Dominik Hülse / UCR
–
UC Riverside Earth system modeler Dominik Hülse reacts to hydrogen sulfate.
–
Nationalgeographic.co.id—According to a new study by scientists, tiny microbes emitting toxic gases have helped cause and prolong the largest mass extinction in Earth’s history.
The extreme warming that occurred at the end of the Permian has had profound changes in marine biogeochemical cycles and animal habitation. This change resulted in the largest metazoan extinction in Earth’s history. However, the causal mechanism of the extinction consistent with various proxy records of geochemical conditions over the interval has not been determined with certainty.
Previously, scientists thought and believed that Siberian volcanoes spewing greenhouse gases played a role in driving the mass extinction event about 250 million years ago, at the end of the Permian period. These gases cause extreme warming, which in turn causes 80% of all marine species, as well as many terrestrial species, to become extinct.
Until now, scientists have not been able to explain exactly how the heat caused the death. A new study led by scientists from UC Riverside has been published in the journal Nature Geoscience on October 28, 2021 with the title End-Permian marine extinction due to temperature-driven nutrient recycling and euxinia. This study shows that heat has accelerated the metabolism of microbes, thus creating lethal conditions.
“Once oxygen in the ocean is used to decompose organic matter, microbes begin to ‘breathe’ sulfate and produce hydrogen sulfide, a gas that smells like rotten eggs and is toxic to animals,” said Dominik Hülse, modeler of the UC Riverside Earth system.
As marine photosynthesis takes place, the microbes and plants that form the basis of the food chain decompose, other microbes quickly consume oxygen and leave less oxygen for larger organisms. When finally there is no oxygen, the microbes consume the sulfate which then releases a poison, smelling hydrogen sulfide, or H2S, creating a more extreme condition called euxinia. This condition is sustained by the release of nutrients during decomposition, encouraging the production of more organic matter that helps maintain this cycle of toxic and odors.
“Our research shows that the entire ocean is not euxinic. These conditions begin in the deeper parts of the water column. As temperatures increase, the euxinic zone becomes larger, more toxic, and rises up the water column into the shelf environment where most marine animals live, then poison them.” Hülse said.
This expanding euxinic zone can be detected by researchers through chemical signatures in sediment samples.
Oxygen depletion is an ongoing problem today and is sure to get worse under future climate change. Euxinic waters can be found in places like the 16-mile-long Dominguez Channel in Los Angeles County, where the September 2021 warehouse fires released ethanol. Ethanol kills vegetation in the drains, which decomposes and is consumed by microbes. They then produce hydrogen sulfide at toxic levels. Thousands of people breathing in the foul-smelling river reported vomiting, diarrhea, insomnia, dizziness, headaches, sneezing and other symptoms.
Also Read: Dirt-eating bacteria could potentially save famous works of art
Martin Mergili
–
Could a supervolcanic eruption in Siberia today be the cause of the mass extinction 250 million years ago?
–
Wikipedia
–
Diagram of the euxinia mechanism in the Canfield Sea.
–
These lessons from the ancient world may be crucial to understanding the processes that challenge our modern oceans and waterways.
“It would be speculative to place an ancient mass extinction event on the planet today,” Hülse said.
“However, this study shows us that the ocean’s response to higher concentrations of carbon dioxide in the atmosphere may be underestimated.” he concluded.
Also Read: Can Microbes Communicate with Alien Species Like Aliens?
PROMOTED CONTENT
Featured Videos
– .
