Biological carbon pump estimate based on multidecadal hydrographic data.

Autor: Wang WL; State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China. weilei.wang@xmu.edu.cn., Fu W; Department of Earth System Science, University of California, Irvine, Irvine, CA, USA.; Department of Atmospheric and Oceanic Science, Fudan University, Shanghai, China., Le Moigne FAC; Univ Brest, CNRS, IRD, Ifremer, LEMAR, Plouzané, France., Letscher RT; Earth Sciences and Ocean Process Analysis Laboratory, University of New Hampshire, Durham, NH, USA., Liu Y; Department of Earth System Science, University of California, Irvine, Irvine, CA, USA.; Department of Geosciences, Princeton University, Princeton, NJ, USA., Tang JM; State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China., Primeau FW; Department of Earth System Science, University of California, Irvine, Irvine, CA, USA. fprimeau@uci.edu.
Jazyk: angličtina
Zdroj: Nature [Nature] 2023 Dec; Vol. 624 (7992), pp. 579-585. Date of Electronic Publication: 2023 Dec 06.
DOI: 10.1038/s41586-023-06772-4
Abstrakt: The transfer of photosynthetically produced organic carbon from surface to mesopelagic waters draws carbon dioxide from the atmosphere 1 . However, current observation-based estimates disagree on the strength of this biological carbon pump (BCP) 2 . Earth system models (ESMs) also exhibit a large spread of BCP estimates, indicating limited representations of the known carbon export pathways 3 . Here we use several decades of hydrographic observations to produce a top-down estimate of the strength of the BCP with an inverse biogeochemical model that implicitly accounts for all known export pathways. Our estimate of total organic carbon (TOC) export at 73.4 m (model euphotic zone depth) is 15.00 ± 1.12 Pg C year -1 , with only two-thirds reaching 100 m depth owing to rapid remineralization of organic matter in the upper water column. Partitioned by sequestration time below the euphotic zone, τ, the globally integrated organic carbon production rate with τ > 3 months is 11.09 ± 1.02 Pg C year -1 , dropping to 8.25 ± 0.30 Pg C year -1 for τ > 1 year, with 81% contributed by the non-advective-diffusive vertical flux owing to sinking particles and vertically migrating zooplankton. Nevertheless, export of organic carbon by mixing and other fluid transport of dissolved matter and suspended particles remains regionally important for meeting the respiratory carbon demand. Furthermore, the temperature dependence of the sequestration efficiency inferred from our inversion suggests that future global warming may intensify the recycling of organic matter in the upper ocean, potentially weakening the BCP.
(© 2023. The Author(s).)
Databáze: MEDLINE
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