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Kevin Mueller

The Influence of Trees on Soil Biogeochemistry

Ph.D. in Ecology and Biogeochemistry. 2011.

Co-Advisors: David Eissenstat & Kate Freeman (Geosciences)

Email: kevin.e.mueller@gmail.com

Present position: 

Postdoctoral research associate

U.S. Department of Agriculture

Agricultural Research Service

Rangeland Resources Research Unit

http://kevinemueller.wordpress.com

Collaborators: Jon Chorover, Jacek Oleksyn, Peter Reich, Sarah Hobbie, Susan Trumbore

Kevin was partially supported by NSF IGERT: Biogeochemical Research Initiative for Education, NSF DOE, the Ecology Program and the Plant Science Department.

Despite the prominent position of soil organic matter (SOM) in the global carbon (C) cycle and the promise for temperate forests to act as C sinks, the biotic controls over recalcitrant SOM formation in these ecosystems are not well understood. We are investigating plant controls on SOM formation and C sequestration in soils at a unique temperate forest common garden experiment in central Poland. The accumulation of plant inputs above- and belowground for 35 years in 14 species plots provides a powerful tool for exploration of the influence of tree species on soil C dynamics. Specifically, we plan to examine the relationship between SOM and plant characteristics such as potential growth rate, nutrient conservation strategy, and plant litter production and chemistry. Does variation in certain measurable plant traits influence soil C dynamics in a predictable fashion? Bomb radiocarbon analysis will be utilized to estimate recent C input and stability (C sink potential) in soil. In addition, we are using GC-MS and NMR analysis of the biochemical composition of SOM to determine the relative importance of plant inputs (root and leaf material) to soil C storage. The relationships revealed in this study will be useful in modeling the effects of changes in tree species composition on C dynamics in temperate forests.

Publications:

Mueller, K.E., Polissar, P.J., Oleksyn, J., and Freeman, K.H.  (in press). Differentiating temperate tree species and their organs using lipid biomarkers in leaves, roots, and soils.  Organic Geochemistry

Mueller, K.E., Hobbie, S.E. , Oleksyn, J., Reich, P.B. and D.M. Eissenstat. 2012. Do evergreen and deciduous trees have different effects on net N mineralization in soil? Ecology 93:1463-1472.

Mueller, K.E., Eissenstat, D.M, Hobbie, S.E., Oleksyn, J., Jagodzinski, A.M., Reich, P.B., Chadwick, O.A., and Chorover, J. 2012. Tree species effects on coupled cycles of carbon, nitrogen, and acidity in mineral soils at common garden experiment.  Biogeochemistry (DOI: 10.1007/s10533-011-9695-7).

Mueller, K.E., Diefendorf, A.F., Freeman, K.H., and D.M. Eissenstat. 2010. Appraising the roles of nutrient availability, global change, and functional traits during the angiosperm rise to dominance. Ecology Letters 13:E1-E6

Freeman, K.H., Mueller, K.E., Diefendorf, A.F., Wing, S.L., and Koch, P.L.  2011. Clarifying the influence of water availability and plant types on carbon isotope discrimination by C3 plants. Proceedings of the National Academy of Sciences of the USA, 108, E59-E60.

*Diefendorf, A.F., *Mueller, K.E., Wing, S.L., Koch, P.L., and Freeman, K.H.  2010.  Global patterns in leaf 13C discrimination and implications for studies of past and future climate change. Proceedings of the National Academy of Sciences of the USA, 107, 5738-5743.

Mueller, K.E. 2011. The Influence of Trees on Soil Biogeochemistry . PhD thesis. The Pennsylvania State University. 142pp.

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Mueller, K.E., Müller, C.W., Oleksyn, J., Eissenstat, D.M., and Freeman, K.H. Controls on the concentration of plant-derived lipids in forest soils. submitted: Soil Biology & Biochemistry.