In the Western Antarctic Peninsula, increased biological activity at many levels of the food web are spatially coherent with submarine canyons. One possible mechanism that links the presence of these canyons to increased biological productivity is through the local upwelling of nutrient-rich modified Upper Circumpolar Deep Water (mUCDW) to the surface, which supports high phytoplankton stocks, krill, penguins, and whales. In the austral summer of 2015, we investigated this hypothesis by deploying three autonomous Slocum gliders over Palmer Deep Canyon, near Palmer Station, Antarctica. Although we observed the shallowing of mUCDW consistent with canyon-driven isopycnal uplift, these deep waters did not penetrate the phytoplankton rich surface mixed layer. Waters below the mixed layer, however, were strongly coherent with bathymetry, suggesting the strong influence of the canyon. The decoupling of the surface mixed layer from the mUCDW suggests that local upwelling may not be the mechanism that supports the biological hotspot. New physical mechanisms that could support the biological hotspot at Palmer Deep Canyon are suggested.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
- West Antarctic Peninsula
- biological hotspot
- canyon hypothesis