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The importance of winter in annual ecosystem respiration in the High Arctic: effects of snow depth in two vegetation types

Authors

  • Elke Morgner,

    1. Department of Arctic Biology, University Centre in Svalbard, PO Box 156, NO-9171 Longyearbyen, Norway
    2. Department of Arctic and Marine Biology, University of Tromsø, NO-9037 Tromsø, Norway
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  • Bo Elberling,

    1. Department of Arctic Biology, University Centre in Svalbard, PO Box 156, NO-9171 Longyearbyen, Norway
    2. Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K., Denmark
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  • Ditte Strebel,

    1. Department of Arctic Biology, University Centre in Svalbard, PO Box 156, NO-9171 Longyearbyen, Norway
    2. Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K., Denmark
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  • Elisabeth J. Cooper

    Corresponding author
    1. Department of Arctic and Marine Biology, University of Tromsø, NO-9037 Tromsø, Norway
      Elisabeth J. Cooper, Department of Arctic and Marine Biology, University of Tromsø, NO-9037 Tromsø, Norway. E-mail: elisabeth.cooper@uit.no
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Errata

This article is corrected by:

  1. Errata: Corrigendum Volume 29, Issue 3, 474, Article first published online: 22 November 2010

Elisabeth J. Cooper, Department of Arctic and Marine Biology, University of Tromsø, NO-9037 Tromsø, Norway. E-mail: elisabeth.cooper@uit.no

Abstract

Winter respiration in snow-covered ecosystems strongly influences annual carbon cycling, underlining the importance of processes related to the timing and quantity of snow. Fences were used to increase snow depth from 30 to 150 cm, and impacts on respiration were investigated in heath and mesic meadow, two common vegetation types in Svalbard. We manually measured ecosystem respiration from July 2007 to July 2008 at a temporal resolution greater than previously achieved in the High Arctic (campaigns: summer, eight; autumn, six; winter, 17; spring, nine). Moisture contents of unfrozen soil and soil temperatures throughout the year were also recorded. The increased snow depth resulted in significantly higher winter soil temperatures and increased ecosystem respiration. A temperature–efflux model explained most of the variation of observed effluxes: meadows, 94 (controls) and 93% (fences); heaths, 84 and 77%, respectively. Snow fences increased the total non-growing season efflux from 70 to 92 (heaths) and from 68 to 125 g CO2-C m−2 (meadows). The non-growing season contributed to 56 (heaths) and 42% (meadows) of the total annual carbon respired. This proportion increased with deeper snow to 64% in both vegetation types. Summer respiration rates were unaffected by snow fences, but the total growing season respiration was lower behind fences because of the considerably delayed snowmelt. Meadows had higher summer respiration rates than heaths. In addition, non-steady state CO2 effluxes were measured as bursts lasting several days during spring soil thawing, and when ice layers were broken to carry out winter efflux measurements.

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