Environmental impacts of ocean alkalinity enhancement
Environmental impacts of ocean alkalinity enhancement
Editor(s): Tyler Cyronak, Lydia Kapsenberg, Jaime Palter, Kai G. Schulz, and Patricia Grasse

Ocean alkalinity enhancement is one of several ocean-based carbon dioxide removal (CDR) approaches that are currently under evaluation. By increasing alkalinity of the seawater, dissolved carbon dioxide is converted to bicarbonate and carbonate ions, thereby allowing alkalinity-enhanced seawater to absorb more carbon dioxide from the atmosphere.

There are several different methods by which ocean alkalinity can be enhanced. These include the spreading of fine-grained natural or manufactured minerals in coastal or open-ocean settings, electrochemical production of alkaline compounds, electrochemical removal of hydrochloric acid, and a combination of the aforementioned, among others. Following the alkalinity enhancement, either carbon dioxide is absorbed passively from the atmosphere through natural air–sea gas exchange dynamics or carbon dioxide sourced from the atmosphere may be added directly to treated water prior to its release into the ocean. While ocean alkalinity enhancement could be an effective, durable, and scalable CDR strategy, the environmental impacts, both intended and unintended, are not well understood.

This special issue explores a range of biological and ecological impacts associated with alkalinity enhancement and approaches for monitoring strategies in order to safely scale scientific research in the field. The target audience of this special issue includes not only the ocean alkalinity enhancement research community but also those involved in making decisions about the funding, permitting, and monitoring of potential field trials and pilot-scale studies. In keeping with our mission to publish all valid research, we consider negative and null results.

Submission is open to research within, but is not limited to, the following scope:

  • biological and ecological impacts of ocean alkalinity enhancement, including those related to secondary abiotic changes (changes in trace metal concentrations, turbidity, etc.) as documented through manipulative lab, mesocosm, and field experiments; natural analogues; and computer models;
  • mitigation of harmful biological or ecological impacts associated with ocean acidification;
  • reversibility of harmful biological or ecological impacts;
  • spatial differences in biological or ecological impacts across ocean regions or habitats;
  • discussion and/or modelling of environmental monitoring strategies for field trials, pilot studies, or large-scale applications;
  • review papers or meta-analyses on any of the above.

The following related topics are out of scope:

  • research focused solely on abiotic processes (e.g. dissolution kinetics, estimates of CO2 removal potential),
  • techno-economic and life-cycle analyses,
  • social impact studies.

To accelerate high-quality submissions, the first 10 accepted manuscripts (limited to two publications per research grant) will be offered financial support of up to  1800 Euro to offset either publication fees or costs for conference travel.

Financial support is provided the Ocean Alkalinity Enhancement (OAE) R&D Program, a multi-funder effort incubated by Additional Ventures and fiscally sponsored by the Windward Fund. The Program is partnering with CEA Consulting to support this Special Issue. Please direct all questions to Lydia Kapsenberg (lydia(at)ceaconsulting.com).

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27 Nov 2023
Responses of globally important phytoplankton species to olivine dissolution products and implications for carbon dioxide removal via ocean alkalinity enhancement
David A. Hutchins, Fei-Xue Fu, Shun-Chung Yang, Seth G. John, Stephen J. Romaniello, M. Grace Andrews, and Nathan G. Walworth
Biogeosciences, 20, 4669–4682, https://doi.org/10.5194/bg-20-4669-2023,https://doi.org/10.5194/bg-20-4669-2023, 2023
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18 Oct 2023
Assessing the impact of CO2 equilibrated ocean alkalinity enhancement on microbial metabolic rates in an oligotrophic system
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, Joaquín Ortiz, Steve D. Archer, Andrea Ludwig, and Ulf Riebesell
EGUsphere, https://doi.org/10.5194/egusphere-2023-2409,https://doi.org/10.5194/egusphere-2023-2409, 2023
Preprint under review for BG (discussion: open, 1 comment)
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18 Sep 2023
Influence of Ocean Alkalinity Enhancement with Olivine or Steel Slag on a Coastal Plankton Community in Tasmania
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
EGUsphere, https://doi.org/10.5194/egusphere-2023-2120,https://doi.org/10.5194/egusphere-2023-2120, 2023
Preprint under review for BG (discussion: final response, 4 comments)
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12 Sep 2023
Investigating the effect of silicate and calcium based ocean alkalinity enhancement on diatom silicification
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart Thomas Bach
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-144,https://doi.org/10.5194/bg-2023-144, 2023
Preprint under review for BG (discussion: final response, 2 comments)
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21 Aug 2023
Phytoplankton Response to Increased Nickel in the Context of Ocean Alkalinity Enhancement
Xiaoke Xin, Giulia Faucher, and Ulf Riebesell
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-130,https://doi.org/10.5194/bg-2023-130, 2023
Revised manuscript under review for BG (discussion: final response, 4 comments)
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17 Aug 2023
Biological impact of ocean alkalinity enhancement of magnesium hydroxide on marine microalgae using bioassays simulating ship-based dispersion
Stephanie Delacroix, Tor Jensen Nystuen, Erik Höglund, and Andrew L. King
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-138,https://doi.org/10.5194/bg-2023-138, 2023
Revised manuscript under review for BG (discussion: final response, 10 comments)
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