Physical-Planktonic Interactions on the Brazil Current Eddies off Southeast Brazil

Abstract

The Brazil Current (BC) flows along the Southeastern Brazil continental margin. Between 20°S and 23°S, the coastline changes direction. Therefore, BC becomes unstable which leads to the formation of large cyclonic meanders, specially off Cape Frio. This region is also characterized by coastal up\-welling during most of the year. The interaction between up\-welling-favorable winds and BC's cyclonic meanders makes this area highly biologically productive. There are no studies about planktonic dynamics associated with these mesoscale vortical features. Thus, this work aims to examine the variation in the Nutrients-Phytoplankton-Zooplankton dynamics (NPZ) on a dettaching idealized cyclonic eddy. We will employ the quasi-geostrophic theoretical framework on semi-analytical models with discrete potential vorticity structure, to be computed by the Contour Dynamics Method, or continuous potential vorticity configuration, to be solved on a traditional finite difference grid. The dynamical model consists of a meridional jet flowing southward with a rigid western boundary. This suite of hydrodynamic modeld will be coupled to a variety of NPZ biological configurations, as presented by Franks (2002).