An ocean currents observing platform to study the influence of an underwater canyon on coastal ecosystems
GHER and the Laboratory of Biological Oceanography (FOCUS Research Unit) have just obtained a research credit from the F.R.S.-FNRS for the acquisition of nine current meters equipped with multiple sensors that will enable them, in particular, to collect data to help characterize the ecology of the bay and more broadly the dynamics of coastal systems in relation to current climate disturbances.
O
ceans canyons - which can sometimes reach depths of more than 1000 metres - facilitate exchanges between the coastal environment and the ocean through colder, saltier and more nutrient-laden deep water upwelling, or through surface water downwelling that carries nutrients and sediments to the bottom. These flows are very important because they influence the ecology and economy of coastal ecosystems (phytoplankton concentration, presence of fish and marine mammals, fishing activity, etc.). It is therefore important to study these flows in order to understand their dynamics.
The GHER and the Laboratory of Biological Oceanography (FOCUS Research Unit / Faculty of Sciences) have just obtained a research credit from the F.R.S-FNRS to acquire nine current meters, instruments designed to measure the flow rate of water. These new monitoring tools will be implemented in the Bay of Calvi, near STARESO, ULiège's Underwater and Oceanographic Research Station, to study the underwater canyon that borders the bay and its impact on the coastal ecosystem. Six conventional current meters will measure and record the current at the depth at which they are installed and three Acoustic Doppler Current Profilers (ADCP) that, when placed near the bottom, will be able to measure currents in "3D" (velocity profiles in a water thickness). These current meters are also equipped with sensitive sensors capable of measuring salinity, temperature, and dissolved oxygen.
Five anchoring lines will be installed, three at the open bay boundary, one at the canyon boundary and one line inside the bay (Figure 1). This cross-layout will allow water movements to be measured, their directions and velocities to be known.
The data collected will be analyzed and studied by researchers from the ULiège laboratories in order to understand the influence of hydrodynamic processes, such as fronts, eddies and deep water intrusions, on the Bay of Calvi, at different spatial (mesoscale to mesoscale) and temporal (interannual time) scales. These data, combined with meteorological and biological data acquired continuously in the Bay, will make it possible to characterize the Bay (residence time, wind influence, appearance of planktonic blooms, duration of blooms).
The influence and link with large-scale processes, such as the North Atlantic Oscillation (NAO) - a phenomenon affecting the climate system of the northern Atlantic Ocean that causes climate disturbances in the North Atlantic Ocean, Europe and the Mediterranean Sea region - will be investigated by linking it to remote sensing data (infrared and optical sensors).
