In a new special collection on Deep Carbon Science in the online journal Frontiers, deep carbon researchers within and beyond the DCO community had the opportunity to contribute findings from their work on the slow, deep carbon cycle . DCO members from all four research communities edited the collection, including Isabelle Daniel (Université Claude Bernard Lyon 1, France), Sabin Zahirovic (University of Sydney, Australia), Dan Bower (University of Bern, Switzerland), Artur Ionescu (Babeș-Bolyai University, Romania), Mattia Pistone (Université de Lausanne, Switzerland), Sami Mikhail (University of St. Andrews, UK), and Dawn Cardace (University of Rhode Island, USA).
“DCO has been beneficial for the entire community and has stimulated a lot of research activities around the world on carbon within the deep Earth,” said Daniel. “This collection gives an opportunity to the larger community to participate in the synthesis activities of the DCO.”
The special collection includes research spanning the four DCO research areas, and once complete, will have at least 20 new papers. Ultimately the collection will feature contributions from more than 100 authors, many of whom are early-career scientists. With such diverse contributors, the collection complements other DCO synthesis products, such as the Deep Carbon: Past to Present book and the Nature Deep Carbon Collection, written by other DCO-affiliated scientists.
Among the many notable contributions in the collection is a paper published posthumously by Louise Kellogg (University of California, Davis, USA) and colleagues. They demonstrate the importance of the crust as a reservoir for storing atmospheric carbon dioxide that dissolves into rainwater, which is a factor frequently overlooked in climate modeling. They also use a previous warm period, the Paleocene-Eocene thermal maximum (PETM) to show how elevated temperatures sped up the rate of carbon storage.
The structure of carbon compounds in the mantle is an important topic touched on by several papers in the collection. One recent major advance is the discovery that in the deepest parts of Earth, carbon and oxygen shift from the familiar carbonate structure of a carbon atom bonded to three oxygen atoms, to a tetrahedral structure with four oxygen atoms. A paper by Chrystèle Sanloup (IMPMC, Sorbonne Université, France) and colleagues shows that these melted tetrahedral carbonates react poorly with silicates, which may help carbon compounds persist and move within the deep mantle. Sudeshna Basu (University College London, UK) et al. also found that shale holds onto its carbon as it sinks and heats up, especially if that carbon has been biomineralized, such as the carbon in seashells.
Additionally, Philip Eickenbusch (ETH Zürich, Switzerland) and colleagues discovered that organic acids found in mud volcanoes in the Mariana Trench come from serpentinization reactions between water and certain rocks, rather than from microbes, as had been thought previously.
A paper by Kevin Wong (University of Leeds, United Kingdom) and collaborators looks at how much carbon enters the mantle in different settings where tectonic plates meet or split open. They find that more carbon has degassed from the mantle during the past 200 million years than has entered due to subduction, but that there is still uncertainty regarding how much carbon is stored in the crust and how much escapes through continental rifts.
All the papers in the collection are open access so that they can be read and shared freely by scientists everywhere. The papers in the collection already have amassed more than 31,000 views from readers from six continents.
“The collection has really engaged our colleagues outside of DCO and enabled them to be a part of this major endeavor,” said Daniel, “and that’s been really fantastic.”
Table of contents
Click on the titles below to access the papers.