Abstract
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic’s largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1 °C relative increase in summer air temperatures. This warming deepened the soil active layer and triggered large mass losses from the watershed’s glaciers, resulting in a ~10 times increase in delivery of glacial meltwaters, sediment, organic carbon and legacy contaminants to Lake Hazen, a >70% decrease in lake water residence time, and near certainty of summer ice-free conditions. Concomitantly, the community assemblage of diatom primary producers in the lake shifted dramatically with declining ice cover, from shoreline benthic to open-water planktonic species, and the physiological condition of the only fish species in the lake, Arctic Char, declined significantly. Collectively, these changes place Lake Hazen in a biogeochemical, limnological and ecological regime unprecedented within the past ~300 years.
Highlights
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic’s largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1 °C relative increase in summer air temperatures
Arctic ecosystems are sensitive to humaninduced climate changes because of how rapidly they are warming due to Arctic amplification[1]
Mean (±SD) summer (June, July, August (JJA)) land surface temperatures of glacier-covered regions of the Lake Hazen watershed increased by 0.21 ± 0.05 °C y−1 from 2000 to 2012, representing a 2.6 °C warming over that time period (Fig. 1)
Summary
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic’s largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1 °C relative increase in summer air temperatures. We demonstrate that the Lake Hazen watershed was not resilient to even an ~1 °C relative increase in recent summer air temperatures. Mean (±SD) summer (June, July, August (JJA)) land surface temperatures of glacier-covered regions of the Lake Hazen watershed increased by 0.21 ± 0.05 °C y−1 from 2000 to 2012, representing a 2.6 °C warming over that time period (Fig. 1).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
