Remote Indian Ocean reefs bounce back quickly after bleaching
Date:
March 24, 2022
Source:
University of Exeter
Summary:
Coral reefs in remote or protected areas can recover quickly after
mass coral bleaching events, new research shows.
FULL STORY ========================================================================== Coral reefs in remote or protected areas can recover quickly after mass
coral bleaching events, new research shows.
========================================================================== University of Exeter researchers are investigating "reef carbonate
budgets" - - the net production or erosion of reef structure over time.
To study the impacts of climate change on reef functions, they examined
12 reefs in the remote Chagos Islands in the Indian Ocean before and
after the global coral bleaching event in 2015/16.
In 2018, the formerly thriving reefs were "shrinking," with coral cover
and carbonate production down by more than 70% and erosion processes
exceeding new coral growth.
When the researchers returned in 2021, all reefs were on a trajectory
of recovery, although the speed varied from place to place.
Where key coral species returned quickly and the underlying physical
reef structure had stayed intact, reefs showed a rapid transition back
to positive growth only six years after the bleaching event.
========================================================================== Bleaching is caused by warmer water temperatures, which can trigger corals
to expel their symbiotic algae and turn white. Corals can survive this,
but an extreme heat wave causes large-scale mortality.
The speed of subsequent recovery is an important indicator of a reef's
health and resilience.
"Such high rates of coral recruitment and the rapid restoration of reef functions are a very nice surprise and imply that this location is showing
some resilience, thus far, to ongoing ocean warming," said lead author
Dr Ines Lange, a postdoctoral research fellow in a multi-institutional
project funded by the Bertarelli Program in Marine Science.
"A full recovery of reefs across the Chagos Archipelago over the next
few years is likely if the region is spared from reoccurring marine
heating events." Dr Lange added: "The study shows that in remote and
protected areas without local impacts such as fishing or pollution from
land, coral reefs and the important functions they provide are able to
recover relatively quickly, even after large-scale disturbances.
"Proximity to healthy coral populations and the maintenance of a complex
reef structure seems to boost recovery speed, which may help to manage
reefs under the threat of increasing frequency of bleaching events
predicted for the near future." Co-author Professor Chris Perry, from
the University of Exeter, developed the census-based ReefBudget method
to quantify reef carbonate budgets.
These carbonate budgets are important indicators of a reef's ability to
provide habitat to marine life, protect shorelines from wave energy and
help reef islands to keep up with future sea level rise.
Over the last years, Prof Perry and Dr Lange optimised the method for
the central Indian Ocean by quantifying and integrating local rates of
coral growth and parrotfish erosion.
========================================================================== Story Source: Materials provided by University_of_Exeter. Note: Content
may be edited for style and length.
========================================================================== Journal Reference:
1. Ines Lange, Chris Perry and Marleen Stuhr. Recovery trends of reef
carbonate budgets at remote coral atolls six years post-bleaching.
Limnology and Oceanography, 2022 [abstract] ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220324104405.htm
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