Scientists have discovered that ocean anoxia plays a vital role in the world. Triassic–Jurassic This shows that even local deoxygenation can lead to widespread ecosystem collapse. This study highlights the importance of understanding the vulnerability of current marine ecosystems in the face of increasing deoxygenation.
Scientists have made a surprising discovery that sheds new light on the role ocean deoxygenation played in one of the most devastating extinction events in Earth’s history. Their findings have implications for current ecosystems and serve as a warning that the marine environment is likely more fragile than it appears.
The new study was published in a major international journal on November 27th. natural earth sciencesuggests that ocean oxygen depletion played an important role in the destruction of ecosystems and extinction of the marine environment during the Triassic-Jurassic mass extinction, a large-scale extinction event that occurred approximately 200 million years ago. are doing.
But surprisingly, this study shows that the global spread of euxinia, an extreme form of deoxygenation, was similar to today.
Historical background of mass extinction
Earth’s history has been marked by several large-scale mass extinctions, during which global ecosystems collapsed and seed Extinct. All past extinction events appear to have generally coincided with global climate and environmental disturbances that caused ocean deoxygenation. For this reason, marine anoxia has been proposed as a likely cause of marine extinctions at the time, with the assumption that had deoxygenation been more widespread it would have led to a larger extinction event. Based on.
Research methods and findings
The international research team, led by scientists from Royal Holloway (UK), and also including scientists from Trinity College Dublin’s School of Natural Sciences (Ireland) and Utrecht, will explore ancient artifacts from drill cores in Northern Ireland and Germany. Chemical data of mudstone deposits were used. University (Netherlands) was able to connect his two important aspects related to the Triassic-Jurassic mass extinction.
The researchers found that pulses of deoxygenation in shallow marine environments along the edge of continental Europe at the time directly corresponded to increased extinction levels in those locations.
Upon further investigation, the researchers also found, more importantly, that the extent of extreme deoxygenation on a global scale was quite limited and similar to what it is today.
Mika Ruhl, assistant professor in Trinity’s School of Natural Sciences and a member of the research team, said:
“Scientists have long suspected that ocean deoxygenation plays an important role in the disturbance of marine ecosystems, which could lead to the extinction of species in the marine environment. Extreme Studies of historical time intervals of environmental change show that this is indeed the case, and this raises concerns about potential tipping points in local and global ecosystems in response to climate forcing. It teaches us an important lesson.
“Importantly, however, our results show that even if the degree of global deoxygenation is similar to the current level, the progression of local anoxic conditions and subsequent increases in local extinction rates will “We show that this could lead to a cascade of widespread or global ecosystem collapse and extinction. Deoxygenation did not occur.”
Professor Ruhl explained: “This shows that even if only local environments along the edges of continents are disturbed, the global marine ecosystem becomes vulnerable.” Understanding such processes has implications for current ecosystem stability and its associated effects, especially in a world where ocean deoxygenation is predicted to increase significantly in response to global warming and increased nutrient flux from continents. is most important in assessing the food supply. ”
By studying past global change events, such as the transition between the Triassic and Jurassic periods, scientists are disentangling the effects of global climate change and environmental change and understanding the fundamentals controlling tipping points in Earth’s ecosystems. Earth system processes can be constrained.
References: Andrew D. Bond, Alexander J. Dixon, Mika Ruhl, Remko Bos, Bas van de Schootbrugge, “Globally limited but severe shallow shelf during the end-Triassic extinction.” Exinia”, November 27, 2023, natural earth science.
DOI: 10.1038/s41561-023-01303-2