The ocean comprises the largest dynamic reservoir of carbon in the Earth system, acting as a net sink of about 30% of the total anthropogenic (human-induced) carbon (Cant) emissions, and therefore lowering atmospheric CO2 and limiting climate change. Of the global ocean, the North Atlantic (NA) is one of the major oceans sinks for natural and anthropogenic CO2, and the basin with the highest storage of Cant per area, yet it is still uncertain:
- how much of the Cant uptake occurs locally (i.e., NA subpolar gyre) or remotely (upstream, subtropical gyre),
- or what are the driving mechanisms ultimately regulating the storage of Cant at different temporal scales.
The overarching objective of CARING is to deepen into the role of the Gulf Stream as a driver of the North Atlantic Cant sink variability. The specific objectives are:
* Objective 1) To characterize the Gulf Stream carbon and nutrient contemporary transports.
* Objective 2) To implement fine-scale resolution carbon measurements.
* Objective 3) To compute the magnitude of the downstream carbon and nutrient enrichment rates.
The CARING project comprised a 10-day cruise in July 2022 (FIGURE-CARING cruise, http://dx.doi.org/10.17600/18002940), crossing the Gulf Stream between Bermuda and Cape Hatteras (32-35°N).
PI: Lidia Carracedo
Project partners: Caroline LeBihan (Ifremer, France), Nick Bates (BIOS, Bermuda), Marta Lopez-Mozos (IIM, CSIC, Spain).
FIGURE (Fine scales shaping nitrogen fIxation in the GUlf stREam)
The ocean general circulation plays a critical role in regulating Earth Climate by transporting and sequestrating physical and biogeochemical properties (heat, freshwater, carbon, oxygen) over long spatial and temporal scales. A crucial component of this global circulation is the plunging of surface waters in the North Atlantic taking part in the Meridional Overturning Circulation (MOC), which plays a fundamental role in the physical carbon pump (that is, the physical mechanisms that play a role in the absorption and storage in the ocean of anthropogenic CO2 at different time scales). This is, therefore, a particular area of significant accumulation of anthropogenic CO2 strongly linked to the MOC.
By integrating diverse methodologies and various observation platforms (repeated hydrography, Argo network, gliders, and/or mooring arrays), the main objectives of OCCEAN2s will be:
* Objective 1) To characterise the seasonal cycle of the property transports (main targeted tracers being dissolved inorganic carbon, anthropogenic carbon, oxygen, and inorganic nutrients) across the target basin-scale oceanographic sections.
* Objective 2) To identify the mechanisms affecting the seasonal carbon cycle at the different latitudes considered.
* Objective 3) To compare the patters of variability at the study locations and the implications of these (un)coupled patterns within the domain of study.
PI: Lidia Carracedo
Within the OCCEAN2s project, the PhD student Raphael Bajon will carry out his thesis under the supervision of Herle Mercier (CNRS, France), Lidia Carracedo (Ifremer, France) and Fiz Perez (IIM-CSIC, Spain).
Since 2002, the Ovide project contributes to the observation of both the circulation and the water mass properties along a section from Greenland to Portugal, with additional measurements from Argo float deployments. The main objective of the project is to characterise the interannual variability of:
* The meridional overturning circulation between Greenland and Portugal, the associated main current transports and heat and fresh water transports.
* The water mass properties.
* The inventories and transports of geochemical tracers from natural or anthropogenic origin.
As a project partner, my contribution to the project comprises the cruise participation, and data analysis and exploitation.
BOCATS2 is a continuation of the previous BOCATS project (2014-2017). It is a main contribution to the observation of the NA subpolar gyre by continuing the occupation of the biennial section A25-Ovide (2021 and 2023) within the framework of the international GO-SHIP programme. A particular focus will be given to the new challenge of assessing the variability of the deep circulation in the NA, improving the spatial-temporal resolution of deep currents and water mass characteristics by deploying a regional deep-ARGO array and, at a submilenary scale, using paleoceanographic data obtained in sedimentary records from key sites, such as the Bight and Charlie-Gibbs fracture zones.
As a project partner, my contribution to the project comprises the cruise participation, data analysis and exploitation, and the PhD supervision of Marta Lopez-Mozos.
EuroSea works to improve the European ocean observing and forecasting system in a global context, delivering ocean observations and forecasts to advance scientific knowledge about ocean climate, marine ecosystems and their vulnerability to human impacts and to demonstrate the importance of the ocean to an economically viable and healthy society.
WP7 assesses the ocean role in climate through new ocean climate indicators, and evaluates the economic value of the ocean carbon sink using a combined observing, integration, and dissemination approach. A dedicated task is focusing on carbon fluxes and uptake in the northwest Atlantic (Labrador and Irminger Seas) and the Western Mediterranean, two important areas for carbon uptake. The observations are augmented by Deep-Argo floats from EuroSea to generate user-relevant ocean-climate indicators.
Leaded by Johannes Karstensen, task 7.1 aims to develop information products linking in situ data from autonomous platforms, such as BGC-Argo, moored instrumentation and long-range autonomous surface vehicles (ASVs) deployed in EuroSea, with ocean color data and other observations.
My role within this task links to the linkages between surface physical and biogeochemical constraints and the carbon fluxes. The study will aim at identifying the deep advective routes for anthropogenic carbon in the North Atlantic. It will be carried out by the postdoc Remy Asselot, and supervised by Virginie Thierry and Lidia Carracedo.
Time-series of temperature, salinity and current speeds from the RAPID array at 26°N indicate that the fluxes vary on a range of timescales. ABC Fluxes aimed at addressing the impact of this large variability on the biogeochemical properties by deploying new chemical sensors and samplers on the RAPID mooring array, and by using the new GO-SHIP observations to calculate time-series of nutrient and inorganic carbon fluxes across 26°N.
PI: Elaine McDonagh
To calculate time series (including uncertainty estimates) of inorganic nutrient transport in the Atlantic at 26.5°N using a hierarchy of approaches including new observations.