Dec 2 2022Reviewed by Alex Smith
Various species hunker down as winter approaches for some much-needed rest, including bears, squirrels, and parasitic wasps. During this time, the northern star coral (Astrangia poculata) also enters a dormant state known as quiescence. However, what happens to its microbiome while it sleeps?
An active northern star coral under a microscope. When dormant, scientists found that its microbiome shifts while it sleeps. Image Credit: Alicia Schickle/Roger Williams University.
Research headed by Assistant Professor Anya Brown of the University of California, Davis discovered that microbial communities shift as this coral undergoes dormancy, presenting it with a critical seasonal reset. The findings could have ramifications for coral in warmer waters dealing with climate change and other environmental concerns.
Dormancy, at its most basic, is a response to an environmental stressor—in this case, cold stress. If we understand more about this recovery period, it might help us understand what microbes may be responsible for recovering coral in warmer tropical systems.
Anya Brown, Assistant Professor, Bodega Marine Laboratory, Department of Evolution and Ecology, University of California, Davis
The research, co-authored by experts from Woods Hole Oceanographic Institution and Roger Williams University and published in Applied and Environmental Microbiology, is the first to show a lasting microbial community shift with dormancy in a marine animal.
This study shows that microbes respond to stress and recover in a predictable pattern. It’s foundational knowledge that may help us develop probiotics or other microbial treatments for stressed tropical corals.
Amy Apprill, Study Co-Author and Associate Scientist, Woods Hole Oceanographic Institution
While the Corals were Sleeping
From October 2020 to March 2021, investigators plunged 60 feet into cold, nearly 40 °F water to harvest ten unique colonies of the coral A. poculata from a dock in Woods Hole, Massachusetts. This coral can be found in the Atlantic waters from the Gulf of Mexico to Massachusetts. When the temperature of the water drops, the coral pulls back its tentacles, stops eating and reacting to touch, and becomes dormant.
The researchers studied the microbiomes of wild corals before, during, and after dormancy. They discovered that while the coral “sleeps,” its microbiome loses nutrient-loving and pathogen-associated microorganisms while boosting microbes that may supply nitrogen. The researchers discovered that this reorganization aids corals in maintaining the structure of their microbial communities.
We have long hypothesized that Astrangia's seasonal dormancy allows the coral microbiome to reset and restructure. Our research found evidence for a shuffling during that dormant period that may help us identify microbial associates that are key to coral health and recovery from disturbance.
Koty Sharp, Study Co-Author and Associate Professor, Roger Williams University
Why Does Coral Wake Up?
With this research, the coral A. poculata enters bears, squirrels, crickets, and other animals on the list of animals discovered to have dormant microbiomes. The ground squirrel’s gut microbiota, for instance, is vital in nitrogen recycling while the squirrel fasts during hibernation.
Brown states, “This work opens a lot of questions. A big one is: Why does the coral ‘wake up’ in the early spring? This study suggests that key microbial groups may play an important role in triggering the onset of or emergence from this coral’s dormancy and the regulation of its microbiome.”
The research was financially supported by a WHOI Postdoctoral Scholar Award to Brown, as well as funding from the National Oceanic and Atmospheric Administration, National Science Foundation, and National Institutes of Health.
Journal Reference:
Brown, A. L., et al. (2022) Reshuffling of the Coral Microbiome during Dormancy. Applied and Environmental Microbiology. doi.org/10.1128/aem.01391-22.
Source: https://www.ucdavis.edu