Tuesday, June 13, 2017



‘Super Corals’ Are Resilient To Climate Change, Scientists Discover

Scientists have discovered a population of “super corals” that appear to have become resistant to extreme environmental conditions — being able to survive and thrive in hot, acidic and low-oxygen waters. And they now plan to search for more climate-adaptable coral populations within the Great Barrier Reef.

An international team of researchers first found the super corals during an expedition to a remote lagoon in New Caledonia in 2016. Their “surprising results” showed the lagoon had a diverse community of reef-building corals that had adapted to live in extreme these conditions.

Publishing their findings in the journal Scientific Reports, the team was investigating coral reef health in relating to climate change. As oceans get warmer and more acidic, vast swathes of coral species suffer. This has been documented globally, with a recent report from the Australian Research Council showing two thirds of the Great Barrier Reef had been affected so far this year.

Coral bleaching occurs when waters are too warm. These conditions make the corals expel the algae living in their tissues—causing them to lose their color. Algae provides coral with 90 percent of its energy, so while this process does not kill it, it places the coral under far greater stress and puts it at greater risk of death.

As global temperatures increase, scientists are increasingly concerned about how coral reefs—which form barriers protecting shorelines from waves and storms, and provide ecosystems for a vast number of species—will fare.

The latest findings provide some relief. Emma Camp, from the University of Technology Sydney (UTS), Australia, and colleagues found water in the semi-enclosed lagoon system was hot, acidic and lacking in oxygen when compared to neighboring reefs. Yet its coral communities was surprisingly rich—there were 20 species covering up to 35 percent of the lagoon site.

“Enhanced coral respiration, alongside high particulate organic content of the lagoon sediment, suggests acclimatisation to this trio of temperature, oxygen and pH changes through heterotrophic plasticity.” Heterotrophic refers to organisms that depend on organic substances for nutrients because they cannot make their own food.

In a statement, Camp said: “The existence of corals living under this usually deadly trio of conditions, comparable and even exceeding what is predicted under climate change, gives us new hope that some corals will be able to persist into the future. These could indeed be the super corals of the future that will help support proactive management options attempting to upgrade reef resilience.”

Concluding, the team wrote: “Evidence here, and from other similar habitats increasingly highlight that reef neighboring systems could act as local reservoirs of coral populations highly resistant to extreme environmental conditions.”

The next step in their research is to search for similar systems in the Great Barrier Reef. The expedition, funded by the National Geographic Society Waitt Foundation, will allow the team to explore mangrove systems—which have similar, extreme conditions to those seen in New Caledonia—and how corals there may have adapted.

“As a result of the expedition we will be able to collect invaluable baseline physical and molecular data to discover how corals within the Great Barrier Reef have already adapted and how they might cope in the future,” Camp said. “I’m excited at the prospect of being able to transfer our discoveries from other sites to our own home reefs.”

David Suggett, who will accompany Camp on the expedition, said: “By exploring the very margins—such as reef-neighbouring mangroves that are often ignored by coral surveys—we’re continually finding populations of super coral that are resistant to hot, acidic and hypoxic conditions predicted under climate change. This is a game changer for how we consider coral reef resilience into the future for the Great Barrier Reef.

SOURCE