Overview
Our research focuses on the ecological and biogeochemical processes that determine ecosystem structure and functioning at local, regional, and global levels. Study systems include temperate forest and arctic tundra ecosystems. Our research aims to develop mechanistic understandings of how ecosystems respond to climate change, air pollution, and physical disturbances. Specifically, our research examines how soil biota, plants, and climate interact to determine ecosystem structure and stability.
Research Projects
| Detritus Input & Removal Treatment Project (DIRT) |  |
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| The goal of the DIRT project is to assess the role of plant litter (both from above and belowground) in controlling the accumulation and turnover of organic matter and nutrients in forest soils . This is done by systematically increasing or decreasing inputs of litter from aboveground and by either allowing or excluding tree roots from growing into permanent plots located in temperate forests. DIRT sites are located in Oregon, Wisconsin, Michigan, Pennsylvania, Massachusetts, and Hungary. | |||
| DIRT | Data | Photos | |
| Arctic Research Project |  |
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| The lab has quantified ecosystem carbon flows in tundra ecosystems near the Toolik Lake LTER site in Alaska. We labeled Wet Sedge, Moist Acitic Tussock, and Nonacidic Tussock ecosystems with 14CO2 to track carbon movement through the ecosystems. No measurements are currently planned for the plots. See collaborator George Kling's website for more information. We have also studied nutrient cycling along a riverside toposequence. | |||
| Arctic | Data | Photos | |
| Temperate Forest Nitrogen Projects |  |
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In 1991 and 1992 we labeled the Bear Brook Watershed in Maine with trace 15N ammonium sulfate. The experiment fertilized one catchment in the watershed with ammonium sulfate while a second catchment served as the control. We have since tracked the fate of the label through the watershed. We have also collaborated with colleagues at Harvard Forest and the University of New Hampshire on a chronic nitrogen ammendment study. The Chronic N study applied two levels of nitrogen to pine and hardwood stands at Harvard Forest since 1988. We applied 15N to the plots in 1991 and 1992 and have tracked its movement into soils and vegetation. Our most recent forest nitrogen research is located at the University of Michigan Biological Station. We are measuring the changes to the nitrogen cycle in response to the Forest Accelerated Succession ExperimenT (FASET). The experiment accelerates succesion by girdling early successional Populus and Betula species thereby releasing understory and codominant species. Through 15N natural abundance measurements of ecosystem nitrogen pools and through 15N labeling we are are monitoring how the nitrogen cycle responds to the girdling perturbation and influences succession.
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| Nitrogen | Data | Photos | |
