Donald R. Zak, Ph.D.

Associate Dean for Academic Affairs; Burton V. Barnes Collegiate Professor of Ecology

Ph.D. 1987, Michigan State University

M.S. 1983, University of Idaho

B.S. Cum Laude 1981, Ohio State University

Don Zak holds a joint appointment in the department of Ecology and Evolutionary Biology, College of Literature, Science, and Arts. His research investigates links between the composition and function of soil microbial communities and the influence of microbial activity on ecosystem-level processes. This work draws on ecology, microbiology, and biochemistry and is focused at several scales of understanding, ranging from the molecular to the ecosystem scale. Current research centers on understanding the link between plant and microbial activity within terrestrial ecosystems, and the influence climate change may have on these dynamics. Teaching includes courses in soil ecology and ecosystem ecology.

Awards and Grants:
Atmospheric nitrogen deposition and molecular mechanisms enhancing soil carbon storage. Sponsor: DoE Biological and Environmental Research

Ecosystem response to elevated CO2 and O3 is controlled by plant-microbe interactions in soil. Sponsor: DoE Program for Ecosystem Research

Long-term ecosystem response to chronic atmospheric nitrogen deposition. Sponsor: NSF Long-Term Research in Environmental Biology Program (LTREB)

Research Interests:
My research investigates connections between microbial community composition and function and the importance of microbial activity in regulating ecosystem-level processes. This work draws on microbial ecology and plant physiology, and it is focused at several scales of understanding. Plants respond to environmental factors by altering growth and longevity of fine roots, which, in part, control the amount and types of organic substrates available for microbial metabolism in soil. I have worked to understand how changes in belowground plant growth influence the composition and function of soil microbial communities. Stable isotopes and molecular techniques are the primary tools I have used to accomplish this task. My work has elucidated mechanisms of plant-microbe competition for inorganic nitrogen and the interdependence of plant and microbial productivity in a wide range of terrestrial ecosystems. Much of my current work centers on understanding the link between plant and microbial activity within terrestrial ecosystems, and the influence climate change may have on these dynamics.

Teaching Interests:
My teaching builds an understanding of the processes controlling the flow of energy and nutrients within terrestrial ecosystems and how these dynamics are altered by human activity. I accomplish this through a series of undergraduate and graduate courses that focus on microbial ecology and ecosystem ecology. In Soil Ecology (NRE 430/BIO 498), I provide students with the fundamental principles of soil science, stressing the integration of concepts into an understanding of ecosystem-level processes. I complement formal lectures with informal teaching in field and laboratory settings, an approach that has been useful for putting concepts and theory into action. Ecosystem Ecology (NRE 476/BIO 476) is a lecture course that focuses on understanding the physical, chemical and biochemical processes regulating the dynamics of terrestrial and aquatic ecosystems; it is team taught by myself and Dr. George Kling. We discuss classic and current topics in ecology that have built our understanding of ecosystem organization and function. Some aspects of population and community ecology are presented to gain an in-depth understanding of how and why ecosystems change in time and space. The course integrates across disciplines of physiological, population, and community ecology to understand how and why ecosystems differ in composition, structure, and function. Students are expected to have a solid background in biology and ecology. We also expect that students will be able to use principles of mathematics, physics, chemistry and biology as tools to understand ecological processes occurring at the ecosystem level.

Current/Recent Teaching:
General Ecology – BIO/ENVIRON 281
Soil Ecology – EEB 489/ENVIRON 430
Ecosystem Ecology – EEB/ENVIRON 476
Ecosystem Science in the Rocky Mountains - GEOLOGY/ENVIRON 341

Recent Publications

Gan, H., D.R. Zak and M.D. Hunter. 2013.  Chronic atmospheric N deposition decreases microarthropod density in a northern hardwood ecosystem. Ecological Applications 23: 1311-1321.

Van Diepen, L.T.A., D.R. Zak and E.M. Entwistle. 2013. Active arbuscular mycorrhizal fungal communities are altered by simulated N deposition in northern hardwood forests. Applied Soil Ecology 72: 62-68.

Freedman, Z., S.D. Eisenlord, D.R. Zak, K Xue, X. He and J. Zhou. 2012. Chronic atmospheric N deposition suppresses functional genes mediating N cycling and causes assemblage dispersion in a northern hardwood forest ecosystem Soil Biology and Biochemistry 66: 130-138.

Entwistle, E.M., D.R. Zak, and I.P. Edwards. 2013.  Long-term simulated nitrogen deposition alters the composition of fungi active in forest floor. Soil Science Society of America Journal 77: 1648-1658.

Gan, H., D.R. Zak and M.D. Hunter. 2013. Trophic stability of soil orabatid mites in the face of environmental change. Soil Biology and Biochemistry 68: 71-77.

Cline, L.C. and D.R. Zak. 2013. Ecological factors structuring fungal biogeography and functional potential along a glacial chronosequence in the Upper Great Lakes region. Environmental Microbiology doi:10.1111/1462-2920.12281.

Kellner, H., P. Luis, M.J. Pecyna, D. Kapturska, D. Krüger, D.R. Zak, R. Marmeisse, M. Vandenbol and M. Hofrichter. 2014 Widespread occurrence of expressed fungal secretory peroxidases in forest soils. PLoS One 9: e95557.

Talhelm, A.F., K.S. Pregitzer, M.E. Kubiske, D.R. Zak et al.  2014. Anthropogenic carbon dioxide and ozone offset ecosystem C storage in forests. Global Change Biology in press.

Zak, D.R. 2014. Ecosystem succession and nutrient retention: Vitousek and Reiners’ hypothesis.  Bulletin of the Ecological Society of America in press.

Freedman, Z., and D.R. Zak. 2014. A bacterial role in lignin decomposition under future rates of atmospheric N deposition. Applied & Environmental Microbiology in press.