Nonlinear Processes in Oceanic and Atmospheric Flows


Interplay between hydrodynamic motion and biological activity: Plankton blooms and marine aggregates.

Author: U. Feudel, Institute for Chemistry and Biology of the Marine Environment, Universität Oldenburg.

Names and affiliation of other authors:
Mathias Sandulescu, Jens C. Zahnow, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University, Oldenburg, Germany
Cristóbal López, Emilio Hernández-García, IFISC, CSIC-Universitat de les Illes Ballears, Palma de Mallorca, Spain
Tamás Tél, Institute of Physics, Eötvös University, Budapest, Hungary
Rafael D. Vilela, MPI Physics of Complex Systems, Dresden, Germany

Oral or poster: Oral presentation

Spatio-temporal patterns in marine systems are a result of the interaction of biological and chemical processes with physical transport.
In the water column advection is the dominant physical process. We
study the influence of mesoscale hydrodynamic structures on biological
growth processes in the wake of an island as well as aggregation and
fragmentation of marine aggregates in hydrodynamic flows on small
spatial scales. In both cases we restrict ourselves to two-dimensional
flows and use a stream function approach for the velocity field. In
the case of a horizontal flow in the wake of an island we show how the
upwelling of nutrients away from the island affects the evolution of
plankton close to the island. In particular we show that mesoscale
vortices act as incubators for plankton growth leading to localized
plankton blooms within vortices. In the case of vertical convection
acting on marine aggregates we find that aggregation and fragmentation
lead to a stationary size distribution for marine aggregates which
depends crucially on the type of fragmentation assumed.

*Satellite images from NASA and ESA

Nonlinear Processes in Oceanic and Atmospheric Flows. July 2-4, 2008. Castro Urdiales, Cantabria, Spain.