Anthropogenic Pollutant Effects on Aquatic Ecosystems Impacts of Atmospheric Nitrogen Deposition on Phytoplankton Dynamics and Eutrophication

EPA Grant Number: R825243
Title: Anthropogenic Pollutant Effects on Aquatic Ecosystems Impacts of Atmospheric Nitrogen Deposition on Phytoplankton Dynamics and Eutrophication
Institution: University of North Carolina at Chapel Hill , Rutgers University - New Brunswick
EPA Project Officer: Chung, Serena
Project Period: October 1, 1996 through September 30, 1999
Project Amount: $382,789
RFA: Air Quality (1996) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Water Quality , Air


Rainfall contains a variety of organic and inorganic chemical species in both dissolved and particulate forms. Atmospherically-derived nitrogen (AND) is a dynamic mixture of biologically-available dissolved inorganic (NO3-, NO2-, NH4+; DIN) and organic compounds (amino acids, organonitrates, PAN, urea; DON) commonly found in rainfall. In nutrient-sensitive ecosystems, the addition of growth-limiting nutrients can have profound effects on plant community structure and function. Phytoplankton provide ideal "model" plant communities for evaluating ecosystem responses to atmospherically-derived pollutant stress. The main objective of this proposed research is to evaluate ecosystem sensitivity to pollutant stress by examining phytoplankton community responses to ADN compounds. The responses of aquatic ecosystems to emerging and evolving specific atmospheric N compounds in rainfall are virtually unknown and provide the focus for this proposal. The working hypothesis is that contrasting ADN compound reactivities translate into physiologically and taxonomically-distinct phytoplankton growth responses that result in changes in community composition. The proposed research will quantitatively measure taxa-specific responses of the phytoplankton community (species composition, productivity, growth rates, photophysiology) to the range of ADN compounds found in rainfall in Eastern North Carolina. From an ecological perspective, it will be determined how different ADN compounds influence the biodiversity and function of natural phytoplankton communities. The overall research objective is to establish a functional understanding of taxa-specific responses of phytoplankton to stress induced by different chemical forms of ADN inputs, their impacts on phytoplankton community function (productivity), photophysiology, and compositional (biodiversity) dynamics. This will be accomplished by quantifying the impacts of N sources having DIN (NO3-, NH4+) and DON (urea) compositions representative of atmospheric new N inputs on phytoplankton primary productivity, growth rates, photophysiology, and biodiversity in representative N-limited riverine and estuarine waters. The proposed research will improve our functional understanding and enhance predictability of the relationships between ADN inputs and their manifestation in terms of phytoplankton production, biodiversity responses, and eutrophication dynamics to anthropogenic pollutant stress.

Publications and Presentations:

Publications have been submitted on this project: View all 63 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 16 journal articles for this project

Supplemental Keywords:

air, ambient air, atmosphere, watersheds, troposphere, ecological effects, ecosystem, biology, ecology, southeast, North Carolina, NC, Region 4., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Atmospheric Sciences, Ecological Risk Assessment, Watersheds, Ecological Indicators, anthropogenic processes, atmospheric processes, nutrient transport, aquatic ecosystem, ecological exposure, anthropogenic stress, eutrophication, precipitation, biodiversity, nutrient sensitive ecosystems, atmospheric nitrogen deposition, ADN compounds, atmospheric nitrogen deposits, phytoplankton dynamics, nutrient stress, aquatic ecosystems, North Carolina (NC), rainfall

Progress and Final Reports:

  • 1997
  • 1998
  • Final Report