In 2015, nearly half of Hawaii’s coral reefs were affected by the worst bleaching event to date. Coral bleaching occurs when warmer ocean temperatures encourage corals to excrete algae that normally live within and where corals rely on food.
The bleaching incident was horrifying. But sometimes corals can recover. while some events are totally anti-bleaching. In a new study in the journal Proceedings of the National Academy of Sciences, Researchers led by Katie Barott from the University of Pennsylvania It was found that battle-tested, resilient corals were able to grow. Even if transplanted in different environments and subjected to additional heat stress. The findings provide hope that healthy corals can serve as precursors to future reef restoration.
“The big thing that we’re really interested in here is trying to do that experiment. Are you using corals that seem to be resistant to climate change? and used as seeds for propagation and release on other reefs that may deteriorate,” Barott said. “The great thing is that we didn’t see any difference in the response to bleaching after planting. Take this time”
Coral bleaching events are becoming more frequent. This has raised concerns that corals will become victims of climate change in the near future, but Barott and colleagues have studied corals that resist bleaching. It aims to buy corals to give them more time to cope with warming and acidic seas.
One strategy they and others have come up with and have tried in areas such as the Great Barrier Reef is coral transplantation. Researchers can replenish coral reefs damaged by climate change or other human insults, such as sedimentation or boat bottoms. With coral proven to be tough and able to survive the tough conditions.
However, for this to work, the “survivor” coral must continue to exhibit resilient attributes after being moved to a new environment.
“If you bring bleach-resistant coral in its habitat, The stress of moving to a new place can cause them to lose that ability,” Barott said.
Like a fern that grows well in the shade, it can wither if moved to a sunny plot. the state of the new environment This includes the water flow rate. access to available food, light and nutrients It can affect the resilience of cultivated corals.
Barott and colleagues worked on this question with two reef experiments in Hawaii’s Kaneohe Bay on Oahu Island. One is closer to the coast and has more calm waters. and another one away from the coast with higher tides. in each area Researchers identified coral groups that resisted bleaching during the 2015 bleaching event and collected samples from them the following year. Corals are cloned organisms. Therefore, fragments taken from colonies can regenerate and will be genetically identical to the “mother” coral for each colony. They collected some samples on the native reef and moved others to the second reef.
After the coral spent six months in the new location. Biologists also took coral samples from each site in the lab tanks. and simulated another bleaching event by raising the water temperature over several days.
Careful monitoring of the health of corals and their surrounding environment The team measured rates of photosynthesis, metabolism and calcification rates. as well as the health of biological algae They found that bleach-resistant corals remained so. even in a new environment
Barott said, “Something really strange. is that we have this highly simulated experiment. And we didn’t see any change. in response to coral bleaching.”
The researchers also studied how well corals reproduce in the summer they collect. Corals’ natural site conditions affect their future reproductive performance.
Barott said that “corals from the “happy” region, the outer lagoon, showed higher growth rates than before the bleaching. They generally look a little happier and their performance is higher. “That tells us that If you are going to have a coral nursery You should choose a site that is in good condition. Because it seems useful to spend time on a better site. Although fewer corals have been planted ‘Happy Site’
A “happy” area far from the lagoon side. Has a higher flow rate than other coral reefs. which is closer to the shore It is less salty and more stable. “Higher flow rates are very important to help corals get rid of waste and get food,” Barott said.
Barott, who began working as a postdoc at the Hawaii Institute of Marine Biology, continues research on coral resilience in her lab at Penn, including investigating the effects of heat stress and bleaching on success in coral reefs. Reproduction and function of coral sperm
Although the results of transplant studies are promising But she said it would only be a temporary solution to the threat of climate change.
“I think a technique like this can buy us a little bit of time. But there is no substitute for limiting carbon emissions,” she said. “We need global action on climate change because even bleach-tolerant corals cannot survive forever if global warming occurs. The heat continues to rise as fast as today.”
Models show that corals are more resistant to global warming. If changing to more heat-resistant algae more
Katie L. Barott et al, Coral bleaching reaction does not change after acclimatization of coral reefs with different environmental conditions. Proceedings of the National Academy of Sciences (2021). doi: 10.1073/pnas.2025435118
Provided by the University of Pennsylvania
reference: Climate change resistant corals can provide a lifeline to battered reefs (2021, 28 May). Retrieved 29 May 2021 from https://phys.org. /news/2021-05-climate-change-resistant-corals-lifeline-battered.html
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