The Annual Carbon Budget for Fen and Forest in a Wetland at Arctic Treeline

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: Arctic; Hudson; Hudson Bay; Churchill; Subarctic; subarctique*; toundra; Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.511.353; http://www.biometeorology.umn.edu/pdf/arctic_treeline02.pdf

ABSTRACT. Three separate research efforts conducted in the same wetland-peatland system in the northern Hudson Bay Lowland near the town of Churchill, Manitoba, allow a comparison of two carbon budget estimates, one derived from long-term growth rates of organic soil and the other based on shorter-term flux measurements. For a tundra fen and an open subarctic forest, calculations of organic soil accumulation or loss over the last half-century indicate that while the fen on average has lost small amounts of carbon from the ecosystem, the adjacent forest has gained larger amounts of atmospheric carbon dioxide. These longer-term data are supported by shorter-term flux measurements and estimates, which also show carbon loss by the fen and carbon uptake by the forest. The shorter-term data indicate that the fen’s carbon loss is largely attributable to exceptionally dry years, especially if they are warm. The forest may gain carbon at an increased rate as it matures and during warm growing seasons. Also, the changes in relief of the dynamic hummock-hollow landscape in the fen may inhibit photosynthesis. Key words: Subarctic fen and forest, net carbon loss, temperature and water balance variability RÉSUMÉ. Trois travaux de recherche distincts portant sur le même système de marécages/tourbières situés dans la partie septentrionale des basses-terres de la baie d’Hudson, près de la ville de Churchill au Manitoba, permettent de comparer deux estimations du budget de carbone, l’une tirée des taux de croissance à long terme du sol organique et l’autre fondée sur des mesures du flux à plus court terme. Pour une tourbière basse de toundra et une forêt claire subarctique, les calculs de l’accumulation ou de la perte de sol organique au cours des cinquante dernières années révèlent que, si la tourbière basse a perdu en moyenne de petites