Nancy C. Tuchman
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Professor CUERP Director Ph.D., 1988, University of Louisville Aquatic Ecology Phone: 773.508.2475 Fax: 773.508.8942 E-Mail: ntuchma@luc.edu My CV (PDF) |
RESEARCH INTERESTS
Atmospheric carbon dioxide levels are presently accumulating at their highest rate, and global concentrations are expected to double within the next 50 to 75 years. The ecological implications of this rapid change are numerous and critical. For example, the direct effects of CO2 enrichment on terrestrial plants include higher photosynthetic and growth rates and subsequent alteration of the chemical composition of the leaves. Typical chemical changes in leaf foliage include an increase in concentrations of plant defense compounds and a decrease in nitrogen, both of which negatively affect the food quality of the leaves for utilization by herbivores.In small streams and lakes, terrestrial leaf litter can account for up to 99% of the organic carbon that fuels the food webs. As an aquatic ecologist, my research focuses on the effects of elevated CO2-altered leaf litter on its utilization by aquatic microorganisms, detritivorous invertebrates, and fish.
I grow several species of trees under both ambient and elevated CO2 conditions in out door open-topped chambers at the University of Michigan Biological Station's Global Change Research Facility and harvest the altered leaf litter for experimentation in aquatic ecosystems. When leaf litter that is chemically altered by CO2 enrichment was introduced into natural stream and lake ecosystems, we measured significant reductions in microbial colonization and growth. In addition, when this leaf litter was fed to numerous species of aquatic macroinvertebrate detritivores, their consumption, assimilation efficiency, development and growth were significantly reduced. Further, when fish were fed the macroinvertebrates that we raised on this leaf litter, the fish growth rates were significantly lower. This series of experiments demonstrates a strong negative cascading effect of elevated CO2 on aquatic detrital food webs.
We are presently testing the combined effects of multiple global change parameters including elevated atmospheric CO2, increased global temperatures, and altered precipitation on the above ecological system.
REPRESENTATIVE PUBLICATIONS
Kominoski, J.S., P.A. Moore, R.G. Wetzel and N.C. Tuchman 2007. Elevated CO2 alters leaf-litter-derived dissolved organic carbon: Effects on stream periphyton and crayfish feeding preference. J. N. Am. Benthol. Soc. 26(4):662-671. (Full Text PDF)Angeloni, N.L., K.J. Jankowski, N.C. Tuchman, and J.J. Kelly. 2006. Effects of an invasive cattail species (Typha x glauca) on sediment nitrogen and microbial community composition in a freshwater wetland. FEMS Microbiol. Lett. 263:86-92. (Full Text PDF)
Tuchman, N.C., M.A. Schollett, S.T. Rier, and P. Geddes. 2006. Differential heterotrophic utilization of organic compounds by diatoms and bacteria under light and dark conditions. Hydrobiologia. 561:167-177. (Full Text PDF)
Janus, L.R., N.L. Angeloni, J. McCormack, S.T. Rier, N.C. Tuchman, and J.J. Kelly. 2005. Elevated atmospheric CO2 alters soil microbial communities associated with trembling aspen (Populus tremuloides) roots. Microb. Ecol. 50: 102-109. (Full Text PDF)
Frost, P.C., and N.C. Tuchman. 2005. Nutrient release rates and ratios by two stream detritivores fed leaf litter grown under elevated atmospheric CO2. Arch. Hydrobiol. 163(4): 463-477. (Full Text PDF)
Wetzel, R.G. and N.C. Tuchman. 2005. Effects of atmospheric CO2 enrichment and sunlight on degradation of plant particulate and dissolved organic matter and microbial utilization. Archiv fur Hydrobiol. 162(3):287-308.
Adams, J.A., N.C. Tuchman, and P.A. Moore. 2005. Effects of CO2-altered detritus on growth and chemically-mediated decisions in crayfish (Procambarus clarkii). J.N. Am. Benthol. Soc. 24(2):330-345.
Rier, S.T., N.C. Tuchman, and R.G. Wetzel. 2005. Chemical changes to leaf litter from trees grown under elevated CO2 and the implications for microbial utilization in a stream ecosystem. Can. J. Fish. Aquatic. Sci. 62: 185-194. (Full Text PDF)
Nancy C. Tuchman, Romi L. Burks, Christopher A. Call, John Smarrelli. 2004. Flow rate and vertical position influence ingestion rates of colonial zebra mussels (Dreissena polymorpha). Freshwater Biology 49(2): 191-198. (Full Text PDF)
Adams, J.A., N.C. Tuchman, and P.A. Moore. 2003. Atmospheric CO2 enrichment alters the chemical quality of leaf detritus: Impacts on foraging decisions of crayfish (Orconectes virilis). J. N. Am. Benthol. Soc. 22(3):410-422.
Tuchman, N.C., K.A. Wahtera, R.G. Wetzel, and J.A. Teeri. 2003. Elevated atmospheric CO2 alters leaf litter nutritional quality for stream ecosystems: An in situ leaf decomposition study. Hydrobiologia. 495(1-3):203-211.
Tuchman, N.C., S.T. Rier, K.A. Wahtera, R.G. Wetzel, N.M. Russo, G.M. Kilbane, L.M. Sasso, and J.A. Teeri. 2003. Nutritional quality of leaf detritus altered by elevated atmospheric CO2: Effects on development of mosquito larvae. Freshwat. Biol 48:1432-1439.
Tuchman, N.C., R.G. Wetzel, S.T. Rier, K.A. Wahtera, and J.A. Teeri. 2002. Elevated atmospheric CO2 lowers leaf litter nutritional quality for stream ecosystem food webs. Global Change Biol., 8(2):145-153.
Rier, S.T., N.C. Tuchman, R.G. Wetzel, and J.A. Teeri. 2002. Elevated CO2 induced changes in the chemistry of quaking aspen (Populus tremuloides) leaf litter: Subsequent decomposition and microbial response in a stream ecosystem. J. N. Am. Benthol. Soc. 21(1):16-27.
Burks, R.L., N.C. Tuchman, C.A. Call, J.E. Marsden. 2002. Colonial Aggregates: Effects of spatial position on zebra mussel responses to vertical gradients in interstitial water quality. J.N. Am. Benthol. Soc. 21(1):64-75.
