Limnological evolution of Zelma Lake, a recently drained thermokarst lake in Old Crow Flats (Yukon, Canada)

Arctic Science

article

Jana M.E. Tondu¹  Kevin W. Turner²  Johan A. Wiklund¹  Brent B. Wolfe³  Roland I. Hall¹  Ian McDonald⁴ 

[1] Department of Biology, University of Waterloo;Department of Geography, Brock University;Department of Geography and Environmental Studies, Wilfrid Laurier University;Yukon Field Unit

关键词: climate change;    thermokarst lakes;    paleolimnology;    limnology;    lake drainage.;   

DOI  :  10.1139/as-2016-0012

学科分类：地球科学(综合)

来源: NRC Research Press

【 摘 要 】

Evidence from remote sensing studies suggests that the frequency of thermokarst lake drainage events is increasing in response to climate change, but the consequences of these changes on the limnology of remaining waterbodies remain unknown. Here, we utilize a multiparameter paleolimnological record and post-drainage water isotope and chemistry monitoring to characterize the limnological evolution of Zelma Lake in Old Crow Flats, Yukon. During the early part of the record (~1678 to 1900 CE), analysis of geochemical variables and algal pigments indicate relatively stable limnological conditions. Abruptly beginning at ~1900, Zelma Lake experienced a 40 year phase of reduced production, likely resulting from thermokarst shoreline expansion and associated increases in turbidity and low light availability. This was followed by ~70 years of increasing production, likely from the stabilization of shorelines combined with a warming climate. Zelma Lake catastrophically drained in June 2007. Post-drainage conditions were characterized by intense eutrophication marked by increases in nutrient and major ion concentrations and the unprecedented occurrence of okenone and diatoxanthin pigments. Comparison to the post-drainage paleolimnological record from another thermokarst lake in Old Crow Flats indicates that a sharp increase of production is likely a common outcome of thermokarst lake drainage, yet intensity differs owing to site-specific catchment characteristics.

【 授权许可】

CC BY