News — Researchers have found a novel way to identify heat-stressed corals, which could help scientists pinpoint the coral species that need protection from warming ocean waters linked to climate change, according to a Rutgers-led study.

“This is similar to a blood test to assess human health,” said senior author , a Distinguished Professor in the  in the  at . “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, nursery and spawning grounds for fish, food for about 500 million people along with their livelihoods, and coastline protection from storms and erosion. But global climate change threatens corals by warming ocean waters, resulting in coral bleaching and disease. Other threats to corals include sea-level rise, a more acidic ocean, unsustainable fishing, damage from vessels, invasive species, marine debris and tropical cyclones, according to the .

The study, , examined how Hawaiian stony corals respond to heat stress, with a goal of identifying chemical (metabolite) indicators of stress. Heat stress can lead to the loss of algae that live in symbiosis with corals, resulting in a white appearance (bleaching) and, potentially, the loss of reefs.  

Scientists subjected the heat-resistant Montipora capitata and heat-sensitive Pocillopora acuta coral species to several weeks of warm seawater in tanks at the Hawaiʻi Institute of Marine Biology. Then they analyzed the metabolites 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,” Bhattacharya said.

The scientists are validating their coral diagnosis results in a much larger study and the results look promising. The scientists are also developing a “” featuring a new lab-on-a-chip device, which could check coral health in the field via metabolite and protein indicators.

The coral hospital work is in collaboration with  Professor  and , an assistant professor at and director of the at the . Rutgers co-lead authors for the Hawaii study include doctoral student  and Eric N. Chiles, research teaching specialist at . Other Rutgers co-authors include Jananan S. Pathmanathan, a post-doctoral associate, and Professor Su. Researchers at the University of Rhode Island and Stanford University contributed to the study.

Journal Link: Science Advances