Nitrogen biogeochemistry in temperate forest ecosystems - Nitrogen cycling is the mostly studied biogeochemical process in ecology and temperate forest is one of the most familiar ecosystems to general public and to professional ecologists, yet we still lack many mechanistic understandings in this fundamental process in temperate forests and such lack of understandings limits our abilities to interpret natural patterns of N cycling, to predict N cycling in human modified and managed systems, and to prevent a series of environmental consequences related to N alterations.
My lab is currently focusing on the mechanisms involved in N retention in temperate forests. Why some forests retain atmospheric deposited N while others don't? What factors affect year to year variations of N export from a forest ecosystem? Does plant species composition affect ecosystem N retention and if so, through what kinds of mechanisms?
What are the major forms of N losses? These questions have fundamental academic interests as well as practical applications. For example, if N from atmospheric deposition is mainly retained as soil organic N, that will create not only a nitrogen sink but also a carbon sin, consequently a negative feedback to global climate change. On the other hand, if most N is lost through denitrification in the form of N2O, then that contributes positively to global warming. Or nitrogen can be lost as nitrate to streams, contributing to local and regional eutrophications.
View our field sites and comment on the abstract of a recently submitted proposal to the NSF-Ecosystem panel.
Other related Nitrogen reference sources:
- National Atmospheric Deposition Program at http://nadp.sws.uiuc.edu
- A recent article on acid deposition in the Northeastern USA: Driscoll 2001 (.PDF, 709KB)
- Visit the N conference site at http://www.esa.org/n2001/
Urban ecology and the alterations of ecosystem processes - Urbanization is the most dramatic changes human beings have ever brought to the earth, fundamentally alters ecosystem structures, functions, species compositions and interactions. Urbanization is the necessity of civilization, understand ecological changes accompanying urbanization is thus essential. I have been involved in studying both "ecology in the city" (study individual patches in a city) and "ecology of the city" (treat the whole city as an ecosystem). Study ecosystem processes in urban remnant "natural" patches and human created patches allows us to understand the human impacts of urbanization, and ecosystem alleviation of human pollutions. Study city "as a whole" allows us to understand the constraints on urban development and the effect of urbanization to neighboring ecosystems from a landscape perspective.
- A recent article on the long-term studies of urban ecosystems: Grimm 2000 (.PDF, 255KB).
- Visit NSF supported Long Term Ecological Research sites at Urban Baltimore http://www.caryinstitute.org/science-program/research-projects/baltimore-ecosystem-study and Central-Arizona-Phoenix http://caplter.asu.edu/.
Landscape configuration and nutrient cycling at a watershed scale - One of the current directions of my lab is to understand nutrient cycling in a watershed with mixed land use, and to address non-point source pollution associated with various human activities. Many factors, including sizes of different land use patches, their relative positions, and different biogeochemical processes in different patches, affect nutrient retention and output at a watershed level. My personal interests lay on riparian ecosystem, an area sits in between terrestrial upland and aquatics with dynamic biogeochemical processes, large seasonal variations, and unique species compositions.
Plant-Soil interactions and soil microbial ecology - My interests in microbial ecology are mainly due to its importance in explaining biogeochemical patterns. I am particularly interested in microbes responsible for mycorrhizal symbiosis, nitrification, methane production and consumption, and lignin decomposition.
Additional Links of Interest:
- Ecological Society of America http://www.esa.org/
- National Science Foundation - Biology http://www.nsf.gov/home/bio/start.htm
- National Center for Environmental Researches (NCER) http://epa.gov/ncer/
- Long Term Ecological Research (LTER) http://www.lternet.edu/
- Great Lakes Research Consortium http://www.esf.edu/glrc/