Population distribution of krill are subject to current advection, but also sea ice – a key overwintering habitat providing food and refuge from predators. Sea ice, however, drifts due to the combined product of currents, wind and internal stress, and to date has not been explicitly included into population dispersal modeling studies. In an experiment focusing on the Southern Ocean between 40oS and 78oS, Thorpe and colleagues drive a Lagrangian particle tracking scheme using ocean current velocity output at resolution ¼ by ¼ degree from OCCAM model and sea ice vectors obtained using the Polar Pathfinder satellite. The experiments shows that the inclusion of sea ice as a factor into krill dispersal, identifies new source regions for the South Georgia krill populations.
Depending on the locality as well as krill life cycle stage, sea ice acts as either a retention or dispersal mechanism and can generate alternate directions of drift. These interactions will be particularly important in the high krill density regions of the Antarctic Peninsula, Scotia Sea and spawning areas.
S.E. Thorpe, E.J. Murphy* and J.L. Watkins, 2007. Circumpolar connections between Antarctic krill (Euphausia superba Dana) populations: Investigating the roles of ocean and sea ice transport. Deep Sea Research Part I: Oceanographic Research Papers, In Press, Accepted Manuscript (doi:10.1016/j.dsr.2007.01.008 )
- Summary of trophic level 2 models – (provided by the Model Shopping Tool)
- Southern Ocean System - Calanus finmarchicus Life Cycle model equations (provided by the Model Shopping Tool)