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USVI - Fire Coral Winning the Battle for Domination of Caribbean Reef, CSUN Prof Says

Every year for the past 30 years, California State University, Northridge marine biologist Peter Edmunds has traveled to the Caribbean island of St. John in the U.S. Virgin Islands to document the life history of fire coral on nearby reefs.

In recent years, he has had grants to pay for the research, but he tapped into his savings to cover the expenses at the start of his project. When the COVID-19 pandemic hit, he worked closely with university officials to establish safety protocols to ensure his efforts to chronicle the life of the St. John fire coral continued.

“This is more than just a story about fire coral because in that environment, space is a limited resource,” Edmunds said. “If you’ve got it, you’re doing well. If you don’t have it, you want to get it and have to fight for it.     Imagine a wall is your marine environment and stuff is duking it out on the top to gain that space. The species that holds the space becomes the winner. One of the ways that organisms do that is through the strategy of shape. What shape do they have? How do they use that shape to exploit that space?”

In the battle over the limited space on the shallow reefs of St. John, Edmunds has declared fire corals — with their ability grow either as sheets or trees — the winner.

“They have a strategy that allows them to spread when they can, allows them to produce  branches when they can, and how they exploit that determines their fitness,” he said. “Fire coral have been around for millions of years and what they are doing is pretty darn successful. I would posit that having gone this far, they are actually now poised to be somewhat the inheritors of the reef, while other corals, particularly stony corals, die back.”

His findings, “Persistence of a sessile benthic organism promoted by a morphological strategy combining sheets and trees,” appear this month in the prestigious Proceedings of the Royal Society B, one of the world’s leading biological research peer-reviewed journals.

Edmunds’ work builds on a seminal 1979 paper published by respected ecologist Jeremy Jackson, emeritus professor at the Scripps Institutions of Oceanography, senior scientist emeritus at the Smithsonian Institution and visiting scientist at the American Museum of Natural History Center for Biodiversity and Conservation. In the 1979 paper, Jackson argued that an animal’s shape is important to determining its survival rate in a marine environment.

“I was able to take the data I have collected for every year for the past 30 years for an organism that has this unusual strategy of using its shape, and I was able to place it in this theory articulated by Jeremy Jackson — it’s super cool,” Edmunds said, adding that his research leaves questions about how the fire coral knows when to spread out their sheet form to take over space left by a dying sponge or when it’s a good time to grow upward in their tree form.

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