The fate of organic sources of carbon in moss-rich tundra soil microbial communities: a laboratory experimental study.
Effects of glucose-carbon supplementation on soil respiration and bacterial and protist biomass were investigated in laboratory studies of three soil samples from Alaskan tundra: spring tussock sample 1 (thin surface moss), spring tussock sample 2 (thick surface moss), and a summer tundra open field sample. Addition of 1% (w/v) glucose solution produced an immediate, pronounced two to three fold increase in respiration above basal rate, which declined over 4 h to baseline levels. Less than 1% (w/w) of glucose-C supplement was respired during the respiratory spike, relative to the 89 μg/g added. A more substantial amount of the glucose-C became incorporated in microbial biomass. The total difference in microbial carbon (μg/g) between the experimental treatments and controls without glucose after 1 wk was as follows: spring sample 1 (8), spring sample 2 (31), and summer sample (70). The percent (w/w) of glucose-C incorporated was: spring sample 1 (5%), spring sample 2 (17%), and summer sample (39%), most attributed to biomass of bacteria and heterotrophic nanoflagellates. Although respiratory response to pulsed glucose-C was minimal, the overall mean basal rate after 1 wk ranged between 4 and 6 nmol/min/g soil, indicating a significant assimilation and respiration of constituent soil organic carbon.
Department of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA. ora@LDEO.Columbia.edu
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Anderson
D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D056890:Eukaryota / Q000145:classification / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D010084:Oxidation-Reduction; D012621:Seasons; D012988:Soil Microbiology
D002244:Carbon; D005947:Glucose