title: Winter climate change affects growing-season soil microbial biomass and activity in northern hardwood forests.
abstract: Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots, which accumulated less snow and experienced more soil temperature variability during the winter (and likely more freeze/thaw events), had less extractable inorganic nitrogen (N), lower rates of microbial N production via potential net N mineralization and nitrification, and higher potential microbial respiration during the growing season. Potential nitrate production rates during the growing season were particularly sensitive to changes in winter snow pack accumulation and winter soil temperature variability, especially in spring. Effects of elevation and winter conditions on N transformation rates differed from those on potential microbial respiration, suggesting that N-related processes might respond differently to winter climate change in northern hardwood forests than C-related processes.
authors.affiliation: Cary Institute of Ecosystem Studies, Box AB, 2801 Sharon Turnpike, Millbrook, NY, 12545, USA; Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, 3001-401, Coimbra, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Durán
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Morse
authors.forename: Peter M
authors.initials: PM
authors.lastname: Groffman
authors.forename: John L
authors.initials: JL
authors.lastname: Campbell
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Christenson
authors.forename: Charles T
authors.initials: CT
authors.lastname: Driscoll
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Fahey
authors.forename: Melany C
authors.initials: MC
authors.lastname: Fisk
authors.forename: Myron J
authors.initials: MJ
authors.lastname: Mitchell
authors.forename: Pamela H
authors.initials: PH
authors.lastname: Templer
mesh_terms: D018533:Biomass; D002980:Climate; D057231:Climate Change; D065928:Forests; D009513:New Hampshire; D009584:Nitrogen / Q000378:metabolism; D012621:Seasons; D012914:Snow; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: carbon; global change; microbial respiration; mineralization; nitrification; nitrogen; soil frost