Variation in peak growing season net ecosystem production across the Canadian arctic

Peter M. Lafleur, Elyn R. Humphreys, Vincent L. St. Louis, May C. Myklebust, Tim Papakyriakou, Laurier Poissant, Joel D. Barker, Martin Pilote, Kyle A. Swystun

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Tundra ecosystems store vast amounts of soil organic carbon, which may be sensitive to climatic change. Net ecosystem production, NEP, is the net exchange of carbon dioxide (CO2) between landscapes and the atmosphere, and represents the balance between CO2 uptake by photosynthesis and release by decomposition and autotrophic respiration. Here we examine CO 2 exchange across seven sites in the Canadian low and high Arctic during the peak growing season (July) in summer 2008. All sites were net sinks for atmospheric CO2 (NEP ranged from 5 to 67 g C m-2), with low Arctic sites being substantially larger CO2 sinks. The spatial difference in NEP between low and high Arctic sites was determined more by CO2 uptake via gross ecosystem production than by CO2 release via ecosystem respiration. Maximum gross ecosystem production at the low Arctic sites (average 8.6 μmol m-2 s-1) was about 4 times larger than for high Arctic sites (average 2.4 μmol m-2 s-1). NEP decreased with increasing temperature at all low Arctic sites, driven largely by the ecosystem respiration response. No consistent temperature response was found for the high Arctic sites. The results of this study clearly indicate there are large differences in tundra CO2 exchange between high and low Arctic environments and this difference should be a central consideration in studies of Arctic carbon balance and climate change.

Original languageEnglish (US)
Pages (from-to)7971-7977
Number of pages7
JournalEnvironmental Science and Technology
Issue number15
StatePublished - Aug 7 2012
Externally publishedYes

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