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Coral parents pass algae to their offspring to help cope with climate change

By
Brooks Hays
Some corals can pass along algal communities to their offspring to help them cope with rising ocean temperatures. File Photo by Wagsy/Shutterstock
Some corals can pass along algal communities to their offspring to help them cope with rising ocean temperatures. File Photo by Wagsy/Shutterstock

Sept. 16 (UPI) -- If coral are to survive global warming, they're going to need some help from their parents. New research suggests coral parents can instill resilience in their offspring, not by passing along the right genes, but by providing the right kinds of algae.

Climate change has warmed the world's oceans over the last several decades. Nearly half of all coral reefs have experienced severe coral bleaching as a result. When coral becomes stressed by heat, they expel the algae they rely on for food.

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But some coral are more resilient than others, and scientists around the world have been working hard to better understand how some coral manage to withstand variable conditions.

New research out of the University of Southern California suggests some coral inherit the ability to rearrange their community of symbionts, the algae colonies inside their cells.

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"What we're finding is that corals can pass their shuffled complement of algal partners, or symbionts, to their offspring to bestow a potential survival advantage, and that's a new discovery," Carly Kenkel, an assistant professor of biology at the USC, said in a news release. "We care about this because coral reefs do so much for us. A reef provides breakwater for storms, fish protein people need and biodiversity we love and find beautiful."

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The algae that partner with coral are dinoflagellates, a group of phytoplankton. The algae get shelter from coral, while the coral usurp some of the energy algae harvests from sunlight via photosynthesis. The coral use some of that energy to synthesize calcium carbonate to build out the skeleton architecture that forms coral reefs.

The relationship is relatively harmonious when times are good, but as happens among many species, stress often triggers breakups.

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While some corals kick all their algal partners out, more resilient corals simply reshuffle the lineup of symbionts.

For the latest study, scientists analyzed the DNA of algae communities in coral parents and offspring during spawning events. The research showed more resilient corals featured shifting numbers and kinds of algae living inside their cells from year to year compared to those that suffered most during coral bleaching events.

Researchers determined the algae species Montipora digitata can pass along shuffled algae communities in their eggs when they reproduce, and that those algal communities can be adopted by their offspring.

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Kenkel and her colleagues reported their findings Monday in the journal Scientific Reports.

More and more studies are revealing coral's ability to adapt, but it's not clear if their innate resiliency will be enough to withstand the effects of climate change. Scientists hope additional research will reveal ways conservationists can enhance the resiliency of coral communities.

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"Corals have more mechanisms than we thought to deal with climate change, but they're fighting with a tiny sword against a foe that's like a tank," Kenkel said. "Their adaptability may not be enough. They need time so they can adapt."

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