New tool can detect heat stress in corals

A new method of identifying heat-stressed corals could help scientists pinpoint the species that need protection from rising ocean temperatures. Experts led by Rutgers University have developed a tool that can detect a coral’s response to heat stress based on chemicals produced for metabolism.

“This is similar to a blood test to assess human health,” said study senior author Professor Debashish Bhattacharya. “We can assess coral health by measuring the metabolites (chemicals created for metabolism) they produce and, ultimately, identify the best interventions to ensure reef health.” 

“Coral bleaching from warming waters is an ongoing worldwide ecological disaster. Therefore, we need to develop sensitive diagnostic indicators that can be used to monitor reef health before the visible onset of bleaching to allow time for preemptive conservation efforts.”

Coral reefs provide habitat for an estimated 25 percent of all marine life, including over 4,000 species of fish, while supporting the livelihoods of about 500 million people. Warming ocean temperatures, sea-level rise, ocean acidification, unsustainable fishing, and invasive species are all major threats to the future survival of corals.

Heat stress can lead to the loss of algae that live in symbiosis with corals, which results in bleaching that can be deadly. The Rutgers team set out to identify the chemical indicators of stress by examining how Hawaiian stony corals respond to heat. 

The scientists exposed the heat-resistant Montipora capitata and heat-sensitive Pocillopora acuta coral species to several weeks of warm seawater in tanks at the Hawaii Institute of Marine Biology. Next, they investigated the metabolites that were produced and compared them with other corals not subjected to heat stress.

“Our work, for the first time, identified a variety of novel and known metabolites that may be used as diagnostic indicators for heat stress in wild coral before or in the early stages of bleaching,” said Professor Bhattacharya.

Currently, the researchers are validating their coral diagnosis results in a much larger study. They are also developing a “coral hospital” that could check coral health in the field through metabolite and protein indicators.

The study is published in the journal Science Advances.

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By Chrissy Sexton, Earth.com Staff Writer