Lipson Lab HOME

Current and Recent Research Projects 

Colorado Rocky Mountains

Soil Respiration and Microbial Diversity in a Subalpine Forest

The Lipson laboratory is currently studying the importance of soil microbial community composition in determining ecosystem respiration, particularly under winter snow packs.  Our study site is a subalpine forest, dominated by Abies lasiocarpa (subalpine fir), Pinus contorta (lodgepole pine), and Picea engelmanii (Engelmann spruce). This work is being done in collaboration with researchers at the University of Colorado.

(Funding for this project was provided by NSF grant IBN-0212267)

Seasonal dynamics of microbial community structure and function in an Alpine dry meadow ecosystem

Our studies have shown that microbes in alpine dry meadow soils undergo dramatic seasonal dynamics in biomass, activity and community structure, and that these dynamics are integral to the alpine N cycle. We have also discovered that alpine soils harbor novel microbial communities, including the previously undescribed bacterial candidate division, 

SPAM

selected publications resulting from this work:

(full publications list)

D.A. Lipson, R.K. Monson, M. Weintraub (2006) Respiratory kinetics of the under-snow microbial community produce a large CO₂ source in a subalpine forest ecosystem. (in review)

ABSTRACT :  Soil respiration during winters is a principal component of the C balance of cold ecosystems, but it is uncertain how properties of specially-adapted winter microbial communities affect respiration rates.  In this study we collected soils from a subalpine coniferous forest throughout the year, and characterized the respiratory kinetics and composition of the actively-growing fraction of the microbial community.  Microbial communities from under snow had higher growth rates and lower growth yields than the summer and fall communities from exposed soils, leading to higher biomass-specific respiration rates.  Overall, bacteria had higher growth rates and lower growth yields than fungi.  The dominant bacteria from laboratory-incubated soil differed seasonally: faster-growing, cold-adapted Janthinobacterium species dominated in winter and slower-growing, mesophilic Burkholderia species dominated in summer.  We conclude that seasonal changes in microbial community composition and the rate and efficiency of microbial growth cause high rates of soil CO₂ loss from beneath the winter snowpack.

Monson* R.K., D.L. Lipson*, S.P. Burns, A.A. Turnipseed, A.C. Delany, M.W. Williams, S.K. Schmidt (2006) Forest soil respiration controlled by winter climate variation and microbial community composition. Nature (in press) (* these authors contributed equally)