Publication Date:
2022-05-26
Description:
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Progress in Oceanography 122 (2014): 10-29, doi:10.1016/j.pocean.2013.11.007.
Description:
The productivity and linkages in the food web of the southern region of the west Antarctic
Peninsula continental shelf were investigated using a multi-trophic level mass balance model.
Data collected during the Southern Ocean Global Ocean Ecosystem Dynamics field program
were combined with data from the literature on the abundance and diet composition of
zooplankton, fish, seabirds and marine mammals to calculate energy flows in the food web
and to infer the overall food web structure at the annual level. Sensitivity analyses
investigated the effects of variability in growth and biomass of Antarctic krill (Euphausia
superba) and in the biomass of Antarctic krill predators on the structure and energy fluxes in
the food web. Scenario simulations provided insights into the potential responses of the food
web to a reduced contribution of large phytoplankton (diatom) production to total primary
production, and to reduced consumption of primary production by Antarctic krill and
mesozooplankton coincident with increased consumption by microzooplankton and salps.
Model-derived estimates of primary production were 187 – 207 g C m-2 y-1, which are
consistent with observed values (47-351 g C m-2 y-1). Simulations showed that Antarctic krill
provide the majority of energy needed to sustain seabird and marine mammal production,
thereby exerting a bottom-up control on higher trophic level predators. Energy transfer to top
predators via mesozooplanton was a less efficient pathway, and salps were a production loss
pathway because little of the primary production they consumed was passed to higher trophic
levels. Increased predominance of small phytoplankton (nanoflagellates and cryptophytes)
reduced the production of Antarctic krill and of its predators, including seabirds and seals.
Description:
Support for T. Ballerini and E. Hofmann was provided by NSF grant OCE-0814584, for D.
Ainley by ANT-0944411 and OCE-0814406, for C. Ribic by OCE-0814406. K. Daly and M.
Marrari were supported by NSF grant OCE-0814405.
Keywords:
Antarctic krill
;
Climate change
;
Donor-controlled model
;
Food web
;
Mass balance model
;
Southern Ocean
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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