The modeler reacted to the scent of hydrogen sulfide. Credit: Dominik Hlse/UCR
The biggest mass extinction in Earth's history may have been caused by tiny microbes burping toxic gas.
The mass extinction event is thought to have been caused by greenhouse gases from the Siberia volcanos. 80% of all marine species and many land species went extinct because of the gases.
Scientists were not able to explain how the heat caused the deaths. The heat accelerated the metabolisms of the organisms, creating deadly conditions.
"After oxygen in the ocean was used up to break down organic material, microbes began to breathe sulfate and produce hydrogen sulfide, a gas that smells like rotten eggs and is poisonous to animals," said UC Irvine Earth system modeler Dominik Hlse.
Oxygen was quickly consumed by other microbes as ocean photosynthesizers wererotted, leaving little of it for larger organisms. In the absence of oxygen, the microbes consumed sulfate and then expelled toxic, H2S, creating an even more extreme condition called euxinia. The production of more organic material helped to maintain this stinky, toxic cycle, as the release of nutrients during decomposition helped to sustain these conditions.
The entire ocean wasn't euxinic. Hlse said that the conditions began in the deeper parts of the water column. The euxinic zones got bigger and more toxic as temperatures increased, and moved up the water column into the shelf environment where most marine animals lived.
The expanding euxinic zones can be detected with the help of chemical signatures.
Climate change is bound to make the problem of oxygen depletion worse. There are waters in the Los Angeles County's 16-mile-long Dominguez Channel that contain euxinic waters. The vegetation was killed by the alcohol. They made hydrogen sulfide at toxic levels. Thousands of people in the breathing range of the river reported symptoms such as vomiting, dizziness, insomnia, headaches, sneezing, and other symptoms.
Lessons from the ancient world may help us understand the processes that are challenging our modern oceans and waterways.
Hlse said that it would be speculative to superimpose the ancient mass extinction event on today's planet. The study shows that the ocean's response to higher carbon dioxide concentrations may be underestimated.
The End-Permian marine extinction is due to temperature-driven nutrient recycling and euxinia. The DOI is 10.1038/s41561-021-0
The journal information is Nature Geoscience.
The stinkiest period in Earth's history was retrieved from December 20 to December 20.
The document is copyrighted. Any fair dealing for the purpose of private study or research cannot be reproduced without written permission. The content is not intended to be used for anything other than information purposes.
