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Title: The origin of soil organic matter controls its composition and bioreactivity across a mesic boreal forest latitudinal gradient

Warmer climates have been associated with reduced bioreactivity of soil organic matter (SOM) typically attributed to increased diagenesis; the combined biological and physiochemical transformation of SOM. In addition, cross–site studies have indicated that ecosystem regime shifts, associated with long–term climate warming, can affect SOM properties through changes in vegetation and plant litter production thereby altering the composition of soil inputs. The relative importance of these two controls, diagenesis and inputs, on SOM properties as ecosystems experience climate warming, however, remains poorly understood. To address this issue we characterized the elemental, chemical (nuclear magnetic resonance spectroscopy and total hydrolysable amino acids analysis), and isotopic composition of plant litter and SOM across a well–constrained mesic boreal forest latitudinal transect in Atlantic Canada. Results across forest sites within each of three climate regions indicated that (1) climate history and diagenesis affect distinct parameters of SOM chemistry, (2) increases in SOM bioreactivity with latitude were associated with elevated proportions of carbohydrates relative to plant waxes and lignin, and (3) despite the common forest type across regions, differences in SOM chemistry by climate region were associated with chemically distinct litter inputs and not different degrees of diagenesis. The observed climate effects on vascular plant littermore » chemistry, however, explained only part of the regional differences in SOM chemistry, most notably the higher protein content of SOM from warmer regions. Greater proportions of lignin and aliphatic compounds and smaller proportions of carbohydrates in warmer sites' soils were explained by the higher proportion of vascular plant relative to moss litter in the warmer relative to cooler forests. Furthermore, these results indicate that climate change induced decreases in the proportion of moss inputs not only impacts SOM chemistry but also increases the resistance of SOM to decomposition, thus significantly altering SOM cycling in these boreal forest soils.« less
Authors:
ORCiD logo [1] ; ORCiD logo [1] ;  [2] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Memorial Univ., St. John's NL (Canada)
  2. Canadian Forest Service, Corner Brook, NL (Canada)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Global Change Biology
Additional Journal Information:
Journal Volume: 24; Journal Issue: 2; Journal ID: ISSN 1354-1013
Publisher:
Wiley
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; bioreactivity; Boreal forest; climate change; moss; nuclear magnetic resonance; Soil organic matter; total hydrolysable amino acids; vegetation
OSTI Identifier:
1474865

Kohl, Lukas, Philben, Michael J., Edwards, Kate A., Podrebarac, Frances A., Warren, Jamie, and Ziegler, Susan E.. The origin of soil organic matter controls its composition and bioreactivity across a mesic boreal forest latitudinal gradient. United States: N. p., Web. doi:10.1111/gcb.13887.
Kohl, Lukas, Philben, Michael J., Edwards, Kate A., Podrebarac, Frances A., Warren, Jamie, & Ziegler, Susan E.. The origin of soil organic matter controls its composition and bioreactivity across a mesic boreal forest latitudinal gradient. United States. doi:10.1111/gcb.13887.
Kohl, Lukas, Philben, Michael J., Edwards, Kate A., Podrebarac, Frances A., Warren, Jamie, and Ziegler, Susan E.. 2017. "The origin of soil organic matter controls its composition and bioreactivity across a mesic boreal forest latitudinal gradient". United States. doi:10.1111/gcb.13887. https://www.osti.gov/servlets/purl/1474865.
@article{osti_1474865,
title = {The origin of soil organic matter controls its composition and bioreactivity across a mesic boreal forest latitudinal gradient},
author = {Kohl, Lukas and Philben, Michael J. and Edwards, Kate A. and Podrebarac, Frances A. and Warren, Jamie and Ziegler, Susan E.},
abstractNote = {Warmer climates have been associated with reduced bioreactivity of soil organic matter (SOM) typically attributed to increased diagenesis; the combined biological and physiochemical transformation of SOM. In addition, cross–site studies have indicated that ecosystem regime shifts, associated with long–term climate warming, can affect SOM properties through changes in vegetation and plant litter production thereby altering the composition of soil inputs. The relative importance of these two controls, diagenesis and inputs, on SOM properties as ecosystems experience climate warming, however, remains poorly understood. To address this issue we characterized the elemental, chemical (nuclear magnetic resonance spectroscopy and total hydrolysable amino acids analysis), and isotopic composition of plant litter and SOM across a well–constrained mesic boreal forest latitudinal transect in Atlantic Canada. Results across forest sites within each of three climate regions indicated that (1) climate history and diagenesis affect distinct parameters of SOM chemistry, (2) increases in SOM bioreactivity with latitude were associated with elevated proportions of carbohydrates relative to plant waxes and lignin, and (3) despite the common forest type across regions, differences in SOM chemistry by climate region were associated with chemically distinct litter inputs and not different degrees of diagenesis. The observed climate effects on vascular plant litter chemistry, however, explained only part of the regional differences in SOM chemistry, most notably the higher protein content of SOM from warmer regions. Greater proportions of lignin and aliphatic compounds and smaller proportions of carbohydrates in warmer sites' soils were explained by the higher proportion of vascular plant relative to moss litter in the warmer relative to cooler forests. Furthermore, these results indicate that climate change induced decreases in the proportion of moss inputs not only impacts SOM chemistry but also increases the resistance of SOM to decomposition, thus significantly altering SOM cycling in these boreal forest soils.},
doi = {10.1111/gcb.13887},
journal = {Global Change Biology},
number = 2,
volume = 24,
place = {United States},
year = {2017},
month = {9}
}