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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Ocean Observation
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1418634
This article is part of the Research Topic Aerosol Deposition in the Ocean: Drivers and Biogeochemical Effects View all 4 articles

Contemporary decline in northern Indian Ocean primary production weakly offset by rising atmospheric nitrogen deposition

Provisionally accepted
Manon Malsang Manon Malsang 1,2*Laure Resplandy Laure Resplandy 2,3*Laurent Bopp Laurent Bopp 4,5,6*Yangyang Zhao Yangyang Zhao 3*Sam Ditkovsky Sam Ditkovsky 2*Fan Yang Fan Yang 3Fabien Paulot Fabien Paulot 7Marina Lévy Marina Lévy 1*
  • 1 UMR7159 Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques (LOCEAN), Paris, France
  • 2 Department of Geosciences, Princeton University, Princeton, New Jersey, United States
  • 3 High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, United States
  • 4 Laboratoire de Météorologie Dynamique, Sorbonne Université (CNRS), Paris, Île-de-France, France
  • 5 École Normale Supérieure, Paris, Ile-de-France, France
  • 6 École Polytechnique, Palaiseau, France
  • 7 Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, New Jersey, United States

The final, formatted version of the article will be published soon.

    Since 1980, atmospheric pollutants in South Asia and India have dramatically increased in response to industrialization and agricultural development, enhancing the atmospheric deposition of anthropogenic nitrogen in the northern Indian Ocean and potentially promoting primary productivity. Concurrently, ocean warming has increased stratification and limited the supply of nutrients supporting primary productivity. Here, we examine the biogeochemical consequences of increasing anthropogenic atmospheric nitrogen deposition and contrast them with the counteracting effect of warming, using a regional ocean biogeochemical model of the northern Indian Ocean forced with atmospheric nitrogen deposition derived from an Earth System Model. Our results suggest that the 60% recent increase in anthropogenic nitrogen deposition over the northern Indian Ocean provided external reactive nitrogen that only weakly enhanced primary production (+ 10 mg C.m-2.d-1.yr-1 in regions of intense deposition) and secondary production (+4 mg C.m-2.d-1.yr-1). However, we find that locally this enhancement can significantly offset the declining trend in primary production over the last four decades in the central Arabian Sea and western Bay of Bengal, whose magnitude are up to -20 and -10 mg C.m-2.d-1.yr-1 respectively.

    Keywords: Atmospheric deposition, primary production, export, Indian Ocean, biogeochemical cycling, Anthropogenic Aerosols, Nutrients, Fertilization

    Received: 16 Apr 2024; Accepted: 23 Oct 2024.

    Copyright: © 2024 Malsang, Resplandy, Bopp, Zhao, Ditkovsky, Yang, Paulot and Lévy. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Manon Malsang, UMR7159 Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques (LOCEAN), Paris, France
    Laure Resplandy, Department of Geosciences, Princeton University, Princeton, 08544, New Jersey, United States
    Laurent Bopp, Laboratoire de Météorologie Dynamique, Sorbonne Université (CNRS), Paris, 75005, Île-de-France, France
    Yangyang Zhao, High Meadows Environmental Institute, Princeton University, Princeton, 08544, New Jersey, United States
    Sam Ditkovsky, Department of Geosciences, Princeton University, Princeton, 08544, New Jersey, United States
    Marina Lévy, UMR7159 Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques (LOCEAN), Paris, France

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