In a recent study published in ISME Communications, a team of researchers led by the Woods Hole Oceanographic Institution (WHOI) examined the health effects of reef microorganisms from chemical compounds released by coral species. This study has the potential to help us better understand the evolution of coral dominance, specifically in the Caribbean, as these corals continue to shift from hard stony corals to soft octocorals due to human-caused effects, to include overfishing, eutrophication, and global climate change.
"We wanted to know what are the molecules that coral organisms release into the environment, and how do those molecules impact the reef microbes in the seawater surrounding the corals," said Dr. Laura Weber, who is an information systems associate in WHOI's Marine Chemistry & Geochemistry Department, and lead author of the study. "As the species composition of these reefs shifts, it is likely changing the chemicals that are released on the reef that then will have impacts on the microbial community. We need to pay more attention to how changes in reef structure and species composition might influence the microbes that live on the reef, leading to more feedbacks in terms of reef health."
The research team carried out their study by collecting samples from the Virgin Islands National Park, along with six species of Caribbean benthic organisms in a lab setting. The collected organisms included octocorals, stony corals, and an invasive alga known as Ramicrusta textilis. Along with determining the health effects of reef microbes, the researchers were surprised to discover that R. textilis discharged high quantities of caffeine into the environment, as well.
While the study notes that while caffeine production is often produced by land plants as a deterrence for pathogenic microbes and herbivores, this has not been widely investigated for marine life. The characteristics of caffeine production "could contribute to the ability of R. textilis to invade and flourish on Caribbean reefs," according to the study, which goes on to state, “"Given the growing prevalence of Ramicrusta on diverse Caribbean reefs, follow-up research examining the ecological significance of its metabolites on microbes and other reef organisms is needed."
The research "is an important step forward in identifying chemical signals that can help scientists assess reef health," said Dr. Elizabeth Kujawinski, who is a senior scientist at WHOI, and a co-author on the study. "Similar to human health diagnostics, the chemical signals within a reef ecosystem are intimately linked to the functions of the symbiotic relationships within reefs."
Sources: ISME Communications
As always, keep doing science & keep looking up!