The APERG program is funded by the Reuben and Alice Wasser A.P.C. Education and Research Charitable Remainder Unitrust.
2006 Raymond Manganelli APERG Scholar:
Richard Lucas (2nd year of funding)
University of Pennsylvania
Project Title: The Effects of Atmospheric N Deposition on Ectomycorrhizal Community Structure and Function
Abstract
Over the past century, human activities have resulted in a substantial increase in atmospheric nitrogen (N) deposition throughout eastern North America, effectively doubling the amount of inorganic N entering terrestrial ecosystems. Increased atmospheric N deposition has the potential to alter terrestrial plant and microbial communities by increasing available NO3- and NH4+ in forest soil. We do not yet understand the importance or the implications of changes in the microbial community in terms of effects on forest ecosystems or ecosystem functions such as N cycling or carbon (C) storage. My work focuses on how atmospheric N deposition impacts soil C storage by examining lignin and protein decomposition activity, two compounds very abundant in forest soils and the substrates of microbial-produced extracellular enzymes, across a well-documented N deposition gradient from western Pennsylvania into Maine. I test hypotheses that organic N decomposition will be depressed in areas receiving high amounts of inorganic N deposition and secondly that the community structure of a symbiotic type of soil-dwelling fungi known as ectomycorrhizal fungi will shift from taxa able to make use of organic sources of N to taxa able to make use of inorganic N. These results support both of the hypotheses, organic N decomposition is decreased and that the ectomycorrhizal communities are significantly different in areas receiving high N deposition.
