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In the past decades, both modelling and theoretical studies have identified the fine scale (small eddies, current filaments of the order of 10 km) as a dynamical regime with large consequences for planktonic ecosystems. Modellers also generally highlight the need for in situ measurements at the fine scales. Nevertheless, this represents a big challenge due to the ephemeral nature of fine scale structures. Moreover, in order to study physical-biological coupling at the fine scale it is crucial to perform biological measurements at high frequency.
The FUMSECK (Facilities for Updating the Mediterranean Submesoscale - Ecosystem Coupling Knowledge, chief scientist S. Barrillon, MIO) cruise is a one-week technological cruise, from April, 30, 2019 to May, 05, 2019, in the Genoa gulf in the Mediterranean Sea, onboard the R/V Téthys II. It aims at performing several technological tests of some instruments used for the study of the fine scale processes and dynamics (from 0.1 to 100 km for a lifetime from several days to several weeks). | |
| The first test category is the study of the MVP (Moving Vessel Profiler) tracked instruments behaviour: SSFFF (Single Sensor Free Fall Fish, so called "small fish”) and MSFFFII (Multi Sensor Free Fall Fish, so called "small fish”). In particular, we will focus on the rotative behaviour of the big fish during its falling and raising, the connectics between the instrument and the MVP cable, between the platform and the boat depth sensor, and between the platform and the PC used to analyze the data, hence testing the whole data acquisition chain. Secondly, we will experiment the release of a sample of biodegradable fluorescent micro-particles in order to study their dispersion and detectability using cytometry. This study will include a test of the pumping system for the water going into the cytometer. The last category concerns the exploration of several methods to access the measurement of the current velocities vertical component, using different ADCP (Hull-mounted ADCP, Fixed-depth or profiling L-ADCP, Free-Fall ADCP, and Sentinel), a prototype of a vertical velocity profiler, and a glider. This work is part of the project BioSWOT funded by the CNES (PI F.d'Ovidio, LOCEAN-IPSL, co-PIs A.M.Doglioli and G.Grégori, MIO), that aims at paving the way to the scientific exploitation of the future satellite SWOT (Surface Water and Ocean Topography, https://swot.cnes.fr/ ) observations beyond physical oceanography, focusing in particular on current biophysical questions. Besides guaranteeing an optimal exploitation of SWOT data from the beginning of its mission by a large interdisciplinary community, this preparatory activity will be critical for not missing opportunities of interdisciplinary in situ experiments during the SWOT mission, in particular for the fast sampling phase, in which high temporal resolution will also be provided. |  Geographical zone and stations of the FUMSECK cruise. Trajectory example in the presence of an eddy. |
| This work is part of the project BioSWOT funded by the CNES (PI F.d'Ovidio, LOCEAN-IPSL, co-PIs A.M.Doglioli and G.Grégori, MIO), that aims at paving the way to the scientific exploitation of the future satellite SWOT (Surface Water and Ocean Topography, https://swot.cnes.fr/ ) observations beyond physical oceanography, focusing in particular on current biophysical questions. Besides guaranteeing an optimal exploitation of SWOT data from the beginning of its mission by a large interdisciplinary community, this preparatory activity will be critical for not missing opportunities of interdisciplinary in situ experiments during the SWOT mission, in particular for the fast sampling phase, in which high temporal resolution will also be provided. | |
| The BioSWOT project from CNES develops a collaboration between the MIO (Mediterranean Institute of Oceanography), the SHOM (Service Hydrographique et Océanographique de la Marine) and the IMEDEA and SOCIB. A.Doglioli et G.Grégori have been onboard the BHO Beautemps Beaupré for the PROTEVS*-SWOT** cruise (PI F.Dumas) in the Occidental Mediterranean Sea, South of the Baleares Islands from April 28th to May 16th. | In close interaction with a team on land (A.Petrenko, S.Barrillon, L.Rousselet, M.Thyssen) and in contact with colleagues from the IMEDEA and SOCIB (PI A.Pascuale et J.Allen) onboard the r.v. "Garcia del Cid" , the researchers from MIO are interested in the role played by the currents on the structure and dynamics of the phytoplankton. |
| These microorganisms play a major role as they are at the basis of the trophic network, are involved in the cycle of the biogenic elements, and fuel the Ocean in dissolved O2 thanks to the process of primary production. An automated flow cytometer Cytosense (Cytobuoy) has been implemented onboard to study the phytoplanktonic cells at the single cell level and at high frequency (every half an hour). The cytometer has been implemented on the water supply from the TSG of the ship. |
The Cytosense flow cytometer measures light scatter and fluorescence properties of the particles in suspension in the sea water. Based on these properties, similar cells form flow cytometry groups. The flow cytometry data are used to detect, count, follow the dynamics and distribution of the cells along the ship track. Some pictures can also be taken to identify the cells. The data collected during the cruise already give a glimpse of the biodiversity of the sea surface currents at the surface of the Ocean. During the cruise, more than 15 million cells have been analyzed. The physical and biological data collected so far will provide valuable results that will be used for the exploitation of the future satellite SWOT. * PROTEVS : Prévision Océanique, Turbidité, Ecoulement, Vagues et Sédimentologie ** SWOT : Surface Water and Ocean Topography |