British Antarctic Survey,
version 13.9.01 uksoglobec1
In order to achieve an understanding of ecosystems sufficient to predict how they might respond to change, their major interactions need to be identified and examined. To make this objective tractable, GLOBEC has selected “keystone” species for study. Within the Southern Ocean, Antarctic krill (Euphausia superba) is an obvious target species. It has an enormous biomass, which not only supports commercial fisheries and a wide range of other higher predators, but also has impacts on planktonic components of the system. Krill have a broad Southern Ocean distribution, encompassing areas of seasonal sea ice cover and permanently open water regions. Climate driven changes in ocean circulation or winter sea ice will affect the dynamics and distributions of krill populations. Thus it is important to gain a mechanistic understanding of these interactions in order to predict the responses of krill-based food webs to variation and secular change in the environment. SO GLOBEC focuses on the study of key, but poorly known processes dictating krill survival. Such processes include the role of sea ice in their over-wintering success, or their growth and development during dispersal in the Antarctic Circumpolar Current.
Within the Antarctic Circumpolar
Current are oceanic fronts, which may dictate the survival during dispersal of
krill. These fronts are rapid current jets, which can disperse populations far
from their source regions, enhance gene flow across large areas and help
repopulate depleted regions. Some fronts are also zones of enhanced primary
productivity; rich feeding grounds for krill. However, a major question, as yet
unresolved, is the importance of these fronts in providing the phytoplankton
blooms essential for krill survival and reproduction in the ice-free months. A
front of major potential importance to krill is the Southern Antarctic
Circumpolar Current Front (SACCF), as it forms an approximate northern boundary
of their distribution. However, its relationship with the seasonal sea ice zone
and its role in krill dispersal are presently unclear. The proximity of this
front to the
Although krill are a central focus of SO GLOBEC,
it recognises the need for a multidisciplinary approach to understand the
biological and physical processes governing their survival (SO GLOBEC objectives).
The interactions between krill and their food, competitors and predators
dictate growth and mortality. They also dictate behaviour, for example
schooling and diel vertical migration, which in turn
link with the 3D flow field to determine larger scale distribution. As part of
programme, the British Antarctic Survey is conducting a major
interdisciplinary study of the role of oceanic fronts in dictating krill growth
and survival in the
1) How important are oceanic fronts in controlling the growth and development of krill?
2) How important are oceanic fronts in determining the dispersal and survival of krill?
British Antarctic Survey
International Whaling Commission