Ammonia Exchange between the Atmosphere and the Surface Waters at Two Locations in the Chesapeake Bay

Randolph K. Larsen, III, Joseph C. Steinbacher, and Joel E. Baker*
Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, 1 Williams Street, Solomons, Maryland 20688
Environ. Sci. Technol., 2001, 35 (24), pp 4731–4738
DOI: 10.1021/es010755l
Publication Date (Web): November 8, 2001
Copyright © 2001 American Chemical Society

Abstract

Excess phytoplankton production, which contributes to hypoxic conditions, is nitrogen limited in the Chesapeake Bay during the summer months. Therefore, understanding the flux of ammonia by direct deposition to the biologically active surface layer is critical to understanding the nutrient dynamics of the bay. This paper presents the results of a 2-yr study measuring gaseous ammonia (NH3) and aerosol ammonium (NH4+) in Baltimore and Solomons, MD, from which direct atmospheric loading of total ammonia (Nt = NH3 + NH4+) to the Chesapeake Bay is estimated. Mean atmospheric concentrations of total ammonia for Baltimore and Solomons were 2.7 ± 1.7 and 1.0 ± 0.8 μg of N m-3, respectively. Monte Carlo estimates of gross dry deposition ranged from <100 to 4900 μg of N m-2 d-1. However, based upon water quality parameters, Monte Carlo estimates of gross volatilization of NH3 were calculated to range from <100 to 7700 μg of N m-2 d-1. The resulting net air−sea exchange flux varied seasonally from a net deposition into the water during the winter to a net volatilizing into the atmosphere during the summer. A total of 60% of the paired air−water samples had flux estimates that were not significantly different than equilibrium at the 90% confidence interval. The gross deposition, gross volatilization, and net air−sea fluxes were greater and more variable in Baltimore relative to the rural site. Atmospheric ammonia concentrations decrease during the winter at the rural site. However, the net exchange is still into the water due to an exponential decrease in [NH3]eq with temperature. These results indicate that the nitrogen-limited Chesapeake Bay can act as a source of ammonia to the local atmosphere.

View: Full Text HTML | Hi-Res PDF | PDF w/ Links

Citing Articles

View all 12 citing articles

Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.

This article has been cited by 2 ACS Journal articles (2 most recent appear below).

Tools

SciFinder Links

SciFinder subscribers: Click to sign in | Not a SciFinder subscriber? Learn more at www.cas.org

Explore by:

History

  • Published In Issue December 15, 2001
  • Received for review March 16, 2001
    Revised manuscript received September 25, 2001
    Accepted September 28, 2001

Recommend & Share

  • Share on ACS NetworkACS Network
  • Add to FacebookFacebook
  • Tweet ThisTweet This
  • Add to CiteULikeCiteULike
  • Add to NewsvineNewsvine
  • Digg ThisDigg This
  • Add to DeliciousDelicious

Related Content

Other ACS content by these authors: