Differential Sensitivity to Climate Change of C and N Cycling Processes Across Soil Horizons in a Northern Hardwood Forest

Authors

Jorge Durán, University of CoimbraFollow
Jennifer L. Morse, Portland State UniversityFollow
Alexandra Rodríguez, University of Coimbra
John L. Campbell, USDA Forest ServiceFollow

Published In

Soil Biology and Biochemistry

Document Type

Citation

Publication Date

4-1-2017

Abstract

Climate of the northern hardwood forests of North America will become significantly warmer in the coming decades. Associated increases in soil temperature, decreases in water availability and changes in winter snow pack and soil frost are likely to affect soil carbon (C) and nitrogen (N) cycling. Most studies of the effects of climate change on soil function have focused on the upper-organic part of the soil profile (e.g., forest floor), and little is known about effects on deeper mineral soil horizons. We exploited an elevation/orientation gradient at the Hubbard Brook Experimental Forest (New Hampshire, USA) to evaluate how variation in climate, similar to that projected to occur over the next 50–100 years, affects soil C and N pools and transformation rates in different soil horizons of northern hardwood forests. Lower elevation, south-facing plots with higher soil temperature, less soil moisture and snow, and increased frequency of soil freeze/thaw events had less soil inorganic N content and lower potential net N mineralization rates compared to higher elevation, north facing plots. These differences in N pools and fluxes were consistent for all soil horizons, but sensitivity to climate variation increased with soil depth, confirming that assessments of climate change effects that do not consider variation throughout the soil profile are likely to be incomplete and potentially inaccurate. Nitrogen cycling processes were more sensitive to climate variation than C cycling processes, suggesting a decoupling of C and N cycles in coming decades, with important implications for ecosystem function. Soil processes showed greater sensitivity to climate variation in summer than in spring, and in the warmer and less snowy year of sampling, suggesting that the effects of climate change might become more pronounced as temperatures increase and snow fall and water availability decrease in the coming decades.

Description

additional authors

Locate the Document

http://dx.doi.org/10.1016/j.soilbio.2016.12.028

DOI

10.1016/j.soilbio.2016.12.028

Persistent Identifier

http://archives.pdx.edu/ds/psu/19867

Citation Details

Durán J., Morse J.L., Rodríguez A., Campbell J.L., Christenson L.M., Driscoll C.T., Fahey T.J., Fisk M.C., Mitchell M.J., Templer P.H., Groffman P.M. 2017. Differential sensitivity to climate change of C and N cycling processes across soil horizons in a northern hardwood forest. Soil Biology and Biochemistry 107:77-84.