Unifying framework for assessing sensitivity for marine calcifiers to ocean alkalinity enhancement identifies winners, losers and biological thresholds – importance of caution with precautionary principle
Ocean alkalinity enhancement (OAE), one of the marine carbon dioxide removal strategies, is gaining importance in its role towards alleviating the consequences of climate change as well as mitigating against ocean acidification (OA). OAE is based on adding alkalinity to open-ocean and coastal marine...
| Main Authors: | , , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2024
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/egusphere-2024-947 https://noa.gwlb.de/receive/cop_mods_00072916 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00071105/egusphere-2024-947.pdf https://egusphere.copernicus.org/preprints/2024/egusphere-2024-947/egusphere-2024-947.pdf |
| Summary: | Ocean alkalinity enhancement (OAE), one of the marine carbon dioxide removal strategies, is gaining importance in its role towards alleviating the consequences of climate change as well as mitigating against ocean acidification (OA). OAE is based on adding alkalinity to open-ocean and coastal marine systems through a variety of different approaches, which raises carbonate chemistry parameters (such as pH, total alkalinity, aragonite saturation state), and enhances the uptake of carbon dioxide (CO2) from the atmosphere. There are large uncertainties in both short- and long-term outcomes related to potential environmental impacts, which would ultimately decide on the success of OAE as a climate strategy. This paper represents a meta-analyses effort, leveraging on the OA studies, data, observed patterns and generalizable responses. We propose a conceptual framework of categorized responses that are predicted under OAE implementation. The synthesis was done using raw experimental OA data based on 96 collected studies, capturing the responses of eleven biological groups (coralline algae, corals, dinoflagellates, mollusks, gastropods, pteropods, coccolithophores, annelids, crustacean, echinoderms, and foraminifera), using regression analyses to predict biological responses and thresholds to NaOH or Na2CO3 concentrations. Predicted responses were categorized into six different categories (linear positive and negative, threshold positive and negative, parabolic and neutral) to delineate species- and group-specific responders: 40 % of species are predicted to respond positively (N=38), 20 % of species negatively (N=20), and 40 % (N=38) were found to demonstrate a neutral response upon alkalinity addition. For negatively impacted species, biological thresholds corresponding to 10 to 500 µmol/kg NaOH addition were found, occurring at much lower values than previously expected. Such lower threshold values represent realistic conditions related to OAE field deployments but contrast with the conditions where current OAE lab ... |
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