INVESTIGATING TROPHIC AMPLIFICATION AT LONG-TERM MARINE TIME-SERIES SITES

The trophic amplification hypothesis suggests that climate-driven alterations at the base of marine ecosystems (i.e,. phytoplankton) will be amplified by food-web processes.  Thus decreases (or increases) in net primary production will lead to proportionally greater decreases (or increases) in higher trophic levels and fisheries production.  The trophic amplification hypothesis is supported by modeling results and analyses of inter-regional variability in the spatial organization of marine foodwebs.  However, due to a paucity of long-term, multi-trophic level pelagic studies, it has not been thoroughly tested with time series data.  In this project we bring together long-term datasets from the four marine pelagic long-term ecological research (LTER) sites (Palmer LTER in the Western Antarctic Peninsula, California Current Ecosystem LTER, Northeast U.S. Shelf LTER, and Northern Gulf of Alaska LTER), as well as other long-term pelagic time-series to test aspects of the trophic amplification hypothesis.  Specifically, we 1) investigate whether interannual variability increases at higher trophic levels,  2) test whether successive trophic levels are positively correlated and 3) investigate impacts of food web structural variability in ecosystems spanning tropical, temperate and polar seas.  Preliminary results show support for the trophic amplification hypothesis at some, but not all locations. 

Presentation Preference: Oral

Primary Presenter: Michael Stukel, Florida State University (mstukel@fsu.edu)

Authors:

Michael Stukel, Florida State University  (mstukel@fsu.edu)

Alexandra Cabanelas, Woods Hole Oceanographic Institute  (acabanelas@whoi.edu)

John Conroy, University of California, Santa Cruz  (jaconroy@ucsc.edu)

Moira Decima, University of California, San Diego  (mdecima@ucsd.edu)

Beatriz Dias, University of Washington  (biadias@uw.edu)

Gwenn Hennon, University of Alaska  (gmhennon@alaska.edu)

Russell Hopcroft, University of Alaska  (rrhopcroft@alaska.edu)

Thomas Kelly, University of Alaska  (tbkelly@alaska.edu)

Mark Ohman, University of California, San Diego  (mohman@ucsd.edu)

Oscar Schofield, Rutgers University  (oscar@marine.rutgers.edu)

Heidi Sosik, Woods Hole Oceanographic Institute  (hsosik@whoi.edu)

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