KOSMOS 2021 Gran Canaria mesocosm study on ocean alkalinity enhancement: phytoplankton metabolic rates


Ocean Alkalinity Enhancement (OAE) could augment long-term carbon storage and mitigate ocean acidification by increasing the bicarbonate ion concentration in ocean water. However, the side effects and/or potential co-benefits of OAE on natural planktonic communities remain poorly understood. To address this knowledge gap, 9 mesocosms were deployed in the oligotrophic waters of Gran Canaria, from September 14th to October 16th, 2021. A CO2-equilibrated Total Alkalinity (TA) gradient was employed in increments of 300 µmol·L-1, ranging from ~2400 to ~4800 µmol·L-1. The carbonate chemistry conditions in terms of TA and Dissolved Inorganic Carbon (DIC), which were then used to calculate pCO2 and pH, and the nitrate+nitrite, phosphate and silicate concentrations were measured every two days over the course of the 33-day experiment alongside the following biotic parameters. Net Community Production (NCP), Gross Production (GP), Community Respiration (CR) rates, as well as the metabolic balance (GP:CR), were monitored every two days through oxygen production and consumption using the winkler method. Fractionated 14C uptake and chlorophyll a were also determined every four days although, initially, the total PO14C and DO14C production were also measured every 4 days, in between, up to day 13. Finally, flow cytometry was also carried out every two days and synecococcus, picoeukaryote and nanophytoplankton abundances were obtained. No damaging effect of CO2-equilibrated OAE in the range applied here, on phytoplankton primary production, community metabolism and composition could be inferred from our results. In fact, a potential co-benefit to OAE was observed in the form of the positive curvilinear response to the DIC gradient up to the ∆TA1800 treatment. Further experimental research at this scale is key to gain a better understanding of the short and long-term effects of OAE on planktonic communities.

DOI https://doi.org/10.1594/PANGAEA.964537
Related Identifier IsSupplementTo https://doi.org/10.5194/egusphere-2023-2409
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.964537
Creator Marín-Samper, Laura ORCID logo; Arístegui, Javier ORCID logo; Hernández-Hernández, Nauzet ORCID logo; Ortiz Cortes, Joaquin ORCID logo; Archer, Stephen ORCID logo; Ludwig, Andrea; Riebesell, Ulf (ORCID: 0000-0002-9442-452X)
Publisher PANGAEA
Publication Year 2024
Funding Reference Helmholtz Association of German Research Centres https://doi.org/10.13039/501100001656 Crossref Funder ID PIE-0021 https://plocan.eu/proyectos/ocean-cdr-ocean-based-carbon-dioxide-removal-strategies Ocean-based carbon dioxide removal strategies; Horizon 2020 https://doi.org/10.13039/501100007601 Crossref Funder ID 731065 https://cordis.europa.eu/project/id/731065 Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean; Horizon 2020 https://doi.org/10.13039/501100007601 Crossref Funder ID 869357 doi:10.3030/869357 OceanNETs: Ocean-based Negative Emission Technologies
Rights Creative Commons Attribution 4.0 International; Data access is restricted (moratorium, sensitive data, license constraints); https://creativecommons.org/licenses/by/4.0/
OpenAccess false
Resource Type Dataset
Format text/tab-separated-values
Size 3828 data points
Discipline Earth System Research
Spatial Coverage (-15.369 LON, 27.990 LAT); Canarias Sea
Temporal Coverage Begin 2021-09-14T00:00:00Z
Temporal Coverage End 2021-10-16T00:00:00Z