Article ID Journal Published Year Pages File Type
9445218 Applied Soil Ecology 2005 11 Pages PDF
Abstract
This study examines the carbon and nitrogen stocks of soils and vegetation in different frost-boil tundra microsites (rims, troughs and bare soil patches) and aims at elucidating differences in controls of organic matter turnover. Troughs, the wettest microsite, stored the greatest part of soil C and N (23.9 and 1.7 kg m−2, respectively), while drier rims held only 50% and bare soil patches only about 17% of the C and N found in troughs. Both C and N mineralization rates were higher in rims compared to troughs, suggesting a higher turnover of organic matter in rims. On an areal basis N was predominantly mineralized in mineral horizons, while C mineralization was more or less equally distributed between organic and mineral horizons. Thus, atmospheric warming, which has a stronger effect on the upper soil layers, may increase C mineralization to a higher extent than N mineralization (mainly located in lower soil layers). This suggests that frost-boil tundra ecosystems may be (at least in the short-term) sources of CO2 to the atmosphere. Furthermore, the combined results of gross N mineralization and net N mineralization measurements showed a higher microbial sink strength for N in rims compared to troughs, suggesting that decomposition of organic material in rims is controlled mainly by N availability, while the main factor constraining decomposition in troughs may be unfavourable hydrothermal conditions. This may lead to differential responses of frost-boil tundra microsites to changing climatic conditions.
Related Topics
Life Sciences Agricultural and Biological Sciences Ecology, Evolution, Behavior and Systematics
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