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Geologists have found that ocean warming may have contributed to the formation of the Great Barrier Reef hundreds of thousands of years ago.
New research by geologists from Germany, Austria and Great Britain shows that ocean warming in the past contributed to the formation of the Great Barrier Reef, the largest reef ecosystem in the world. Using paleoclimate data, scientists reconstructed the history of changes in ocean surface temperature over the past 900 years and found that periods of warming created favorable conditions for coral growth.
Results published in journal Science Advances, showed that the surface temperature of the Coral Sea during key stages of reef development fluctuated between 26 °C and 30 °C. For example, between 712 and 524 years ago, temperatures were similar to today's, and long periods of warmth with high and stable sea levels coincided with active growth of the reef system.
"Our data show that two degrees of warming may have been a critical factor that allowed the reef to expand," - note the authors of the study. Geologists discovered that earlier, up to 700 thousand years ago, the environmental conditions in the ocean remained unfavorable, which restrained the development of corals.
For the analysis, scientists used proxy data from sedimentary material collected in the Coral Sea 8 kilometers from the edge of the reef. Temperature changes were studied using TEX86H biomarkers — lipids that store information about water temperature. These data illustrate well the summer temperature fluctuations that could have been decisive for coral polyps.
However, the researchers note that for a more complete picture it is necessary to involve additional biomarkers that could confirm the global nature of the findings. Previous studies reconstructed only the last 800 years of ocean history, while the new data cover a much longer period.
These findings raise questions about current projections that predict mass coral die-offs due to global ocean warming. Although modern climate change poses a significant risk to coral ecosystems, historical evidence indicates that periods of warming may also have been periods of reef growth if environmental conditions remained stable.
- The Great Barrier Reef is under threat from climate change
Climate change is seriously threatening the existence of the Great Barrier Reef, causing massive coral bleaching and biodiversity loss. - The Great Barrier Reef cannot be saved
Scientists say that due to the constant increase in ocean temperatures and other environmental factors, the Great Barrier Reef has suffered irreversible damage, which calls into question the possibility of its full recovery.
