Long term changes in a rapidly warming polar pelagic ecosystem

Polar systems have been experiencing accelerating change with increasing wind, melting glaciers and declining sea ice.  These changes are rippling through the WAP ecology and biogeochemistry of the system. The Palmer LTER has for over three decades been tracking how these changes are now rippling through the food web.  Results have shown that the food web is tightly coupled and that changes in the base of the food web rapidly cascades up from a highly productive diatom system through keystone species (Antarctic krill) to penguins and whales.  The food web cascade is a temporally lagged response and appears tightly coupled to the wind and sea ice observed in the winter prior to the austral spring and summer. Over the time series, initially the high inter-annual variability in system responses was driven by competing forcing from cyclical climate forcing (El Nino, Southern Annual Mode, Pacific Decadal Oscillation) overlaid on global anthropogenic changes. While the early variability in the time series appeared to be dominated by the shorter climate forcing, recent observed changes indicate a large-scale shift in the Southern Ocean system. We will focus discussion on assessing the response of the food web in the anomalously warm low sea in the last three years embedded within the longer-term dynamics illuminated within the time series of the Palmer LTER.

Presentation Preference: Either

Primary Presenter: Oscar Schofield, Rutgers University, COOL (oscar@marine.rutgers.edu)

Authors:

Deborah Steinberg, Virginia Institute of Marine Science  (debbies@vims.edu)

Megan Cimino, University of California Santa Cruz, Santa Cruz  (megan.cimino@noaa.gov)

Scott Doney, University of Virginia  (scd5c@virginia.edu)

Ari Friedlaender, University of California Santa Cruz  (ari.friedlaender@ucsc.edu)

Carlos Moffat, University of Delaware  (cmoffat@udel.edu)

Sharon Stammerjohn, University of Colorado, Boulder  (sharon.stammerjohn@colorado.edu)

Benjamin Van Mooy, Woods Hole Oceanographic Institution  (bvanmooy@whoi.edu)