The rise of marine animals hundreds of millions of years ago had far-reaching implications for the eventual diversity of life on Earth. It also permanently changed the way the oceans store carbon.
In a new study published in the journal Nature, researchers found that at the same time the world’s oceans began to fill with animals with carbonate shells and skeletons, a major shift occurred in how carbonates formed in seawater. Suddenly — and permanently — the oceans were less readily able to precipitate carbonate minerals, or limestone.
The formation of carbonate minerals from dissolved chemicals in seawater allows, over millions of years, for the near-permanent storage of carbon dioxide from the atmosphere.
“We used a mixture of novel geochemical methods and information from sedimentary databases to analyze rocks spanning the entirety of Earth’s history,” said Lidya Tarhan, an assistant professor of Earth and planetary sciences in Yale’s Faculty of Arts and Sciences, and co-corresponding author of the study.
Jiuyuan Wang, an Agouron Geobiology Postdoctoral Fellow in Tarhan’s lab, is first author and co-corresponding author. Co-authors are Noah Planavsky, a Yale professor of Earth and planetary sciences, Andrew Jacobson of Northwestern University, and Amanda Oehlert of the University of Miami.
The researchers also found evidence that a major share of marine carbonates was buried in the deep oceans during Earth’s early history, in contrast to the long-held notion that marine carbonates formed only in shallow waters until the much more recent emergence of calcifying plankton.