Releases of the greenhouse gases carbon dioxide (CO2) and methane (CH4) from thawing permafrost are expected to be among the largest feedbacks to climate from arctic ecosystems. However, the current net carbon (C) balance of terrestrial arctic ecosystems is unknown. Recent studies suggest that these ecosystems are sources, sinks, or approximately in balance at present…. More

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Some studies have reported that spring warming and earlier snowmelt leads to increased CO2sequestration in Arctic terrestrial ecosystems. We measured tundra-atmosphere CO2 exchange via eddy covariance at two low Arctic sites (mixed upland tundra and sedge fen) in central Canada over multiple snow-free periods to assess this hypothesis. Both sites were net sinks for atmospheric… More

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Tundra-atmosphere exchanges of carbon dioxide (CO2) and water vapour were measured near Daring Lake, Northwest Territories in the Canadian Low Arctic for 3 years, 2004–2006. The measurement period spanned late-winter until the end of the growing period. Mean temperatures during the measurement period varied from about 2 °C less than historical average in 2004 and… More

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