In a new study, researchers found that efforts to restore elkhorn species depend on the animal’s location, microbiome, and the right conditions to provide plenty of food.
Their findings show that the unique ocean conditions in Florida’s Dry Tortugas National Park provide corals with the opportunity to thrive, enhancing coral growth and survival while positively influencing the coral microbiome. -the thousands of different microbes that naturally associate with them. Research also shows that restoration efforts for species may be most successful in areas that exhibit high food availability, or areas that are abundant in zooplankton, a key source of nutrition that helps build and coral tissue repair.
Over the past several decades, marine disease, climate change and other environmental stressors have caused populations of elkhorn coral (Acropora palmata)—once a major engineer in the reef ecosystem of the Caribbean—which will experience a significant decline. Although small patches of these corals can still be found in the Caribbean, now the species appears to be extinct in Florida, said Andréa Grottoli, senior author of the study and a professor of Earth sciences at The Ohio State University. While there are coral colonies left, there aren’t enough of them to reproduce effectively.
“In other parts of the Caribbean, there are small pockets where there is enough of it, but overall, the elkhorn coral is a very sensitive species,” Grottoli said. “It’s no longer the primary coral on Florida and Caribbean reefs, and that’s a huge loss to that reef ecosystem function.”
In the Florida Keys, healthy coral reefs help reduce coastal erosion and contribute significantly to the region’s economic stability through federally managed fisheries and other tourism-based businesses, which provide a boost of government agencies and scientists to find the best strategies for the restoration of important species.
The study, published today in the journal Earth and Environment Communication, describes how researchers aim to do this by studying environmental changes that may contribute to species survival. In 2018, United States Geological Survey (USGS) researchers placed replica elkhorn colonies at five different locations along Florida’s coral reef coast. After two years, Grottoli’s team sampled the coral’s physiology to compare the conditions of the colonies.
Grottoli’s team measured a number of physiological traits important to coral survival, including biomass, fat content and various markers for coral feeding.
Overall, elkhorn coral health profiles differed significantly among the five sites, but only the coral samples at the Dry Tortugas improved compared to all other sites, Grottoli said, because some biological characteristics show that Dry Tortugas corals eat a lot of zooplankton. .
The favorable conditions experienced by these corals are likely due to the site’s propensity for periodic upwelling, a wind-driven oceanographic phenomenon that brings upwellings of nutrient-rich water to the surface from cooler, more deep waters. These events stimulate the production of zooplankton and bring a large amount of food source to the region, making the area a true oasis for elkhorn coral.
“These small pulses of extra food can make a big difference in coral survival and the things we measured are consistent with that interpretation,” Grottoli said.
Grottoli said their research was challenged by early COVID-19 travel restrictions and bad weather, but the results add to a growing body of evidence that the Dry Tortugas is a logical place to try to bring back the elkhorn coral. The study says that restoring elkhorn corals in the Dry Tortugas could also provide a population source for new coral recruits throughout the Florida Keys, but more research is needed to determine if the other endangered coral species can also thrive there, Grottoli said. However, this does not solve all the issues facing endangered coral populations.
“We are trying to make smart conservation and restoration decisions, but at the core of this work is that coral reefs are declining due to climate change and local stressors such as overfishing and pollution,” said Grottoli. “Until we address those two things, no matter how smart we are about restoring and preserving coral, we’re always putting a band-aid on it.”
Leila Chapron et al, Heterotrophy, microbiome, and location effects on restoration effectiveness of the threatened coral Acropora palmata, Earth and Environment Communication (2023). DOI: 10.1038/s43247-023-00888-1
Provided by The Ohio State University
Citation: In Florida, endangered coral finds way to bloom (2023, July 17) retrieved on July 17, 2023 from https://phys.org/news/2023-07-florida-endangered-coral-blossom.html
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