Researchers at FAU Harbor Branch Oceanographic Institute have unveiled groundbreaking findings that mesophotic corals could help restore Florida Keys’ shallow reefs, providing a beacon of hope for the region’s struggling coral ecosystems.
Research from Florida Atlantic University’s (FAU) Harbor Branch Oceanographic Institute offers new hope for the Florida Keys’ declining shallow reefs. The study, recently published in the journal Heredity reveals that mesophotic (deep-sea) coral ecosystems could play a crucial role in the recovery of shallow reefs within the Florida Keys National Marine Sanctuary (FKNMS).
Since the 1970s, coral cover in the FKNMS has plummeted, with up to a 50% reduction recorded between 1998 and 2011. The study focused on the blushing star coral (Stephanocoenia intersepta), a species found throughout the Western Atlantic that thrives in both shallow and mesophotic zones. Unlike their shallow-water counterparts, these deep-sea corals have largely escaped the catastrophic bleaching and stony coral tissue loss disease that have decimated shallow reefs.
By analyzing genomic DNA, the researchers examined the genetic diversity and connectivity of coral populations at various depths. Four distinct genetic lineages of blushing star coral were identified. Of particular interest were two depth-generalist lineages that exhibited strong genetic connectivity between shallow and mesophotic populations, suggesting that mesophotic reefs might serve as a vital genetic reservoir for the struggling shallow reefs.
“The blushing star coral has a wide range both in depth and geography, which makes it a great species for studying how populations at various depths and locations are linked,” first author Ryan Eckert, a doctoral candidate at FAU Harbor Branch, said in a news release. “Although blushing star corals are less common on shallow reefs throughout their geographic range, they become more abundant and cover more area in the mesophotic zone.”
These findings highlight the potential for deep-sea corals to aid in reef restoration efforts.
“Corals from deeper, mesophotic zones have a significant potential to help replenish and restore the declining shallow reefs in Florida Keys National Marine Sanctuary,” senior author and principal Joshua Voss, an associate research professor at FAU Harbor Branch, said in the news release. “Plus, important expansions planned in the ‘FKNMS Restoration Blueprint’ include additional protections for mesophotic corals throughout the Keys. ”
However, the study also noted the lower genetic diversity and higher inbreeding within shallow-specific coral lineages, potentially limiting their resilience and adaptability.
Yet scientists remain optimistic.
“[E]ven if these deeper corals can’t directly repopulate the shallow reefs with viable larvae in the future, they could still be valuable for creating a ‘seed bank’ or for rescue and breeding programs in land-based nurseries,” added Eckert.
This innovative research underscores the importance of protecting mesophotic coral environments as not just ecosystems in their own right but as vital contributors to the wider marine biodiversity and resilience of the Florida Keys’ coral reefs.
As Voss aptly put it, “By recognizing and characterizing the genetic biodiversity across different coral lineages, we can better manage and protect coral populations, especially as we face ongoing and future environmental challenges.”
The study’s promising results provide a beacon of hope for reef recovery and offer new tools and perspectives for coral conservation and restoration initiatives. As coral cover continues to decline, leveraging the genetic diversity and resilience found in mesophotic reefs could prove to be a pivotal strategy for preserving these vital underwater ecosystems.