This study provides an improved understanding of the microbial mechanisms contributing to peat decomposition that reduces uncertainty around C cycling in these systems, however, results also suggest the potential for uncoupling of the N and C cycles as these environments evolve over time.
There are large uncertainties about the fate of carbon stored in deep peat deposits under our changing environment. Understanding how microorganisms affect the decomposition of these deposits under varying conditions should help reduce this uncertainty.
Scientists from Oak Ridge National Laboratory hypothesized that the more stable recalcitrant subsurface environment would contain a smaller less diverse microbial enzyme pool, that is better adapted to a narrow temperature range. Potential enzyme activity decreased with peat depth as expected and corresponded with changes in peat composition and microbial biomass. Enzyme activation energy decreased with depth as predicted, however leucine amino peptidase activation energy was much lower than other enzymes, suggesting a limited ability for these N acquiring enzymes to increase activity with increased temperatures. Stable temperatures at depth in the peat appear to result in a microbial community containing enzymes that have lower sensitivity or responsiveness to temperature increases.
Daniel Stover (BER PM)
Christopher W. Schadt (PI)
Senior Staff Scientist, Oak Ridge National Laboratory
Supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research, Terrestrial Ecosystem Science (TES) Program as part of the ORNL SPRUCE project under the TES SFA, and a university led project of The Georgia Institute of Technology (grant number # DE-SC0012088).
Steinweg, J.M., J.E. Kostka, P.J. Hanson and C.W. Schadt, “Temperature sensitivity of extracellular enzymes differs with peat depth but not with season in an ombrotrophic bog.” Soil Biology and Biochemistry 125, 244-250 (2018). [DOI:10.1016/j.soilbio.2018.07.001]
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