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Could artificial reoxygenation revitalize dying coastal seas?

  • C P Slomp*
  • , A Oschlies
  • , A H Altieri
  • , L T Bach
  • , L Bopp
  • , D Breitburg
  • , A Canning
  • , D J Conley
  • , M Dai
  • , B Dewitte
  • , H Enevoldsen
  • , E M Ferrer
  • , A Galán
  • , V Garcon
  • , M Gregoire
  • , B Gustafsson
  • , D Gutierrez
  • , P Handmann
  • , A Hylén
  • , K Isensee
  • R Lamond, M Li, K Limburg, I Montes, J Sterling, A Tan Shau Hwai, J M Testa, D Wallace, J J Waniek, M Yasuhara
*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Abstract

Eutrophication and global warming are key drivers of oxygen loss, also termed deoxygenation, in coastal ecosystems worldwide. Artificial reoxygenation has been suggested as a local or regional solution to increase oxygen concentrations and improve water quality by various parties, including water managers and industry. Three main approaches have been proposed: (1) bubbling with air with the aim to destratify and mix the water column (2) injection of pure oxygen and (3) pumping of oxygenated water to greater water depths (downwelling). In this review, we summarize the results of recent field trials and other implementations of artificial reoxygenation in coastal systems, which, to date, only involve small bays and estuaries. We also discuss potential benefits and risks. While the recent trials indicate that reoxygenation of the water column can be achieved, low oxygen conditions returned rapidly within days to months of discontinuing operations. This illustrates that artificial reoxygenation typically only provides a temporary solution to deoxygenation. Potential side effects of artificial reoxygenation could include enhanced emissions of the greenhouse gas carbon dioxide and, upon bubbling and destratification in shallow waters, also of methane. Additionally, downwelling could lead to warming and an associated increased oxygen demand near the seafloor. Reoxygenation will not necessarily reduce the nutrient availability for phytoplankton, implying that water quality may remain poor. We recommend a careful, case-by-case assessment of the suitability of artificial reoxygenation in coastal systems prior to implementation and monitoring before, during and after each intervention. Any field trials should involve all relevant parties, including scientists and local communities, and results should be reported with full transparency. While in the short-term, artificial reoxygenation may be useful to alleviate oxygen loss in some coastal systems, long-term improvements in the oxygen levels and quality of coastal waters require reductions in nutrient inputs and greenhouse gas emissions. © 2026 The Author(s). Published by IOP Publishing Ltd.
Original languageEnglish
Article number083004
Number of pages12
JournalEnvironmental Research Letters
Volume21
Issue number8
Online published24 Apr 2026
DOIs
Publication statusPublished - Apr 2026

Funding

This paper summarizes the discussion of a workshop on Marine Reoxygenation organized by the IOC-UNESCO Working Group Global Oxygen Network (GO2NE), September 10-11, 2024. CPS acknowledges funding from ERC MARIX 854088. A short summary of the findings of the workshop was published previously as a feature in EOS. BD acknowledges support from ANID (Concurso de Fortalecimiento al Desarrollo Cientıfico de Centros Regionales 2020-R20F0008-CEAZA and Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental COPAS COASTAL FB210021). EMF acknowledges support from the Chancellor’s Postdoctoral Fellowship Program at the University of California Santa Cruz. AG acknowledges support from ANID (Concurso de Fortalecimiento al Desarrollo Científico de Centros Regionales 2020-R20F0008-CEAZA and Coastal Social-Ecological Millennium Institute (SECOS), Millennium Science Initiative Program—Code ICN2019_01). We thank Rita Erven for assistance with the figures. This is UMCES Contribution number 6504 and Ref. No. [UMCES] CBL 2026-040.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

  1. SDG 6 - Clean Water and Sanitation
    SDG 6 Clean Water and Sanitation
  2. SDG 9 - Industry, Innovation, and Infrastructure
    SDG 9 Industry, Innovation, and Infrastructure
  3. SDG 13 - Climate Action
    SDG 13 Climate Action
  4. SDG 14 - Life Below Water
    SDG 14 Life Below Water

Research Keywords

  • artificial reoxygenation
  • coastal waters
  • eutrophication
  • global warming
  • oxygen loss

Publisher's Copyright Statement

  • This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/

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