Soil Biota and Terrestrial Nutrient Cycling
Melany C. Fisk
Assistant Professor
Ph.D., University of Colorado
Postdoctoral, University of Michigan
Melany Fisk's Lab and Course Webpage
I am interested in soil biota and their function in terrestrial ecosystem nutrient cycles. The soil component of ecosystems is amazingly diverse and structurally complex. Soil organisms include plant roots, mycorrhizal and saprophytic fungi, bacteria, and a multitude of soil fauna. Together, these form the detrital food web and are responsible for decomposition of organic matter and the recycling of plant nutrients. Research in my laboratory investigates the interactions of soil microorganisms with plants and with soil fauna, and the implications for organic matter and nutrient processing.
One aspect of my research explores soil microbial activity and transformations of nitrogen (N), a nutrient element that is critical for plant growth. My focus is on the feedbacks between plant production of the organic carbon that supports microbial growth, and the microbial processes that regulate availability of N for plant uptake. Goals of this work are to better understand specific mechanisms of plant influence over microbial growth and N turnover in forest ecosystems, and ways in which these mechanisms contribute to patterns of variation in the microbial cycling of N.
A second aspect of my research is the study of organisms responsible for organic matter decomposition and N recycling processes. The fine roots of forest trees are critical sources of organic carbon for the detrital food web; however, the identity and ecology of the organisms responsible for their decay remain a mystery. We are investigating the fungal species that decompose fine roots, and once they are identified, we will experimentally test the colonization dynamics of these decomposer communities. We are also exploring the influence of root carbon supply on trophic interactions between decomposer microorganisms and invertebrate fauna which graze them.
Selected Publications
Fisk, M.C., T. J. Fahey, P.M. Groffman, and P.J. Bohlen. 2004. Earthworm invasion, fine root distributions and soil respiration in north temperate forests. Ecosystems 7:55-62.
Fisk, M.C., K.F. Ruether, and J.B. Yavitt. 2003. Microbial activity and functional composition among northern peatland ecosystems. Soil Biology and Biochemistry 35: 591-692
Lawrence, B., M.C. Fisk, T.J. Fahey, and E.R. Su á rez. 2003. Influence of non-native earthworms on mycorrhizal colonization of sugar maple ( Acer saccharum Marsh). New Phytologist 157: 145-153.
Li, X., M.C. Fisk, T.J. Fahey, and P.J. Bohlen. 2002. Influence of earthworm invasion on soil microbial biomass and activity in a northern hardwood forest. Soil Biology and Biochemistry 34:1929-1937.
Fisk, M.C., D.R. Zak, and T.R. Crow. 2002. Nitrogen cycling and retention in old- and second-growth northern hardwood forests. Ecology 83: 73-87.
Fisk, M.C., and T.J. Fahey. 2001. Microbial biomass and nitrogen cycling response to fertilization and litter removal in young northern hardwood forests. Biogeochemistry 53: 201 - 223.
Fisk, M.C, S.K. Schmidt, and T.R. Seastedt. 1998. Topographic patterns of above- and belowground production and nitrogen cycling in alpine tundra. Ecology 79: 2253-2267.
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