TITLE:    Palmer LTER Briefing Book; Palmer Station Site Visit February 1994
AUTHOR:   KS Baker, WR Fraser, EE Hofmann, DM Karl, JM Klinck, RM Ross, LB
          Quetin, BB Prezelin, RC Smith, WZ Trivelpiece
Palmer LTER Contribution #40

The annual advance and retreat of pack ice, a characteristic feature
of polar marine environments, affects about 50% of the Southern Ocean
as well as vast areas of the Arctic Ocean and Bering Sea.  In these
polar environments, pack ice provides marine habitats that are clearly
distinct from those of the open-water (Smith 1987, 1990; Murphy et al.
1988), and where microbial communities abound.  Annual pack ice may
also be the major physical determinant of temporal/spatial changes in
the structure and function of polar biota (Ainley et al. 1986; Fraser
and Ainley 1986; Smith and Vidal 1986; Smith and Nelson 1986; Walsh
and McRoy 1986; Garrison et al. 1987; Ainley et al. 1988; Smith 1990).
Thus, interannual cycles and/or trends in the annual extent of pack
ice are likely to have significant effects on all levels of the food
web, from total annual primary production (Smith et al. 1988) to
breeding success in seabirds (Ainley et al. 1983; Trivelpiece et al.
in press, 1990).