Project SWARM: The application of an integrated polar ocean observing system to map the physical mechanisms driving food web focusing in an Antarctic biological hotspot.

The physical mechanisms that maintain and deliver phytoplankton and Antarctic krill biomass, potentially increasing prey availability to predators, are not well known. The short surface ocean residence times of 1-2 days over Palmer Deep is in conflict with the prevailing hypotheses that local growth support phytoplankton at the base of the food web in these biological hotspots. Instead, the implication is that horizontal dynamics are likely more important to maintaining these biological hotspots than local upwelling. However, coincident measures of phytoplankton, prey fields, and predator locations in their advective context have not been made to establish the ecological importance of horizontal flow. To better understand these important mechanisms, we are deploying a purpose built integrated polar observatory consisting of high frequency radar, coordinated gliders, small boat surveys, and moorings. This integrated polar observatory will enable us to simultaneously sample across the entire food web from the phytoplankton and prey fields to the top predators to understand the ocean features that support life in these polar systems. For the first time in this region, we will: 1) integrate sensors and technologies to simultaneously map phytoplankton blooms, krill aggregations, and top predator foraging relative to dynamic ocean features; 2) integrate these observations with a high-resolution (1.5 km) 3-D dynamic model simulation of the entire WAP coastal ocean to generalize our field measurements to other known hotspots along the WAP through simulation, and to determine which physical mechanisms lead to the maintenance of these hotspots.