Details

Autor(en) / Beteiligte

• Groffman, Peter M
• Hardy, Janet P
• Fashu-Kanu, Samuel
• Driscoll, Charles T
• Cleavitt, Natalie L
• Fahey, Timothy J
• Fisk, Melany C

Titel

Snow depth, soil freezing and nitrogen cycling in a northern hardwood forest landscape

Ist Teil von

• Biogeochemistry, 2011-01, Vol.102 (1-3), p.223-238

Ort / Verlag

Dordrecht: Dordrecht : Springer Netherlands

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Increases in soil freezing associated with decreases in snow cover have been identified as a significant disturbance to nitrogen (N) cycling in northern hardwood forests. We created a range of soil freezing intensity through snow manipulation experiments along an elevation gradient at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains, NH USA in order to improve understanding of the factors regulating freeze effects on nitrate (NO₃ ⁻) leaching, nitrous oxide (N₂O) flux, potential and in situ net N mineralization and nitrification, microbial biomass carbon (C) and N content and respiration, and denitrification. While the snow manipulation treatment produced deep and persistent soil freezing at all sites, effects on hydrologic and gaseous losses of N were less than expected and less than values observed in previous studies at the HBEF. There was no relationship between frost depth, frost heaving and NO₃ ⁻ leaching, and a weak relationship between frost depth and winter N₂O flux. There was a significant positive relationship between dissolved organic carbon (DOC) and NO₃ ⁻ concentrations in treatment plots but not in reference plots, suggesting that the snow manipulation treatment mobilized available C, which may have stimulated retention of N and prevented treatment effects on N losses. While the results support the hypothesis that climate change resulting in less snow and more soil freezing will increase N losses from northern hardwood forests, they also suggest that ecosystem response to soil freezing disturbance is affected by multiple factors that must be reconciled in future research.