, doi:10.1038/s41598-019-42013-3, 2019.