New technique could help scientists identify heat-stressed corals

Jan. 4 (UPI) -- Scientists have developed a new technique for identifying heat-stressed corals, information that could help marine biologists diagnose the coral species most vulnerable to global warming.

The research, published this month in the journal Science Advances, promises to help conservationists craft more targeted marine protections.

"This is similar to a blood test to assess human health," senior author Debashish Bhattacharya said in a news release.

"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," said Bhattacharya, a professor of biochemistry and microbiology at Rutgers University.

"Coral bleaching from warming waters is an ongoing worldwide ecological disaster," Bhattacharya said. "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 anchor the food chains and ecosystems that support much of the ocean's biodiversity. They're vital to many of the world's most important fish stocks.

Additionally, coral reefs protect approximately 44,000 miles of coastline from flooding and storm surges, saving coastal communities billions of dollars every year.

Unfortunately, many of the world's reefs face a variety of growing threats, including rising ocean temperatures, ocean acidification, harmful invasive species, pollution and overfishing.

For the new study, researchers exposed Hawaiian stony corals to heat stress and recorded the metabolic, or chemical, signatures of stress.

Coral get their color from the algae that reside in their skeletal cavities. The algae form a mutualistic relationship with coral, providing nutrients in exchange for protection.

But when water temperatures get too hot, the algae abandon their coral homes and flee -- leaving coral vulnerable and without their color. The phenomenon is known as coral bleaching.

The recent lab experiments, which involved both heat-resistant and heat-sensitive coral species, showed corals begin to produce unique metabolites in response to heat stress.

The metabolic signatures could help marine biologists identify vulnerable coral weeks before the reefs begin to exhibit signs of bleaching.

"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 research team is currently working on the development of a lab-on-a-chip "coral hospital" that could monitor coral metabolites in real-time.