The most familiar icy environments, seasonal lake and stream
ice, have received little microbiological study. Bacteria and Eukarya dominated the microbial assemblage within the seasonal
ice of Miquelon Lake, a shallow saline lake in Alberta, Canada. The bacterial assemblages were moderately diverse and did not vary with either
ice depth or time. The closest relatives of the bacterial sequences from the
ice included Actinobacteria, Bacteroidetes, Proteobacteria, Verrucomicrobia, and Cyanobacteria. The eukaryotic assemblages were less conserved and had very low diversity. Green algae relatives dominated the eukaryotic gene sequences; however, a copepod and cercozoan were also identified, possibly indicating the presence of complete microbial loop. The persistence of a
chlorophyll a peak at 25-30 cm below the
ice surface, despite
ice migration and
brine flushing, indicated possible
biological activity within the
ice. This is the first study of the composition, diversity, and stability of seasonal lake
ice.