According to a study published in the journal Nature Communications , the Great Barrier Reef off the eastern coast of Australia underwent remarkable temperature changes between 20,000 and 13,000 years ago, to which it was able to adapt. The longest and most extensive reef in the world, at 2,000 km in length, is a unique ecosystem that has evolved over thousands of years and has been a UNESCO World Heritage Site since 1981 . Due to its apparent fragility, scientists fear that global warming could cause irreversible deterioration, however this research led by the Marine Research Institute (MARUM) of the German University of Bremen (Germany) seems to indicate that the Gan Barrier may be more resistant to changes in sea surface temperature than previously thought.
The study is based on samples collected by an expedition of the Ocean Discovery International Program (IODP), aimed at analyzing the processes of adaptation to thermal changes in these animal ecosystems at the end of the last ice age, 20,000 to 13,000 years ago. , when there was a significant rise in temperatures. The experts studied the fossils of Isopora corals, which lived at the end of the last glacial period and which continue to inhabit and develop today in the shallow waters of the Great Barrier Reef. Using radiometric dating techniques of uranium-thorium, they have been able to identify coral fossils that lived in the central and final stages of the aforementioned glacial period, and have confirmed that it is a very flexible ecosystem. They also measured the strontium-calcium ratios in the corals to determine the ocean temperatures at that time . The results show that sea surface temperatures off the eastern coast of Australia between 20,000 and 13,000 years ago were noticeably colder than previously thought, and that the north-south thermal oscillation was unsuspectedly wide: “In At that time, the water in the south was two to three degrees cooler than in the north, while currently the difference does not reach one degree, “according to the study. Although research shows that Isopora corals have endured very large temperature fluctuations in the past, it is still unknown how they were able to adapt in a few thousand years and why this did not affect their growth.
Despite this, scientists warn that it cannot be deduced from this that the Barrier Reef as it is today can easily adapt to a continuous increase in temperatures. Along with warming, the main threats to the survival of coral reefs today are ocean acidification and increased entry of sediment by human activities on the coast.
