Physical and Chemical Characteristics of Great Bear Lake, Northwest Territories

Abstract

Great Bear Lake is geologically very young, having been derived from Glacial Lake McConnell 8,000–10,000 yr BP. The lake is made up of two basins with a total volume of 2235.7 km3. This large volume of water and the northern continental climate of the region give rise to a lake that is essentially polar (cold monomictic) although in a northern temperature setting.Chemical composition was extremely uniform; the only observable differences were local and associated with inflowing rivers. In dissolved solids content Great Bear Lake is close to the world’s average for fresh water; it is not typical of waters of the Canadian Shield. Dissolved oxygen was high at all times; it reached a maximum level under the ice in April. The deep water remained fully saturated throughout the year.Comparisons with truly arctic lakes show that Great Bear Lake is similar in many respects but in some aspects it is even more extreme. Although similar in size to Great Slave Lake, it is much more oligotrophic.