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…
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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.