The EuroSea project is progressing as planned: five BGC floats with pH sensors and five Deep floats were deployed in the Atlantic in May and June 2021, respectively. All these floats were tested by the Euro-Argo ERIC team to maximise the chances of successful deployments at sea.
Deployment of five BGC floats with pH sensors
- Framed in the task on “Quality enhancement of tropical carbon fluxes through network optimization of the Tropical Atlantic Observing System” of the EuroSea Climate Demonstrator, the Euro-Argo ERIC procured five BGC Argo floats equipped with dissolved oxygen, pH, chlorophyll-a, downwelling irradiance and backscatter sensors in addition to the CTD head.
- Together with colleagues from SU/LOV, the technical team performed intensive acceptance tests at the Ifremer premises (pool tank of 20 metres deep) to check several float components (hydraulic, communications) as well as sensors behaviour. Water samples were also collected and analysed to measure dissolved oxygen concentration profiles in the pool simultaneous with the floats profiles, enabling to perform a first intercomparison and quality check of the floats data.
- Following the final deployment plan, the 5 floats were deployed in the tropical Atlantic during the the PIRATA-FR31 cruise that took place in March-April 2021.
- The collected data will help developing indicators for carbon flux at the air-sea interface and for ocean acidification based on an improved Atlantic observing system thanks to a neural network (CANYON) and with in situ data collected through fixed stations (PIRATA buoys with pCO2 sensors) and the planned future cruises (PIRATA etc.).
Acceptance tests of the EuroSea BGC floats in February 2021. Left: Water samples collected during the floats ascent profiles, further analysed (Winkler) by Ifremer/LOPS to provide oxygen reference measurements. Right: EuroSea NKE PROVOR CTS4 float with its BGC sensors.
Deployment of five Deep floats
- Framed in the task “Carbon audit of the European relevant deep convection regions” of the EuroSea Climate Demonstrator, the Euro-Argo ERIC procured five Deep Argo floats designed to collect CTD profiles up to depths of 4000 metres.
- In addition to the regular acceptance tests, conducted in the Ifremer pool tank, the technical team performed intensive tests in the hyperbaric chamber at Ifremer premises to ensure the good functioning of the hydraulic system under high pressure.
- These five EuroSea Deep Argo floats were deployed together with another 15 Deep Argo floats from Ifremer (France) on the BOCATS-OVIDE cruise starting in June 2021.
- The collected data will be combined with other data (e.g. from the OVIDE program) and will be used to improve methods to monitor the uptake and storage of carbon in the Irminger Sea and to investigate mechanisms, such as deep convection, involved in the storage and propagation of the carbon signal.
Deep Argo deployment plan of the OVIDE-BOCATS21 cruise (20 floats in total including 5 EuroSea floats). On the top right corner, picture of all the deep floats in a container and prepared for the deployment.