Winter climate change affects growing‐season soil microbial biomass and activity in northern hardwood forests

• Published in: Global change biology 2014-11, Vol.20 (11), p.3568-3577
• Main Authors: Durán, Jorge, Morse, Jennifer L, Groffman, Peter M, Campbell, John L, Christenson, Lynn M, Driscoll, Charles T, Fahey, Timothy J, Fisk, Melany C, Mitchell, Myron J, Templer, Pamela H
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomass; carbon; Climate; Climate Change; Climatology. Bioclimatology. Climate change; Earth, ocean, space; environmental factors; Exact sciences and technology; External geophysics; Forest soils; Forestry; Forests; frost; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; global change; growing season; hardwood forests; Meteorology; microbial biomass; microbial respiration; mineralization; New Hampshire; nitrates; nitrification; nitrogen; Nitrogen - metabolism; Seasons; Snow; snowpack; Soil - chemistry; soil frost; Soil Microbiology; soil temperature; spring; Terrestrial ecosystems; Winter
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.12624

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.