Action #1: Solubility and biological pumps

Objectives: Study air-sea CO2 fluxes and pH using several tools/approaches to understand their variability and main drivers in an area where there is a sparseness of carbonate system data, pH trends are unknown and the existing AT-S relationships are inadequate. The action targets an optimum strategy in the area to understand its role as source or sink of CO2 as well as the links between carbon, nutrients cycles and primary productivity.

Action Lead and other Partners (with contact persons): HCMR (Frangoulis), NIVA (King, Marty)

JS3 Platforms included: a) For carbonate variables: Core platforms: HCB, Ferrybox, Additional platforms: monitoring by R/V at HCB, Calibration lab (for pH analysis), lab for CT/AT analysis. b) For carbonate associated/interpretation variables. Core platforms: HCB, E1-M3A, Glider, Mykonos buoy or Saronikos Buoy. Additional platforms: Argo float data (when available in the area), satellite data.

Other data sources and external partners for implementation: Other data includes, a) simulated sea surface pH, pCO2, and PP from HCMR 3-D coupled model, b) nearby atmospheric station Finokalia (air pCO2) and nearest ICOS marine stations and c) estimates of carbonate system variables from temperature and salinity using existing or improved (see action #5) regional algorithms.

Overall timetable of action:

Dec 2020 to Aug 2022: Carbonate system data collection from HCB (fixed platform + RV visits).

Jan 2022: Submission of CO2 data to SOCAT.

Οct 2021 to Aug 2022: Carbonate system data collection activities expanded to Ferrybox.

June 2022 to Aug 2022: Estimates of carbonate system variables from optimum algorithms.

Description of action: 

Key PPS features: Capacity to provide additional EOVs at the required resolution. Multi-interface coverage. Collaboration elements: i) transfer of knowledge from other partners, ii) connecting with other regional initiatives measuring carbon parameters and iii) linking observations with modelling.

Measurement of carbonate variables using the complementarity of a fixed platform (HCB, with regular RV visits) and FB. In addition, measurement of associate variables in all platforms, to allow interpretation of carbonate system variability and to test (improve) empirical algorithms providing estimates of carbonate variables (input of Action #5).

Best practices used or developed: Contribution from/to Guidelines for carbonate system data management (T6.3.3.), providing recommendations for Best Practices.

Data flows: (i) Carbonate system associated variables (T, S, meteo, O2, Chl-a) handled, by CMEMS In Situ Thematic Assembly Center (INS TAC), (ii) carbonate system variables will be sent to related databases (e.g. SOCAT) with input from T6.3.3.

Data QC routines: QC procedures for carbonate system associated variables collected from POSEIDON platforms comply with the CMEMS INS TAC. Carbonate variables QC will be defined during the first year.

Data management issues: None expected at this stage.

Expected results: Carbonate system data available via related databases (e.g. SOCAT). Improved understanding of the CO2 solubility and biological pump functioning; creation of reference carbonate system database in the Eastern Med. New collaborative schemes for sustained carbonate system observations.  Results on optimum sampling strategy (maximum number of variables, best platforms, data minimum frequency) (common with action #5).

Users of results: Scientists, ERICs (ICOS), Databases (SOCAT), educators, students, media, Regional Sea Conventions, Ministries, local authorities, UN Sustainable Development goals.

Dissemination of results: During the first year, progress disseminated via tweets and JERICO-S3, POSEIDON websites. The first results are shown in DL4.3. After the first year of data collection communication of the annual cycle results in meetings, related initiatives (e.g ICOS ERIC, SOCAT, EuroGOOS coastal group), and conferences.

Links: To carbonate system actions in other PSS; to ICOS ERIC, SOCAT, MonGOOS (via action #6 and T2.2), the contribution from/to Guidelines for carbonate system data management (T6.3.3), VA of carbonate system data (WP11).