Event Title

Quantifying Benthic Nitrogen Fluxes in Puget Sound, Washington—A Review of Available Data

Presentation Abstract

In Puget Sound, Washington, underrepresenting or neglecting benthic flux as a source of nitrogen to marine waters can result in ineffective management actions and can lead to chronic water-quality problems, such as hypoxia, in sensitive areas. Shallow areas near the shores of Puget Sound are most likely to experience low levels of dissolved oxygen because of the combination of relatively low circulation, warm summer water temperatures, and proximity to watershed nutrient contributions. In these shallow areas, benthic nutrient fluxes may be the dominant local source of nitrogen. Studies of benthic fluxes of nutrients have been quantified in very few areas in the Puget Sound and more sediment flux data, as well as detailed information about controls on benthic fluxes, are needed. To address this data gap, we conducted an extensive search of the literature for data related to benthic nitrogen fluxes in Puget Sound. A total of 138 individual flux chamber measurements and 38 sets of diffusive fluxes were compiled. Of the diffusive fluxes, 35 new datasets were located, and new flux calculations are presented. In total, 65 new diffusive flux calculations are provided across all nitrogen species (ammonium, nitrate, and nitrite). Data analysis of this newly compiled benthic flux dataset showed that deep (greater than 50 meters) water tended to have lower flux values than shallow (less than 50 meters) depths. Additionally, variability in flux at the shallow depths was greater, possibly indicating a more dynamic interaction between the benthic and pelagic environments. The overall range of bottom temperatures from studies in the Puget Sound area was small (5–16 degrees Celsius) and only ammonium flux showed any pattern with temperature with increased variability at temperatures greater than 12 degrees Celsius. We identify several areas needed for future research from this newly compiled data set. As more is learned about the role of benthic nitrogen fluxes in Puget Sound, this information can be incorporated into coupled sediment and biogeochemical models to better capture nutrient and oxygen dynamics, and to provide improved information for managers of Puget Sound resources.

Session Title

Session S-06C: Water Quality III

Conference Track

Water Quality

Conference Name

Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)

Document Type

Event

Start Date

1-5-2014 5:00 PM

End Date

1-5-2014 6:30 PM

Location

Room 6C

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

This document is currently not available here.

Share

COinS
 
May 1st, 5:00 PM May 1st, 6:30 PM

Quantifying Benthic Nitrogen Fluxes in Puget Sound, Washington—A Review of Available Data

Room 6C

In Puget Sound, Washington, underrepresenting or neglecting benthic flux as a source of nitrogen to marine waters can result in ineffective management actions and can lead to chronic water-quality problems, such as hypoxia, in sensitive areas. Shallow areas near the shores of Puget Sound are most likely to experience low levels of dissolved oxygen because of the combination of relatively low circulation, warm summer water temperatures, and proximity to watershed nutrient contributions. In these shallow areas, benthic nutrient fluxes may be the dominant local source of nitrogen. Studies of benthic fluxes of nutrients have been quantified in very few areas in the Puget Sound and more sediment flux data, as well as detailed information about controls on benthic fluxes, are needed. To address this data gap, we conducted an extensive search of the literature for data related to benthic nitrogen fluxes in Puget Sound. A total of 138 individual flux chamber measurements and 38 sets of diffusive fluxes were compiled. Of the diffusive fluxes, 35 new datasets were located, and new flux calculations are presented. In total, 65 new diffusive flux calculations are provided across all nitrogen species (ammonium, nitrate, and nitrite). Data analysis of this newly compiled benthic flux dataset showed that deep (greater than 50 meters) water tended to have lower flux values than shallow (less than 50 meters) depths. Additionally, variability in flux at the shallow depths was greater, possibly indicating a more dynamic interaction between the benthic and pelagic environments. The overall range of bottom temperatures from studies in the Puget Sound area was small (5–16 degrees Celsius) and only ammonium flux showed any pattern with temperature with increased variability at temperatures greater than 12 degrees Celsius. We identify several areas needed for future research from this newly compiled data set. As more is learned about the role of benthic nitrogen fluxes in Puget Sound, this information can be incorporated into coupled sediment and biogeochemical models to better capture nutrient and oxygen dynamics, and to provide improved information for managers of Puget Sound resources.