An autumn bloom of sea-ice algae was observed from February to June of
1992 within the upper 0.4 meter of multiyear ice in the Western Wedde
ll Sea, Antarctica. The bloom was reliant on the freezing of porous ar
eas within the ice that initiated a vertical exchange of nutrient-depl
eted brine with nutrient-rich seawater. This replenishment of nutrient
s to the algal community allowed the net production of 1760 milligrams
of carbon and 200 milligrams of nitrogen per square meter of ice. The
location of this autumn bloom is unlike that of spring blooms previou
sly observed in both polar regions.