The Great Barrier Reef is nowadays a world natural heritage site. However, it is really struggling against the greatest enemy of our time. That is, global warming. The increase in water temperature has in fact led to a decrease in the production of corals eggs. This, together with the events of mass bleaching, could lead to the decline of the ecosystem.
Such alarming situation has been revealed by a new Australian study on Nature. The Great Barrier Reef, off Australia’s northeastern coast, is the world’s largest coral system – as well as one of the planet’s most biodiverse ecosystems.
The coral reef was already a victim of global warming in 2016 and 2017. In those years, in fact, it suffered two mass bleaching events, which led to a huge loss of adult corals. As a result, researchers explain, the number of new coral larvae fell 89% from historical levels.
“Dead corals don’t make babies,” said Terry Hughes, on of the authors of the study. He is also director of the Arc Centre of Excellence for Coral Reef Studies, which is located at James Cook University in Queensland. The research measured the number of adult corals that survived extreme thermal stress and that of new corals produced to repopulate in 2018.
The data are even more alarming in the northern regions of the reef, i.e. those closest to the equator. Here, in fact, where the waters are even warmer, the number of new corals has fallen by 95%. The study found that the composition of the new corals has also changed. This will affect the recovery, making it slower than normal – as well as the ability to face future bleaching events.
Resilience has a vital role for the Great Barrier Reef. According to scientists, it depends on the number of coral larvae produced each year and where they travel before settling on a reef. Related to this, the study showed how global warming is strongly affecting the resilience of the reef. Researchers say that the extent to which the Great Barrier Reef will be able to recover remains uncertain. This is due to the expected increase in the frequency of extreme weather events over the next two decades.
The Great Barrier Reef has experienced mass bleaching events four times in the last 20 years, all attributed to global warming. Coral bleaching occurs when an increase in sea temperature or water acidification damages microscopic algae. This living organism is fundamental to corals, because it lives within them and provides them with energy – in addition to the characteristic vibrant and vibrant colors.
According to scientists, we must absolutely reduce current greenhouse gas emissions. Otherwise, the barrier will bleach twice every ten years starting from 2035 and every year after 2044.