title: Winter and spring controls on the summer food web of the coastal West Antarctic Peninsula.
abstract: Understanding the mechanisms by which climate variability affects multiple trophic levels in food webs is essential for determining ecosystem responses to climate change. Here we use over two decades of data collected by the Palmer Long Term Ecological Research program (PAL-LTER) to determine how large-scale climate and local physical forcing affect phytoplankton, zooplankton and an apex predator along the West Antarctic Peninsula (WAP). We show that positive anomalies in chlorophyll-a (chl-a) at Palmer Station, occurring every 4-6 years, are constrained by physical processes in the preceding winter/spring and a negative phase of the Southern Annular Mode (SAM). Favorable conditions for phytoplankton included increased winter ice extent and duration, reduced spring/summer winds, and increased water column stability via enhanced salinity-driven density gradients. Years of positive chl-a anomalies are associated with the initiation of a robust krill cohort the following summer, which is evident in Adélie penguin diets, thus demonstrating tight trophic coupling. Projected climate change in this region may have a significant, negative impact on phytoplankton biomass, krill recruitment and upper trophic level predators in this coastal Antarctic ecosystem.
authors.affiliation: Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA.
authors.forename: Grace K
authors.initials: GK
authors.lastname: Saba
authors.affiliation: Polar Oceans Research Group, PO Box 368, Sheridan, Montana 59749, USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Fraser
authors.affiliation: National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northeast Fisheries Science Center, c/o Geophysical Fluid Dynamics Laboratory, 201 Forrestal Road, Princeton University Forrestal Campus, Princeton, New Jersey 08540, USA.
authors.forename: Vincent S
authors.initials: VS
authors.lastname: Saba
authors.affiliation: Lamont-Doherty Earth Observatory, PO Box 1000, 61 Route 9W, Palisades, New York 10964, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Iannuzzi
authors.affiliation: Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA.
authors.forename: Kaycee E
authors.initials: KE
authors.lastname: Coleman
authors.affiliation: Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Doney
authors.affiliation: Lamont-Doherty Earth Observatory, PO Box 1000, 61 Route 9W, Palisades, New York 10964, USA.
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Ducklow
authors.affiliation: Lamont-Doherty Earth Observatory, PO Box 1000, 61 Route 9W, Palisades, New York 10964, USA.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Martinson
authors.affiliation: Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA.
authors.forename: Travis N
authors.initials: TN
authors.lastname: Miles
authors.affiliation: Polar Oceans Research Group, PO Box 368, Sheridan, Montana 59749, USA.
authors.forename: Donna L
authors.initials: DL
authors.lastname: Patterson-Fraser
authors.affiliation: 1] Ocean Sciences Department, University of California, 1156 High Street, Santa Cruz, California 95064, USA [2] Institute of Arctic and Alpine Studies, University of Colorado at Boulder, Campus Box 450, Boulder, Colorado 80309, USA.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Stammerjohn
authors.affiliation: Virginia Institute of Marine Science, PO Box 1346, Gloucester Point, Virginia 23062, USA.
authors.forename: Deborah K
authors.initials: DK
authors.lastname: Steinberg
authors.affiliation: Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA.
authors.forename: Oscar M
authors.initials: OM
authors.lastname: Schofield
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D001419:Bacteria; D002734:Chlorophyll / Q000032:analysis; D033201:Euphausiacea; D020387:Food Chain; D010839:Phytoplankton; D012621:Seasons; D046429:Spheniscidae
chemical_list: D002734:Chlorophyll