Are corals resistant to climate change?

Brut America

In New Caledonia, these scientists are testing the resilience of corals in the context of climate change, with the help of the Aquarium Des Lagons Nouvelle-Calédonie. And they might have found a way to repopulate reefs…

Transcript

00:00We are working on the impact of climate change on corals and more particularly on the acidification of the oceans

00:14to try to understand what the future will be.

00:30If we get to two more degrees and an acidification of the oceans less than 7.7,

00:45the EGEC predicts a loss of just 90% of coral reefs.

00:52It would seem that we have already lost 50% of the reefs on the Great Barrier Reef.

01:01All the CO2 emissions in the atmosphere are absorbed at 30% by the oceans

01:09and these emissions really impact the acidification because they will lower the pH.

01:14So what we are trying to do is to have different scenarios.

01:17The pH that will be predicted at the end of the century, we have the current pH,

01:21we also have the pH that is predicted in 30 years and in the end we did one last manipulation, it is a variable pH.

01:30We have species that come from a particular site that presents conditions that we will have at the end of the century

01:45and we would really like to try to understand why these corals manage to develop

01:49while other corals do not manage to develop in such extreme conditions.

02:00In this site near the mangroves, we have corals that resist extreme conditions in temperature, acidity and oxygen.

02:20Today the pH is 8.1.

02:23At the end of the century, we predict a pH of 7.7.

02:28Here in our site, we have a pH that reaches 7.4.

02:32It's huge, it's almost acid.

02:34We still have corals that resist.

02:37Our goal is to understand what mechanisms have been used to resist and still calcify.

02:50Calcification, what is it?

02:52It's really like bricks.

02:54It is the coral that will build the coral reef.

02:57This calcification is very important because not only does it serve as a shelter for all the species that are in it,

03:04but it can also serve as food.

03:06It serves a lot of things.

03:08It is really a very important ecological niche.

03:10What we are looking at is this possibility for corals to do a more or less varied calcification depending on the pH that they have.

03:28The effect of discovering corals that resist conditions in nature gives us hope.

03:45Of course, we are not naive.

03:47There are still particular conditions in this site.

03:51We will discover which ones.

03:53More and more, there is a trend called assisted evolution.

03:58To use this coral strain to repopulate the reef damaged by warming or other events in the future.

04:08Today, it's just hope.

04:10There is nothing concrete.

04:15It's a little naive to think that.

04:17Imagine, for example, the Great Barrier Reef in Australia is as long as Italy.

04:22Once we have lost this barrier, do you think that if we take, for example, a piece of coral like this

04:29and transplant it to several thousands, are we going to recover Italy?

04:35It's very hard to think.

04:43Today, we can't do it.

04:45In 20 years, maybe it will be better.

04:47Today, we are trying to find the resistant strains.

04:50Maybe in 20 years, we will use them to repopulate small areas of the Great Barrier Reef, etc.

04:57It's just hope.

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