Ecology of Sea Ice Biota: Characteristics and Dynamics in Across-Shelf Environmental
Gradients.
Christian H. Fritsen
Desert Research Institute
It is known with reasonable confidence that the structure and dynamics of sea ice biotic
communities differs greatly between land-fast sea ice attached to the continent and the
pack ice that drifts in response to ocean dynamics. Furthermore, there is increasing
evidence (both theoretical and observational) suggesting that differences exist between
biotic communities within pack ice that are influenced by the continental shelf and those
that lie beyond the shelf break (http://www.dri.edu/DEES/Faculty/Fritsen.html, see
Victoria Land Workshop, Figures A and B). However, the distribution and characteristics
of these habitats and communities along this environmental gradient have rarely been
documented. Hence, paradigms regarding the contribution of the Antarctic sea ice
ecosystem to the seasonal production and export cycles of materials of local ecological
and global importance (e.g. Carbon, Nitrogen, Iron, DMS) are not well constrained.
Cruises along the continental shelf and the coastal margins of Antarctica provide an ideal
opportunity to assess the distribution; abundance and activity of sea ice biota among the
aforementioned functionally important sea ice regimes. During the proposed activities
along Victoria Land's coast, experiments and sampling should be designed to compare
the environmental characteristics (e.g. temperature, salinity, light, nutrients) of sea ice
habitats, as well as the microscale (meters to micrometers) distribution and physiology of
the biota within these sea habitats along the continental margin that are linked to the
time-varying dynamics of Circumpolar Deep Water. Such a comparison will allow more
rigorous testing of conceptual (Garrison et al. 1986, Fritsen and Sullivan 1999) and
quantitative models (Fritsen et al. 1998) on the differences between the biota and their
dynamics in these distinct mesoscale ice regimes and how these respond to global
changes at varying time scales.
Fritsen, C.H., J.N. Kremer, S.F. Ackley, and C.W. Sullivan. 1998. Flood-freeze cycles
and algal dynamics in Antarctic pack ice. In M.L. Lizotte and K.R. Arrigo (eds.),
Antarctic Sea Ice: Biological Processes. Antarctic Research Series, American
Geophysical Union. Vol. 73, pp. 1-21.
Fritsen, C. H., and C. W. Sullivan. 1999. Distributions and dynamics of microbial
communities in the pack ice of the western Weddell Sea, Antarctica. In Battaglia, B., J.
Valencia, and D. W. H. Walton, eds. Antarctic Communities: Species, Structure and
Survival. Proc. VI SCOR:SCAR Biology Symposium, London, Cambridge University
Press.
Garrison, D. L., C. W. Sullivan, and S. F. Ackley. 1986. Sea ice microbial communities
in Antarctica. BioScience, 36(4), 243-250.