The findings, which appear this week in the Proceedings of the National Academy of Sciences, could explain how calcium carbonate dissolves in shallow layers of the ocean, where scientists had assumed it should remain intact. The results could also change scientists’ understanding of how quickly the ocean can sequester carbon from the atmosphere.

Marine snow is a main vehicle by which the ocean stores carbon. At the ocean’s surface, phytoplankton absorb carbon dioxide from the atmosphere and convert the gas into other forms of carbon, including calcium carbonate — the same stuff that’s found in shells and corals. When they die, bits of phytoplankton drift down through the ocean as marine snow, carrying the carbon with them. If the particles make it to the deep ocean, the carbon they carry can be buried and locked away for hundreds to thousands of years.

Our planet plunged into one of the most dramatic climate states in its long history, approximately 720–635 million years ago. During a period geologists call Snowball Earth, ice sheets crept from the poles all the way to the tropics, covering the oceans and continents in a nearly global freeze.

Researchers believe shifting wind systems may help explain the mystery. Dr. Harald Hofmann, a co-author from the Commonwealth Scientific and Industrial Research Organisation (CSIRO), says regional wind patterns likely influenced where rainfall ultimately ended up.

"Prior research shows Minjerribah also experienced heavy rainfall events at this time, but, because of south-east trade winds that were occurring at the time, rainfall from the south only fed into lakes on Minjerribah, not those on K'gari," he says.

cross-posted from: https://sopuli.xyz/post/41716172

“The goal of this research was really just to understand where in the world this is happening,” said Elise Mazur, a researcher with the Land and Carbon Lab at the World Resources Institute and one of the report’s authors. “We know where deforestation is occurring. But we were less sure about where non-forest ecosystems are being lost.”

https://www.pnas.org/doi/abs/10.1073/pnas.2521183123