Scientists are unraveling the interactions between early life on Earth and the environment for 500 million years.

The atmosphere, oceans and life on Earth have interacted over the past 500 million years in ways that have improved the conditions for early life to thrive. Now, an interdisciplinary team of scientists has produced a visionary paper on this evolutionary history, published in National Science Review.

“One of our tasks was to summarize the most important discoveries about carbon dioxide and oxygen in the atmosphere and ocean over the last 500 million years,” says the professor of anthropology of Syracuse University Zunli Lu, lead author on the paper. “We looked at how those physical changes affected the evolution of life in the ocean. But it’s a two-way street. The evolution of life also affected the chemical environment. It’s not a job young to understand how to build a world that can last a long time.”

A team from Syracuse University, Oxford University and Stanford University examined the complexities among ancient life forms, including plants and animals, and chemical ecosystems in the current Phanerozoic Eon. , which began about 540 million years ago.

At the beginning of the Phanerozoic, carbon dioxide levels in the atmosphere were high, and oxygen was low. Such a situation would be difficult for most modern things to succeed. But seaweed changed that. They absorbed carbon dioxide from the atmosphere, locked it in living things and produced oxygen through photosynthesis.

The ability of animals to survive in the marine environment was affected by oxygen levels. Lu is studying when ocean oxygen levels may have risen or fallen during the Phanerozoic using geochemical proxies and model simulations. Co-author Jonathan Payne, a professor of Earth and planetary science at Stanford University, compares the recovery needs of estimated ancient animals with the places they survived or disappeared from the fossil record. the old ones.

When photosynthetic algae removed atmospheric carbon from sedimentary rocks to lower carbon dioxide and raise oxygen levels, the algae’s enzymes slowed down to fix the carbon. Therefore, algae had to develop complex mechanisms to carry out photosynthesis in low carbon dioxide and high oxygen levels, and achieved this by creating internal photosynthesis units with control over k’ hemisphere.

“For algae, it’s changes in the environmental ratio of O₂/CO₂ that seems to be the key to improving photosynthetic efficiency,” says co-author Rosalind Rickaby, who is a professor of paleontology at Oxford. life forms.”

Ancient photosynthesizers had to adapt to changes in the environment they themselves created, says Lu. “The first part of Phanerozoic history is increasing life, and the second part is adaptation.”

If scientists want to further understand this interaction between life and the physical environment, as well as the drivers and limits of survival, the authors suggest that mapping the spatial patterns of ocean oxygen , biomarkers for photosynthesis and metabolic tolerance of animals shown in the fossil record. will be an important future research direction.