Physical-Biological coupling group
One of the questions addressed by our group is the extent to which abiotic factors shape plankton dynamics as compared to some internal controls or simply to their biological responses. This in turn is assumed to be relevant for biogeochemical processes which, when possible, are analyzed in key sites along the same line with multiple approaches.
To approach the question we try to integrate observational, experimental and numerical approaches, the latter mostly process oriented wise.
More recently we focused on some key forcings on plankton biology, e.g., light variability in the mixed layer and along the circadian cycle, turbulent flow fields and general circulation.
Light is a source of both energy and information for phytoplankton and we try to study both aspects. We conduct numerical studies on virtual phytoplankton whose photobiology is described by state-of-the-art mechanistic models to analyze their responses to variations in light amplitude which mimic the variations occurring in the water column. In parallel we carried out a few experiments to assess the importance of the periodic variation of illumination as due to the circadian cycle on the plankton photophysiology and to investigate to what extent internal regulation may help in coping with it.
Light variability in the numerical studies is generated through numerical simulations of mixing regimes in the water column. Those are in turn produced by a full suite of numerical models (e.g., random walk, kinematic simulations, non hydrostatic models such as the Large Eddy Simulation, the Direct Numerical Simulations etc. fig.1, fig. 2) which also allow for exploring the role played by turbulence in modulating plankton dynamics. Such studies encompass other crucial processes in plankton ecology, e.g., cell sinking and floating, shape impact, encounter rates, nutrient uptake etc.
The insight, as well as the hypotheses, derived by the above investigations are then merged in our observational and modellistic studies which are centered on a time series in the Gulf of Naples (fig.3), in the biogeochemical dynamics of the Mediterranean Sea and the Southern Ocean, whose advances allow to feedback again on the studies at microscale.