U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Long-term Ecosystem Research Highlights Fate of Nitrogen in Rainfall
Published: December 27, 2004
Posted: January 13, 2005

Department of Energy studies on Walker Branch Watershed in the Departments Oak Ridge (Tennessee) National Environmental Research Park showed that stream ecosystems can help prevent nitrogen pollutants from reaching downstream lakes, estuaries, and the ocean. Fossil fuel use is increasing the amount of nitrogen in rainfall in many parts of the United States, and inputs of this nitrogen to aquatic ecosystems can result in harmful algal blooms and drinking water contamination. Combining computer simulation and data from 12 years of field measurements, scientists at Oak Ridge National Laboratory found that biological organisms in streams removed about 20% of the nitrate nitrogen entering the stream from the watershed, thus reducing the concentration of nitrate exported downstream. The removal of nitrate nitrogen was highly seasonal; it was greatest in autumn (due to uptake by bacteria and fungi growing on newly fallen leaves trapped in the stream) and in early spring (due to high rates of uptake by algae before the stream becomes heavily shaded by new leaves in the deciduous forest overhead). These results are consistent with studies at the Hubbard Brook Experimental Forest (New Hampshire) and elsewhere showing that streams can reduce the downstream transport of nitrate nitrogen, and demonstrate the important role of streams in preventing high nitrate export and the eutrophication of downstream aquatic ecosystems. This study was recently documented in the journal Biogeochemistry.

Contact: Jeff Amthor, SC-74, (301) 903-2507
Topic Areas:

  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Microbes and Communities
  • Research Area: Computational Biology, Bioinformatics, Modeling

Division: SC-23.1 Climate and Environmental Sciences Division, BER
      (formerly SC-74 Environmental Sciences Division, OBER)


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)