Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest
Climate change is expected to alter the mechanisms controlling soil organic matter (SOM) stabilization. Under climate change, soil warming and drying could affect the enzymatic mechanisms that control SOM turnover and dependence on substrate concentration. Here, we used a greenhouse climate manipula...
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ftcdlib:oai:escholarship.org/ark:/13030/qt0tb4j1b9 2023-05-15T17:58:10+02:00 Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest German, DP Allison, SD 525 - 533 2015-07-10 application/pdf https://escholarship.org/uc/item/0tb4j1b9 unknown eScholarship, University of California qt0tb4j1b9 https://escholarship.org/uc/item/0tb4j1b9 public Biology and Fertility of Soils, vol 51, iss 5 Microbial decomposition Starch Cellulose Carbon cycling Carbon dioxide Extracellular enzymes Agronomy & Agriculture Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences article 2015 ftcdlib 2021-04-16T07:10:18Z Climate change is expected to alter the mechanisms controlling soil organic matter (SOM) stabilization. Under climate change, soil warming and drying could affect the enzymatic mechanisms that control SOM turnover and dependence on substrate concentration. Here, we used a greenhouse climate manipulation in a mature boreal forest soil to test two specific hypotheses: (1) Rates of decomposition decline at lower substrate concentrations, and (2) reductions in soil moisture disproportionately constrain the degradation of low-concentration substrates. Using constructed soil cores, we measured decomposition rates of two polymeric substrates, starch and cellulose, as well as enzyme activities associated with degradation of these substrates. The greenhouse manipulation increased temperature by 0.8°C and reduced moisture in the constructed cores by up to 90%. We rejected our first hypothesis, as the rate of starch decomposition did not decrease with declining starch concentration under control conditions, but we did find support for hypothesis two: Drying led to lower decomposition rates for low-concentration starch. We observed a threefold reduction in soil respiration rates in bulk soils in the greenhouses over a 4-month period, but the C losses from the constructed cores did not vary among our treatments. Activities of enzymes that degrade cellulose and starch were elevated in the greenhouse treatments, which may have compensated for moisture constraints on the degradation of the common substrate (i.e., cellulose) in our constructed cores. This study confirms that substrate decomposition can be concentration-dependent and suggests that climate change effects on soil moisture could reduce rates of decomposition in well-drained boreal forest soils lacking permafrost. Article in Journal/Newspaper permafrost University of California: eScholarship |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Microbial decomposition Starch Cellulose Carbon cycling Carbon dioxide Extracellular enzymes Agronomy & Agriculture Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences |
spellingShingle |
Microbial decomposition Starch Cellulose Carbon cycling Carbon dioxide Extracellular enzymes Agronomy & Agriculture Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences German, DP Allison, SD Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
topic_facet |
Microbial decomposition Starch Cellulose Carbon cycling Carbon dioxide Extracellular enzymes Agronomy & Agriculture Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences |
description |
Climate change is expected to alter the mechanisms controlling soil organic matter (SOM) stabilization. Under climate change, soil warming and drying could affect the enzymatic mechanisms that control SOM turnover and dependence on substrate concentration. Here, we used a greenhouse climate manipulation in a mature boreal forest soil to test two specific hypotheses: (1) Rates of decomposition decline at lower substrate concentrations, and (2) reductions in soil moisture disproportionately constrain the degradation of low-concentration substrates. Using constructed soil cores, we measured decomposition rates of two polymeric substrates, starch and cellulose, as well as enzyme activities associated with degradation of these substrates. The greenhouse manipulation increased temperature by 0.8°C and reduced moisture in the constructed cores by up to 90%. We rejected our first hypothesis, as the rate of starch decomposition did not decrease with declining starch concentration under control conditions, but we did find support for hypothesis two: Drying led to lower decomposition rates for low-concentration starch. We observed a threefold reduction in soil respiration rates in bulk soils in the greenhouses over a 4-month period, but the C losses from the constructed cores did not vary among our treatments. Activities of enzymes that degrade cellulose and starch were elevated in the greenhouse treatments, which may have compensated for moisture constraints on the degradation of the common substrate (i.e., cellulose) in our constructed cores. This study confirms that substrate decomposition can be concentration-dependent and suggests that climate change effects on soil moisture could reduce rates of decomposition in well-drained boreal forest soils lacking permafrost. |
format |
Article in Journal/Newspaper |
author |
German, DP Allison, SD |
author_facet |
German, DP Allison, SD |
author_sort |
German, DP |
title |
Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
title_short |
Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
title_full |
Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
title_fullStr |
Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
title_full_unstemmed |
Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest |
title_sort |
drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted inceptisols from a boreal forest |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/0tb4j1b9 |
op_coverage |
525 - 533 |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Biology and Fertility of Soils, vol 51, iss 5 |
op_relation |
qt0tb4j1b9 https://escholarship.org/uc/item/0tb4j1b9 |
op_rights |
public |
_version_ |
1766166708220854272 |