Kristen Wilson / Earth & Environmental Sciences / Faculty Mentor: Arne Winguth
The marine carbon cycle is of importance to sequester carbon dioxide from the atmosphere into the ocean. A substantial oceanic carbon reservoir is that of dissolved organic carbon (DOC) in labile (LDOC), semilabile, and refractory DOC (RDOC) form. This paper investigates the critical role of microbial activity in the Community Earth System Model (CESM) to enhance predictions of carbon sequestration, particularly in the bathypelagic zone. The microbial loop, dependent on temperature, bacterial biomass, mortality rates, and metabolic activity, is integrated into CESM2.1.5, that has updated the Marine Biogeochemistry Library (MARBL). Preliminary results reveal an improved prediction simulating deep ocean carbon, but model-data biases remain linked to both limitations of predicting the microbial loop as well uncertainties in the observations. Discrepancies exist primarily in the deep ocean below 1,000m, and discrepancies of 2-4uM exist in all oceans. The study aims to improve predictions of DOC abundance, with implications for understanding ocean stratification, changes in oceanic particle fluxes. This study aims to quantify changes of the ecosystem and microbial loop in a changing climate and the impact on carbon storage. Ongoing and future experiments will explore the microbial loop’s influence on DOC’s residence time in the ocean, parameterization of bacteria’s temperature sensitivity, and the microbial loop’s responses to climate-induced changes.
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