A RUpture‐Based detection method for the Active mesopeLagIc Zone (RUBALIZ): A crucial step toward rigorous carbon budget assessments

Autor: Robin Fuchs, Chloé M. J. Baumas, Marc Garel, David Nerini, Frédéric A. C. Le Moigne, Christian Tamburini
Přispěvatelé: Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques de Marseille (I2M), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), This manuscript is a contribution of the APERO project funded by the National Research Agency under the grant APERO [grant number ANR ANR-21-CE01-0027] and by the French LEFE-Cyber program (CNRS, INSU)., ANR-21-CE01-0027,APERO,Estimer la production, l'export et la reminéralisation de la matière marine biogène : de la surface à l'océan profond(2021)
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Limnology And Oceanography-methods (1541-5856) (Wiley), 2023-01, Vol. 21, N. 1, P. 24-39
Limnology and Oceanography: Methods
Limnology and Oceanography: Methods, 2022, ⟨10.1002/lom3.10520⟩
ISSN: 1541-5856
DOI: 10.1002/lom3.10520⟩
Popis: International audience; Determining mesopelagic organic carbon budgets is essential to characterize the ocean's role as a carbon dioxide sink. This is because the biological processes observed in the mesopelagic zone are crucial for understanding the biological carbon pump. Yet, field assessments of carbon budgets are often unbalanced with the carbon demand exceeding its supply. This underlines either methodological issues in the budget calculations or incomplete knowledge of the mesopelagic carbon cycling with potentially missing sources. Carbon budgets are built by partitioning the ocean into vertical depth zones. Vertical boundaries are conventionally defined between 200 and 1000 m depth or using various thresholds. Such approaches lack consistent methodology preventing robust comparison of mesopelagic carbon budget from region to region. Here, using a statistical rupture detection method applied to conductivity-temperature-depth (CTD)-cast variables (fluorescence, O 2 concentration, potential temperature, salinity, and density), we aim to provide independent estimates of mesopelagic boundaries. We demonstrate that the so-determined upper boundary is highly correlated with the knee points of the particulate organic carbon (POC) fluxes estimated by a power law and that over 90% of the POC flux attenuation occurs within our method boundaries. The identified zone therefore corresponds to the most active part of the conventional mesopelagic zone and we name it the "active mesopelagic zone" (AMZ). We find that the depths of the mesopelagic zone depend on the region considered. Our results demonstrate that the mesopelagic carbon budget discrepancy can vary up to four folds depending on the boundaries chosen and hence provide novel grounds to reassess existing and future mesopelagic carbon budgets.
Databáze: OpenAIRE
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