A model of soil organic matter quality under anaerobic conditions in Arctic and subarctic soils

Abstract

The extent of anaerobic respiration by soil microbes is dependent on many factors, including water and nutrient availability, pH, temperature, oxidation/reduction potential, and soil organic matter quality. An understanding of the influence of these factors on anaerobic respiration is important as carbon dioxide (CO₂) and methane (CH₄) can act as greenhouse gasses. This study investigated the relationship between soil organic matter (SOM) and anaerobic respiration potential in arctic and sub-arctic soils. A model was developed to describe the dependence of anaerobic gas production on SOM properties. The model was generated by correlating SOM properties to anaerobic gas production for a suite of soils collected from the U.S., Canadian, and Scandinavian Arctic and Subartic. The SOM properties were characterized using pyrolysis-gas chromatography/mass spectrometry. The anaerobic gas production was measured using laboratory incubations. This model was then applied to soil samples taken from the Smith Lake Methane Flux Site at the University of Alaska Fairbanks in order to predict the anaerobic respiration gas production potential from soils in this area. Maps were constructed showing the predicted amount of anaerobic respiration within a 0.75 mile radius of the Smith Lake Methane Flux Site.