Carbon fluxes and pelagic ecosystem dynamics near two western Antarctic Peninsula Adelie penguin colonies: an inverse model approach Journal Article


Authors: Sailley, Sevrine F.; Ducklow, Hugh W.; Moeller, Holly V.; Fraser, William R.; Schofield, Oscar M.; Steinberg, Deborah K.; Garzio, Lori M.; Doney, Scott C.
Article Title: Carbon fluxes and pelagic ecosystem dynamics near two western Antarctic Peninsula Adelie penguin colonies: an inverse model approach
Abstract: An inverse food-web model for the western Antarctic Peninsula (WAP) pelagic food web was constrained with data from Palmer Long Term Ecological Research (PAL-LTER) project annual austral summer sampling cruises. Model solutions were generated for 2 regions with Adelie penguin Pygoscelis adeliae colonies presenting different population trends (a northern and a southern colony) for a 12 yr period (1995-2006). Counter to the standard paradigm, comparisons of carbon flow through bacteria, microzooplankton, and krill showed that the diatom-krill-top predator food chain is not the dominant pathway for organic carbon exchanges. The food web is more complex, including significant contributions by microzooplankton and the microbial loop. Using both inverse model results and network indices, it appears that in the northern WAP the food web is dominated by the microbial food web, with a temporal trend toward its increasing importance. The dominant pathway for the southern WAP food web varies from year to year, with no detectable temporal trend toward dominance of microzooplankton versus krill. In addition, sensitivity analyses indicated that the northern colony of Adelie penguins, whose population size has been declining over the past 35 yr, appears to have sufficient krill during summer to sustain its basic metabolic needs and rear chicks, suggesting the importance of other processes in regulating the Adelie population decline.
Keywords: SEA-ICE; FOOD-WEB; climate change; CLIMATE-CHANGE; EUPHAUSIA-SUPERBA; food web; MARGINAL ICE-ZONE; SOUTHERN-OCEAN; Antarctica; AUSTRAL SUMMER; inverse model; KRILL; Microzooplankton; Grazing impact; SPATIOTEMPORAL VARIABILITY; Ecosystem state change; TUNICATE SALPA-THOMPSONI
Journal Title: Marine Ecology Progress Series
Volume: 492
ISSN: 0171-8630
Publisher: Inter Research  
Date Published: 2013
Start Page: 253
End Page: 272
DOI/URL:
Notes: PT: J; TC: 0; UT: WOS:000326439800019