Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Characterizing soil organic matter quality in arctic soil by cover type and depth
AbstractIn the past 30 years, the arctic climate has warmed appreciably. Mounting evidence suggests that climate warming is being amplified at the earth's polar regions. A warmer Arctic could lead to the gradual loss of circumpolar permafrost. Northern soils are estimated to contain 25–33% of the world's soil carbon, much of which is frozen in permafrost as poorly decomposed plant remains. A warming and thawing of northern permafrost would result in an increase in soil organic matter (SOM) exposed to decomposition. Carbon dioxide (CO2) or methane (CH4) released from decomposing SOM would likely result in a positive feedback to climate warming. The rate that SOM decomposes in soil depends on many variables, including temperature, soil moisture, nutrient availability, pH, oxidation–reduction potential, and chemical composition of the SOM. This paper addresses the effect of regional scale ecosystem differences on SOM composition and the potential for CO2 to be respired from these soils under SOM-limiting conditions. In previous research, an empirical model was developed to predict CO2 flux from arctic soils based on specific compounds in the SOM. The model was built using an incubation designed to create SOM-limiting conditions and pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) analysis of SOM. SOM-limiting conditions were defined as the state in which microbial respiration was limited only by the SOM quality. That is, during the incubation, ample nutrients were available to microorganisms, the pH was neutral, and the system was kept aerobic, mixed, and at 20 °C. SOM that was rapidly mineralized was defined as being of high quality. SOM that was slowly mineralized was defined as being of low quality. With an understanding of SOM quality in different soil types, one can better understand the relative potential for different soils to contribute to atmospheric CO2 in a warmer, drier arctic environment. In the research described herein, soils from across the Western and Northern Alaska transects were analyzed to determine if SOM quality could be tied to cover class, a parameter that can be remotely sensed. In nearly all cases, SOM quality under similar cover classes was of similar quality regardless of its geographic origin. The clearest trend observed was that SOM quality was highest in soil under moist acidic tundra, followed by tussock tundra and tundra/shrub transitions, shrubs, and nonacidic tundra, respectively.
Characterizing soil organic matter quality in arctic soil by cover type and depth
AbstractIn the past 30 years, the arctic climate has warmed appreciably. Mounting evidence suggests that climate warming is being amplified at the earth's polar regions. A warmer Arctic could lead to the gradual loss of circumpolar permafrost. Northern soils are estimated to contain 25–33% of the world's soil carbon, much of which is frozen in permafrost as poorly decomposed plant remains. A warming and thawing of northern permafrost would result in an increase in soil organic matter (SOM) exposed to decomposition. Carbon dioxide (CO2) or methane (CH4) released from decomposing SOM would likely result in a positive feedback to climate warming. The rate that SOM decomposes in soil depends on many variables, including temperature, soil moisture, nutrient availability, pH, oxidation–reduction potential, and chemical composition of the SOM. This paper addresses the effect of regional scale ecosystem differences on SOM composition and the potential for CO2 to be respired from these soils under SOM-limiting conditions. In previous research, an empirical model was developed to predict CO2 flux from arctic soils based on specific compounds in the SOM. The model was built using an incubation designed to create SOM-limiting conditions and pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) analysis of SOM. SOM-limiting conditions were defined as the state in which microbial respiration was limited only by the SOM quality. That is, during the incubation, ample nutrients were available to microorganisms, the pH was neutral, and the system was kept aerobic, mixed, and at 20 °C. SOM that was rapidly mineralized was defined as being of high quality. SOM that was slowly mineralized was defined as being of low quality. With an understanding of SOM quality in different soil types, one can better understand the relative potential for different soils to contribute to atmospheric CO2 in a warmer, drier arctic environment. In the research described herein, soils from across the Western and Northern Alaska transects were analyzed to determine if SOM quality could be tied to cover class, a parameter that can be remotely sensed. In nearly all cases, SOM quality under similar cover classes was of similar quality regardless of its geographic origin. The clearest trend observed was that SOM quality was highest in soil under moist acidic tundra, followed by tussock tundra and tundra/shrub transitions, shrubs, and nonacidic tundra, respectively.
Characterizing soil organic matter quality in arctic soil by cover type and depth
White, Daniel M. (Autor:in) / Garland, D.Sarah (Autor:in) / Ping, Chien-Lu (Autor:in) / Michaelson, Gary (Autor:in)
Cold Regions, Science and Technology ; 38 ; 63-73
07.08.2003
11 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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