Uncovering Secrets to Coral Survival in a Changing Climate

Reef-building lace coral provide habitats for many species of fish. ©Shedd Aquarium/Ross Cunning
Reef-building lace coral provide habitats for many species of fish. ©Shedd Aquarium/Ross Cunning

By Grace Klinger, Science Communication Fellow at Shedd Aquarium

Corals are diverse organisms that provide food and homes to millions of marine species, promoting biodiversity in our oceans. Some are soft, some are stony. Some live in deep water, some in shallow. Some build reefs, some stand alone. And while all share a preference for saltwater, most stay in their own oceans, making Atlantic corals far different from those in the Pacific, etc. To date, there are hundreds of coral species that build reefs, all which vary in texture, shape and where they choose to live.

Because of these differences, they also behave and respond to changing environments differently.

Coral reefs have been declining rapidly due to environmental changes such as ocean acidification that inhibits coral growth (biomineralization), ocean warming that disrupts coral’s interactions with the photosynthetic algae that supplies it with both its beautiful color and energy (symbiosis), and outbreaks of coral diseases (immune response). Understanding corals’ different responses to these environmental stressors can help in conservation efforts to stop coral decline.

One of the first steps toward understanding starts with genome sequencing.

A genome is like blueprints of a living organism. When a genome is “sequenced,” we can read those blueprints and learn how an organism functions. When it comes to the “blueprint” of coral, for example, genome sequencing allows us to understand their evolution and how they have survived past and present global climate change.

So, to help answer questions about coral responses to a changing climate, scientists sequenced the genome of one of the most widely distributed and studied coral species in the world, lace coral (Pocillopora damicornis).

Understanding Lace Coral

Lace coral is a reef-building coral, important for laying the bed-work of many coral reefs across the Pacific Ocean and into the Indian Ocean. Not only is it important ecologically, but it also serves as a model for many areas of coral scientific research from reproduction and genetics to evolutionary biology. By sequencing all of the lace coral’s “blue prints” or genes, we get a better picture of how it has adapted over time to become one of the most widespread coral species, and how it may adapt to future stressors.

Close-up of Lace Coral
Lace coral (Pocillopora damicornis) photographed from a research trip in Panama. ©Shedd Aquarium/Ross Cunning

Hidden within the lace coral’s genome, researchers from the University of Miami Rosenstiel School of Marine and Atmospheric Science – including Shedd Aquarium’s coral research biologist, Dr. Ross Cunning – found many unique immune functions that may allow it to cope with diseases and changes in its environment.

The genome of lace coral, published in Nature: Scientific Reports, was compared to other marine invertebrates, including sponges, anemones, and other reef-building corals. Their goal was to find important genes specific to the reef building coral or any genes that distinguish lace coral from others that could explain its evolutionary success.

The research team found genes shared between reef-building corals that take care of normal functions, called “housekeeping” genes. These housekeeping genes made up nearly half of the lace coral’s genome. In addition, lace coral exhibited many genes related to immune function that were not shared with other coral. Perhaps these genes facilitate the unique strategies that enable lace coral to adapt to stressors and help explain its wide range.

This discovery gives scientists hope that lace coral, and possibly others, may be able to adapt to environmental stressors such as pathogens in the oceans or climate change.

Now that there is a reference genome, it lays the foundation for many other questions we can ask about corals that could help our understanding of how corals have survived and if they will continue to survive in a changing ocean environment.

You Can Help Corals Too

Outside of mapping the genomes of corals and understanding what makes them resilient, everyone can help contribute to the conservation of coral reefs. You can learn about climate change and its global impacts and reduce your carbon footprint by carpooling or taking public transportation or one of the many suggestions outlined by the International Society for Reef Studies.

To learn more about ways you can protect corals, visit the National Oceanic and Atmospheric Administration website.

Changing Planet

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Meet the Author
The John G. Shedd Aquarium in Chicago sparks compassion, curiosity and conservation for the aquatic animal world. Home to 32,000 aquatic animals representing 1,500 species of fishes, reptiles, amphibians, invertebrates, birds and mammals from waters around the globe, Shedd is a recognized leader in animal care, conservation education and research. An accredited member of the Association of Zoos & Aquariums (AZA) and the first U.S. aquarium to be awarded the Humane Conservation™ certification mark for the care and welfare of its animals by American Humane, the organization is an affiliate of the Smithsonian Institute, and is supported by the people of Chicago, the State of Illinois and the Chicago Park District. www.sheddaquarium.org