The influence of thermokarst disturbance on the water quality of small upland lakes, Mackenzie Delta region, Northwest Territories, Canada

Chemical data are presented for water from 22 lakes in small upland catchments (< 20 ha) between Inuvik and Richards Island, Northwest Territories, Canada. Eleven of the basins appear pristine and 11 are affected by thermokarst slumping. The mean dissolved organic carbon (DOC) concentration of the pristine lakes (16.3 mg/l) is greater than the mean concentration of lakes disturbed by thermokarst slumping (10.5 mg/l). In pristine lakes, mean concentrations of Ca, Mg and SO4 are 9.6, 3.6 and 11.1 mg/l, but in lakes affected by thermokarst, mean concentrations are 72.6, 26.8 and 208.2 mg/l, respectively. Soluble materials released from degrading permafrost are transported to lakes by surface runoff, elevating concentrations in lake water. The percentage of total basin area influenced by thermokarst is positively associated with ionic concentrations in lake water and inversely related to DOC. Thermokarst occupying as little as 2% of catchment area may modify the chemistry of lake water, and water quality may remain affected for several decades after slump development has ceased. Aerial photographs indicate that 5 to 15% of all lakes and ponds in four 49 km2 areas between Inuvik and Richards Island are small (median size < 2 ha) with catchments affected by thermokarst. Copyright © 2005 John Wiley & Sons, Ltd.

[1]  L. Dyke,et al.  The physical environment of the Mackenzie Valley, Northwest Territories: a base line for the assessment of environmental change , 2000 .

[2]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[3]  W. McDowell,et al.  The effect of permafrost on stream biogeochemistry: A case study of two streams in the Alaskan (U.S.A.) taiga , 1999 .

[4]  Philip Marsh,et al.  A conceptual framework for runoff generation in a permafrost environment , 1999 .

[5]  C. Burn,et al.  Ground ice and soluble cations in near‐surface permafrost, Inuvik, Northwest Territories, Canada , 2003 .

[6]  C. Burn,et al.  Tundra lakes and permafrost, Richards Island, western Arctic coast, Canada , 2002 .

[7]  E. Arnold,et al.  Standard methods for the examination of water and wastewater. 16th ed. , 1985 .

[8]  C. Smith,et al.  Physical and chemical characteristics of the active layer and permafrost, Herschel Island, western Arctic Coast, Canada , 2002 .

[9]  L. Dwyer,et al.  Water quality sourcebook : a guide to water quality parameters , 1979 .

[10]  A. Lewkowicz,et al.  Salinization of Permafrost Terrain Due to Natural Geomorphic Disturbance, Fosheim Peninsula, Ellesmere Island , 1999 .

[11]  L D Dyke.  Stability of permafrost slopes in the Mackenzie valley , 2000 .

[12]  J. Aylsworth,et al.  Landslides of the Mackenzie valley and adjacent mountainous and coastal regions , 2000 .

[13]  John P. Smol,et al.  Physical and chemical limnology of 59 lakes located between the southern Yukon and the Tuktoyaktuk Peninsula, Northwest Territories (Canada) , 1997 .

[14]  C. Burn,et al.  Geochemistry of the active layer and near-surface permafrost, Mackenzie delta region, Northwest Territories, Canada , 2005 .

[15]  G. Czapar,et al.  [Water quality]. , 1992, Verhandelingen - Koninklijke Academie voor Geneeskunde van Belgie.

[16]  M. Dale,et al.  Subarctic forest‐tundra vegetation gradients: The sigmoid wave hypothesis , 1993 .

[17]  J. C. Ritchie,et al.  Past and Present Vegetation of the Far Northwest of Canada. , 1985 .

[18]  A. Lewkowicz,et al.  Slope sediment yield in arid lowland continuous permafrost environments, Canadian Arctic Archipelago , 2002 .

[19]  T.,et al.  Dynamics of Dissolved Organic Carbon in Forested and Disturbed Catchmerits, Westland, New Zealand , 2007 .

[20]  J. R. Mackay.  Pingo ice of the western Arctic coast, Canada , 1985 .

[21]  C. Burn.  Cryostratigraphy, paleogeography, and climate change during the early Holocene warm interval, western Arctic coast, Canada , 1997 .

[22]  Awwa,et al.  Standard Methods for the examination of water and wastewater , 1999 .

[23]  W. Pollard,et al.  A first approximation of the volume of ground ice, Richards Island, Pleistocene Mackenzie delta, Northwest Territories, Canada , 1980 .

[24]  J. R. Mackay.  Active Layer Changes (1968 to 1993) Following the Forest-Tundra Fire near Inuvik, N.W.T., Canada , 1995 .

[25]  S. Carey.  Dissolved organic carbon fluxes in a discontinuous permafrost subarctic alpine catchment , 2003 .

[26]  V. Rampton,et al.  Quaternary geology of the Tuktoyaktuk Coastlands, Northwest Territories , 1988 .

[27]  Philip Marsh,et al.  Processes controlling the rapid drainage of two ice‐rich permafrost‐dammed lakes in NW Canada , 2001 .

[28]  T. Moore,et al.  Dynamics of dissolved organic carbon in forested and disturbed catchments, Westland, New Zealand: 1. Maimai , 1989 .

[29]  R. Bell.  Geological Survey of Canada , 1885, Nature.

[30]  J. R. Mackay,et al.  The Origin of Massive Icy Beds in Permafrost, Western Arctic Coast, Canada , 1971 .

[31]  R. Wein,et al.  Postfire vegetation recovery and tree establishment at the Arctic treeline: climate-change-vegetation-response hypotheses , 1993 .