Some characteristics of the data
The data presented are the taxonomic compositions of diatom assemblages expressed in relative frequencies and, in the case of Solstice Lake, their absolute abundance per gram of dried sediment. The primary months reflected by the diatom data are the latter part of July, August, and the first half of September. This period represents the time of open water, and hence of main diatom production. However, it is noted that the duration of ice-free conditions is conditioned by winter and spring conditions, and that many diatoms are adapted to low-light conditions and may therefore grow beneath even thick ice cover.