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T.C. Chamberlin Fellow Preston Kemeny leads a new holistic look at Earth’s chemical cycling

March 15, 2024

T.C. Chamberlin Fellow Preston Kemeny is the lead author of a new holistic look at Earth’s chemical cycling that sheds light on how the planet stays habitable. The study mathematically evaluates a suite of biogeochemical processes to identify combinations of reactions that stabilize atmospheric carbon dioxide by balancing fluxes of chemical species among the ocean, atmosphere, and geosphere. Unlike prior modeling efforts, this approach did not prescribe functional relationships between the rates of biogeochemical processes and environmental conditions. Instead, the agnostic framework generates three types of stable reaction combinations: closed sets, where sources and sinks mutually cancel for all chemical reservoirs; exchange sets, where constant ocean – atmosphere conditions are maintained through the growth or destruction of crustal reservoirs; and open sets, where balance in alkalinity and carbon fluxes is accommodated by changes in other chemical components of seawater or the atmosphere. These three modes of operation have different characteristic timescales and may leave distinct evidence in the rock record. Kemeny et al. demonstrate the utility of this framework by applying it to examine and synthesize existing hypotheses for climate change over the last 65 million years. The paper, "Balance and imbalance in biogeochemical cycles reflect the operation of closed, exchange, and open sets" (which also features a contribution from Assistant Professor Clara Blättler, is published in the Proceedings of the National Academy of Sciences.