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Interannual variability of the South Georgia marine ecosystem: biological and physical sources of variation in the abundance of krill

Murphy, E. J.; Watkins, J. L.; Reid, K.; Trathan, P. N.; Everson, I.; Croxall, J. P.; Priddle, J.; Brandon, M. A.; Brierley, A. S. and Hofmann, E. (1998). Interannual variability of the South Georgia marine ecosystem: biological and physical sources of variation in the abundance of krill. Fisheries Oceanography, 7(3-4) pp. 381–390.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1046/j.1365-2419.1998.00081.x
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Abstract

Interannual variability is a characteristic feature of the Southern Ocean ecosystem, yet the relative roles of biological and physical processes in generating these fluctuations are unknown. There is now extensive evidence that there are years when there is a very low abundance of Antarctic krill (Euphausia superba) in the South Georgia area, and that this variation affects much of the ecosystem, with the most obvious impacts on survival and breeding success of some of the major predators on krill. The open nature of the South Georgia ecosystem means this variability has large-scale relevance, but even though there are unique time series of data available, information on some key processes is limited. Fluctuations in year-class success in parts, or all, of the krill population across the Scotia Sea can generate large changes in the available biomass. The ocean transport pathways maintain the large-scale ecosystem structure by moving krill over large distances to areas where they are available to predator colonies. This large-scale physical system shows strong spatial and temporal coherence in the patterns of the interannual and subdecadal variability. This physical variability affects both the population dynamics of krill and the transport pathways, emphasizing that both the causes and the consequences of events at South Georgia are part of much larger-scale processes.

Item Type: Journal Article
ISSN: 1054-6006
Keywords: ecosystem; interannual variability; krill; models; Southern Ocean; transport
Academic Unit/Department: Science > Environment, Earth and Ecosystems
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 12094
Depositing User: Mark Brandon
Date Deposited: 20 Oct 2008 11:30
Last Modified: 02 Dec 2010 20:14
URI: http://oro.open.ac.uk/id/eprint/12094
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