Top predators in relation to bathymetry, ice and krill during austral winter in Marguerite Bay, Antarctica
Ribic, Christine A.
Fraser, William R.
Lawson, Gareth L.
Wiebe, Peter H.
MetadataShow full item record
A key hypothesis guiding the U.S. Southern Ocean Global Ocean Ecosystems Dynamics (U.S. SO GLOBEC) program is that deep across-shelf troughs facilitate the transport of warm and nutrient-rich waters onto the continental shelf of the Western Antarctic Peninsula, resulting in enhanced winter production and prey availability to top predators. We tested aspects of this hypothesis during austral winter by assessing the distribution of the resident pack-ice top predators in relation to these deep across-shelf troughs and by investigating associations between top predators and their prey. Surveys were conducted July-August 2001 and August-September 2002 in Marguerite Bay, Antarctica, with a focus on the main across-shelf trough in the bay, Marguerite Trough. The common pack-ice seabird species were snow petrel (Pagodroma nivea, 1.2 individuals km-2), Antarctic petrel (Thalassoica antarctica, 0.3 individuals km-2), and Adélie penguin (Pygoscelis adeliae, 0.5 individuals km-2). The most common pack-ice pinniped was crabeater seal (Lobodon carcinophagus). During both winters, snow and Antarctic petrels were associated with low sea ice concentrations independent of Marguerite Trough, while Adélie penguins occurred in association with this trough. Krill concentrations, both shallow and deep, were also associated with Adélie penguin and snow petrel distributions. During both winters, crabeater seal occurrence was associated with deep krill concentrations and with regions of lower chlorophyll concentration. The area of lower chlorophyll concentrations occurred in an area with complex bathymetry close to land and heavy ice concentrations. Complex or unusual bathymetry via its influence on physical and biological processes appears to be one of the keys to understanding how top predators survive during the winter in this Antarctic region.
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 55 (2008): 485-499, doi:10.1016/j.dsr2.2007.11.006.
Showing items related by title, author, creator and subject.
Further analysis of target strength measurements of Antarctic krill at 38 and 120 kHz : comparison with deformed cylinder model and inference of orientation distribution Chu, Dezhang; Foote, Kenneth G.; Stanton, Timothy K. (Acoustical Society of America, 1993-05)Data collected during the krill target strength experiment [J. Acoust. Soc. Am. 87, 16–24 (1990)] are examined in the light of a recent zooplankton scattering model where the elongated animals are modeled as deformed finite ...
Lawson, Gareth L.; Wiebe, Peter H.; Ashjian, Carin J.; Chu, Dezhang; Stanton, Timothy K. (Acoustical Society of America, 2006-01)There are historical discrepancies between empirical observations of Antarctic krill target strength and predictions using theoretical scattering models. These differences are addressed through improved understanding of ...
Effect of orientation on broadband acoustic scattering of Antarctic krill Euphausia superba : implications for inverting zooplankton spectral Martin Traykovski, Linda V.; O'Driscoll, R. L.; McGehee, Duncan E. (Acoustical Society of America, 1998-10)Acoustic scattering experiments involving simultaneous acquisition of broadband echoes and video footage from several Antarctic krill were carried out to determine the effect of animal orientation on echo spectral structure. ...