Food resources in the ocean are relatively diffuse, and need to be concentrated for  consumers. This is done, in part by mesoscale and sub mesoscale oceanographic features transporting and locally concentrating plankton, creating patchy regions of high prey availability. Lagrangian approaches applied to coastal ocean dynamics can identify the transport features responsible for plankton patchiness, linking highly nonlinear coastal flow to the spatial ecology of food webs. This study employs two Lagrangian coherent structure approaches, Finite Time Lyapunov Exponents (FTLE) and Relative Particle Density (RPD), to coastal surface currents observed by High Frequency Radars (HFR) around a known biological hotspot, Palmer Deep Antarctica. FTLE and RPD results were compared to the spatial ecology of phytoplankton, zooplankton, and foraging penguins, relating each level of the food web to lagrangian transport. Simultaneous measurements of the physics and food web were gathered through the integration of vessel and autonomous glider surveys within the HFR footprint. Results show FTLE better define borders of plankton patches while RPD better define centers of plankton patches that are then targeted by penguins. Transport features quantified by FTLE and RPD deliver and concentrate constant supplies of plankton, maintaining prey resources. Results will inform future work in the identification of biophysical interactions in more complex food webs, and expand the use of HFR data to track spatial ecology.

Primary Presenter: Jacquelyn Veatch, Rutgers University (jveatch@marine.rutgers.edu)

Authors:

Jacquelyn Veatch, Rutgers University  (jveatch@marine.rutgers.edu)

Josh Kohut, Rutgers University  (kohut@marine.rutgers.edu)

Erick Fredj, Jerusalem College of Technology  (erick.fredj@gmail.com)

Matthew Oliver, University of Delaware  (moliver@udel.edu)