Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Arístegui Javier javier.aristegui@ulpgc.es 0000-0002-7526-7741 Faucher Giulia gfaucher@geomar.de 0000-0001-8930-477X GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 Kittu Leila lkittu@geomar.de 0000-0002-3986-8179 GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 Boersma Maarten maarten.boersma@awi.de https://www.awi.de/en/about-us/organisation/staff/single-view/maarten-boersma.html 0000-0003-1010-026X Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (1986-2013) AWI http://www.awi.de https://ror.org/032e6b942 Riebesell Ulf uriebesell@geomar.de https://www.geomar.de/uriebesell/ 0000-0002-9442-452X GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 2026 KOSMOS 2023 Helgoland mesocosm study on ocean alkalinity enhancement: Microbial metabolic rates dataset https://doi.pangaea.de/10.1594/PANGAEA.996213 2026-07-27T10:54:04 Ocean alkalinity enhancement (OAE) is a marine carbon dioxide removal (mCDR) approach that can also mitigate ocean acidification. However, its biological impacts are expected to depend on the magnitude, timing, and dilution of alkalinity additions. To investigate these factors, a mesocosm experiment simulated hydrated lime additions using two six-level alkalinity gradients (up to ΔTA 1250 µmol kg⁻¹): one with immediate full-column mixing and another with mixing delayed by two days. These treatments simulated rapid (e.g. from a moving vessel in open ocean) and slow (e .g. point source or land-based applications in poorly mixed environments)dilution scenarios, representing different hydrodynamic conditions that may occur following real-world alkalinity additions. Gross production (GP), net community production (NCP) and community respiration (CR), determined from in vitro oxygen production and consumption, together with chlorophyll a, were monitored over a 35-day period. Spring bloom initiation was delayed non-linearly at low fCO₂, with reduced absolute and biomass-normalized production occurring in treatments exposed to fCO₂ below ~70 and 30 µatm respectively. These findings indicate that phytoplankton communities may be generally resilient to realistic OAE scenarios while helping to define ecologically relevant fCO₂ thresholds for safe OAE deployment. Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Arístegui Javier javier.aristegui@ulpgc.es 0000-0002-7526-7741 Faucher Giulia gfaucher@geomar.de 0000-0001-8930-477X Kittu Leila lkittu@geomar.de 0000-0002-3986-8179 Boersma Maarten maarten.boersma@awi.de https://www.awi.de/en/about-us/organisation/staff/single-view/maarten-boersma.html 0000-0003-1010-026X Riebesell Ulf uriebesell@geomar.de https://www.geomar.de/uriebesell/ 0000-0002-9442-452X in press Microbial metabolic rates under ocean alkalinity enhancement: A step towards a safe operating space journal article Communications Earth & Environment 7.900000000000001 7.900000000000001 54.183300000000024 54.183300000000024 7.900000000000001 54.183300000000024 2023-03-14T00:00:00 2023-04-17T00:00:00 RETAKE DAM CDRmare - RETAKE: CO2 removal by alkalinity enhancement: potential, benefits and risks https://retake.cdrmare.de/en/ GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 OceanAlkAlign Ocean Alk-Align https://alkalign.ocean.dal.ca/ Dalhousie University https://ror.org/01e6qks80 OceanNETs Ocean-based Negative Emission Technologies https://www.oceannets.eu GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 CDRmare Research Mission of the German Marine Research Alliance (DAM): Marine carbon sinks in decarbonisation pathways https://cdrmare.de/en/ GEOMAR - Helmholtz Centre for Ocean Research Kiel GEOMAR http://www.geomar.de https://ror.org/02h2x0161 Federal Ministry of Education and Research BMBF https://www.bmftr.bund.de https://doi.org/10.13039/501100002347 03F0895A DAM CDRmare - RETAKE, GEOMAR https://foerderportal.bund.de/foekat/jsp/SucheAction.do?actionMode=view&fkz=03F0895A Horizon 2020 of the European Commission H2020 https://research-and-innovation.ec.europa.eu/funding/funding-opportunities/funding-programmes-and-open-calls/horizon-2020_en https://doi.org/10.13039/501100007601 731065 Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean https://doi.org/10.3030/731065 Horizon 2020 of the European Commission H2020 https://research-and-innovation.ec.europa.eu/funding/funding-opportunities/funding-programmes-and-open-calls/horizon-2020_en https://doi.org/10.13039/501100007601 869357 OceanNETs: Ocean-based Negative Emission Technologies doi:10.3030/869357 KOSMOS_2023_Mesocosm-M1 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M2 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment KOSMOS_2023_Mesocosm-M3 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M4 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment KOSMOS_2023_Mesocosm-M5 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M6 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment KOSMOS_2023_Mesocosm-M7 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M8 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment KOSMOS_2023_Mesocosm-M9 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M10 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment KOSMOS_2023_Mesocosm-M11 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg KOSMOS_2023_Mesocosm-M12 54.1833 7.9 Helgoland 2023-03-14T00:00:00 2023-04-21T00:00:00 KOSMOS_2023 KOSMOS_2023 KOSMOS Helgoland KOSMOS Helgoland 2023-03-13T00:00:00 2023-03-13 2023-04-21T00:00:00 2023-04-21 Riebesell, Ulf Riebesell, Ulf Mesocosm experiment MESO http://invabio.wdc-mare.org/mesocubi.jpg delayed treatment 2798 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Type of study Study type type Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Study type Event label Event Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Event Day of experiment DOE day day Time T http://dbpedia.org/resource/Time Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 DOE [day] DATE/TIME Date/Time http://en.wikipedia.org/wiki/ISO_8601 Time T http://dbpedia.org/resource/Time Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Date/Time Identification number ID no Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Mesocosm number ID no Treatment: dilution type T:dilution treatment Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Dil_Treat T:dilution Treatment: alkalinity, total T:AT µmol/kg treatment total https://www.oxforddictionaries.com/definition/american_english/total Molar Concentration Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Delta_TA T:AT [µmol/kg] Treatment Treat treatment Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Treat Sample code/label Sample label Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Sample label Respiration rate, oxygen, community Comm resp O2 µmol/l/day respiration rate http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100415939?rskey=tF1NrR&result=2 oxygen O https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:25805 Reaction Rate Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 CR: Community Respiration (amount of oxygen respired in the dark) Comm resp O2 [µmol/l/day] Net community production of oxygen NCP O2 µmol/l/day https://doi.org/10.1029/2007GB003095 net community production NCP oxygen O https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:25805 Reaction Rate Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 NCP O2 [µmol/l/day] Gross community production of oxygen GCP O2 µmol/l/day oxygen O https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:25805 Reaction Rate Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 GCP O2 [µmol/l/day] Balance Balance balance http://purl.obolibrary.org/obo/PATO_0000185 Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 GPR: Metabolic Balance = GCP/CR Balance Depth, description Depth desc depth http://purl.obolibrary.org/obo/PATO_0001595 description Marín-Samper Laura laura.marin@ulpgc.es 0000-0002-6825-0992 Depth desc CurationLevelC Enhanced curation https://wiki.pangaea.de/wiki/Curation_levels metabolic rates ocean alkalinity enhancement Ocean Alkalinity Enhancement (OAE) Phytoplankton Primary production geomar author103704 author103946 author10403 author21895 author53772 author78372 award2769 award3077 award335 campaign3395033 campaign52642 curlevel30 event3299309 event3299310 event3299311 event3299312 event3299313 event3299314 event3299315 event3299316 event3299317 event3299318 event3299319 event3299320 funder20473 funder20475 geocode1599 geocode1600 geocode1601 inst20147 inst20269 inst21772 journal17037 license21 method11277 param128037 param128262 param185520 param24327 param501856 param521016 param527839 param551091 param78394 param790 param91529 param96278 pi103946 project4757 project4768 project4784 project5044 ref140819 term1073131 term1074310 term242 term38253 term38494 term38497 term40710 term41013 term41171 term43975 term44030 term44031 term47694 term48982 term49506 term50714 term71465 term73463 term77452 term833