Comparing bioavailability in five Arctic soils by pyrolysis-gas chromatography/mass spectrometry

Abstract

The bioavailability of soil organic matter (SOM) from five Arctic soils was studied using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and laboratory incubation techniques. Soil samples were incubated concurrently at 4 and 25 °C for approx. 4 months. Py-GC/MS was used to determine the relative percentage of a suite of chemical components in the SOM before and after incubation at both temperatures. Following incubation at 4 °C, the relative percentage of polysaccharides and phenols in SOM decreased compared to that of amino carbohydrates and lipids. The change in the relative percentage of lignin was uncorrelated to any other fraction of the soil organic matter. Following incubation at 25 °C, the relative percentage of polysaccharides and lignin in SOM decreased compared to that of lipids. The changes in relative percentage of amino carbohydrates and phenols were uncorrelated to any other fraction of the SOM. The cumulative mass of carbon dioxide respired during incubation was found to be strongly correlated to the initial relative abundance of polysaccharides for incubations at 4 °C.