USING SUBARCTIC ATLIN LAKE AS A SPACE-FOR-TIME MODEL FOR DIMINISHING GLACIAL INPUTS TO LARGE MOUNTAIN LAKES

Glacier meltwaters are an important source of nutrients, labile carbon, and cold waters to aquatic organisms in downstream freshwater systems. Atlin Lake is a large (791 km² area) subarctic lake in Yukon and British Columbia, Canada within the Traditional Territories of the Taku River Tlingit (TRTFN) and Carcross/Tagish First Nations (C/TFN). The southern end of Atlin Lake is fed by the Juneau Icefield and other glaciers of the Coast Mountains, while the northern end is glacier-free and fed by streams from forested boreal catchments. Importantly, the outflow occurs mid-lake, separating the southern and northern ends and supporting a natural space-for-time design within a single system that allows us to predict how the southern glacier-fed end of Atlin Lake will change over time. With the glaciers feeding Atlin Lake predicted to be 60% gone by 2100, questions remain about the impact of climate change on the function of Atlin Lake. We comprehensively sampled physical (e.g., temperature, dissolved oxygen, pH), chemical (e.g., nutrients, carbon), and biological (e.g., phytoplankton pigments and speciation, zooplankton speciation and isotopes) parameters, notably from both open-water (i.e., summer) and below-ice (i.e., winter) depth-profiling in the northern (80 m) and southern (270 m) ends of Atlin Lake.  Preliminary pigment results indicate that the northern end of Atlin Lake is nearly twice as productive as the southern end. Therefore, working closely with TRTFN and C/TFN, we seek to answer the critical question of how Atlin Lake  – and other glacier-fed alpine lakes globally – will adapt to climate change.

Presentation Preference: No Preference

Primary Presenter: Jessica Serbu, University of Ottawa (jserbu@uottawa.ca)

Authors:

Jessica Serbu, University of Ottawa  (jserbu@uottawa.ca)

Kyra St. Pierre, University of Ottawa  (kstpier4@uottawa.ca)

Ashley Dubnick, Yukon Research Centre, Yukon University  (adubnick@yukonu.ca)

Hannes Schraft, Taku River Tlingit First Nation Land Guardian Program  (landguardian.coord@gov.trtfn.com)

Isabel Ichiyama, University of Ottawa  (iichi095@uottawa.ca)

Paul Hamilton, Canadian Museum of Nature  (PHAMILTON@nature.ca)