Climate and permafrost effects on the chemistry and ecosystems of High Arctic Lakes

Abstract

Permafrost exerts an important control over hydrological processes in Arctic landscapes and lakes. Recent warming and summer precipitation has the potential to alter water availability and quality in this environment through thermal perturbation of near surface permafrost and increased mobility of previously frozen solutes to Arctic freshwaters. We present a unique thirteen-year record (2003–16) of the physiochemical properties of two High Arctic lakes and show that the concentration of major ions, especially SO4 2−, has rapidly increased up to 500% since 2008. This hydrochemical change has occurred synchronously in both lakes and ionic ratio changes in the lakes indicate that the source for the SO4 2− is compositionally similar to terrestrial sources arising from permafrost thaw. Record summer temperatures during this period (2003–16) following over 100 years of warming and summer precipitation in this polar desert environment provide likely mechanisms for this rapid chemical change. An abrupt limnological change is also reflected in the otolith chemistry and improved relative condition of resident Arctic char (Salvelinus alpinus) and increased diatom diversity point to a positive ecosystem response during the same period.

Multiyear variations in High Arctic river temperatures in response to climate variability

“…The presence of Arctic char has been commonly observed in the West River, especially in late season (July, early August, unpublished data S.F. Lamoureux) and are present in both the main downstream lakes and the headwater lake in the West River (Roberts et al 2017). Based on river temperature data from CBAWO, temperatures above 21°C can be considered as an extreme event associated with record warm air temperatures.…”

Geochemistry of Small Canadian Arctic Rivers with Diverse Geological and Hydrological Settings

“…These impacts would be felt in both SFD‐ and LSD‐type systems, though might become more prominent in SFD‐type systems if the retention time of water in the drainage system increases. Deepening of the permafrost active layer could result in increased flushing of Ca (and other constituents) into CAA rivers, as has been observed elsewhere (e.g., Keller et al, ; Lamhonwah et al, ; Roberts et al, ). Our observations within the north and central CAA may already be reflecting this process in SFD rivers, as shown by the “lower” mixing line in Figure .…”

More than just snowmelt: integrated watershed science for changing climate and permafrost at the Cape Bounty Arctic Watershed Observatory

“…The timing of solute increases is strongly suggestive of downstream flushing of solutes from the solute (and especially SO 4 2− ) rich transient layer . Ecosystem effects of these water quality changes are complicated by aquatic amelioration caused by reduced lake ice cover and warmer water, but both diatoms and resident Arctic char show indications of improved aquatic conditions . However, results indicate the importance of integrated hydrological and permafrost research to understand downstream impacts of climate change in High Arctic catchments.…”

“…Both lakes at CBAWO show a sharp increase in water column electrical conductivity (EC) between 2006 and 2016, most notably due to increased SO 4 2–. The increase in lake solute loads appears to be closely associated with the warmest years during the past decade (2011 and 2012) and have resulted in a sharp increase in lake EC and a 500 and 380% increase in SO 4 2− in the West and East Lake from 2006 to 2016, respectively (Figure ). The timing of solute increases is strongly suggestive of downstream flushing of solutes from the solute (and especially SO 4 2− ) rich transient layer .…”