In a new study, researchers have found that rescue efforts for critically endangered elkhorn coral species depend largely on the animal’s location, microbiome, and the right conditions to provide ample food.

Their findings showed that the unique oceanographic conditions in Florida’s Dry Tortugas National Park allow corals to thrive, positively affecting the coral microbiome (the thousands of different microbes that are naturally associated with it), improving both coral growth and survival. The study also shows that rescue efforts for the species will be most successful in areas that exhibit greater food availability, or areas rich in zooplankton, an important nutrient that helps build and repair coral tissue.

Over the past few decades, marine diseases, climate change, and a variety of other environmental factors have led to dramatic declines in populations of the deer coral (Acropora palmata), once an important reef ecosystem engineer in the Caribbean. Although small pieces of these corals are still found in the Caribbean, the species appears to be functionally extinct in Florida today, said Andrea Grottoli, the study’s senior author and professor of geosciences at Ohio State University. Although coral colonies remain, they are not sufficient to reproduce effectively.

“There are plenty of small pockets in other parts of the Caribbean, but in general elkhorn coral is a very sensitive species,” Grottoli said. Said. “It is no longer a core coral on Florida and Caribbean reefs, and this is a major loss to the ecosystem function of the reef.”

Healthy coral reefs in the Florida Keys help minimize coastal erosion and significantly contribute to the economic stability of the region through the federal fisheries administration and other tourism businesses, motivating government agencies and scientists to find the best strategies to save vital species.

Study published today in the journal Communication World and Environment explains how researchers are trying to do this by examining environmental variables that may contribute to the survival of the species. In 2018, researchers from the US Geological Survey (USGS) placed replicas of whitefish colonies at five different locations along Florida’s offshore coral reefs. Two years later, Grottoli’s team studied the physiology of corals to compare how the colonies lived.

Grottoli’s team measured a number of physiological characteristics important to coral survival, including biomass, oil content, and various coral nutritional markers. Grottoli said that overall, the health profiles of Elkhorn corals varied greatly between the five sites, but only coral samples at Dry Tortugas improved compared to all other sites, as some biological features indicated that Dry Tortugas corals were eating more zooplankton.

The favorable conditions in which these corals are found are likely associated with the region’s periodic uplift trend, an oceanographic phenomenon caused by wind that can bring nutrient-rich water to the surface from cooler, deeper waters. These events stimulate the production of zooplankton and bring an abundant food source to the area, making the area a true oasis for deer antler corals.

“These little extra bites of food can make a big difference to coral survival, and the data we measured are consistent with that interpretation,” Grottoli said. Said.

Grottoli said their research was hampered by travel restrictions and bad weather at the onset of COVID-19, but the results add to growing evidence that Dry Tortugas would be a logical place to try to restore Elkhorn coral. The study noted that recovering elkhorn coral in the Dry Tortugas could provide a new source of coral populations in the Florida Keys, but more research is needed to determine whether other at-risk coral species can thrive there. However, this will not solve all the problems faced by endangered coral populations.

“We’re trying to make smart decisions about conservation and restoration, but the gist of this study is that coral reefs are declining due to climate change and local stressors such as overfishing and pollution,” Grottoli said. Said. “No matter how smart we are about restoring and conserving corals, we always put a Band-Aid on it until we address these two issues.” Source