Skip to main content
Duke University Libraries
DukeSpace Scholarship by Duke Authors
  • Login
  • Ask
  • Menu
  • Login
  • Ask a Librarian
  • Search & Find
  • Using the Library
  • Research Support
  • Course Support
  • Libraries
  • About
View Item 
  •   DukeSpace
  • Duke Scholarly Works
  • Scholarly Articles
  • View Item
  •   DukeSpace
  • Duke Scholarly Works
  • Scholarly Articles
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

Thumbnail
View / Download
5.0 Mb
Date
2012-05-22
Authors
Heffernan, JB
Albertin, AR
Fork, ML
Katz, BG
Cohen, MJ
Repository Usage Stats
183
views
205
downloads
Abstract
Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N2 is highly variable in space and inversely correlated with dissolved oxygen (O2). Negative relationships between O2 and δ15N NO3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15N:18O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32 % of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ15N NO3 based on denitrification progression suggest that isotopically-enriched nitrate (NO3-) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs. © Author(s) 2012.
Type
Journal article
Permalink
https://hdl.handle.net/10161/8359
Published Version (Please cite this version)
10.5194/bg-9-1671-2012
Publication Info
Heffernan, JB; Albertin, AR; Fork, ML; Katz, BG; & Cohen, MJ (2012). Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer. Biogeosciences, 9(5). pp. 1671-1690. 10.5194/bg-9-1671-2012. Retrieved from https://hdl.handle.net/10161/8359.
This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.
Collections
  • Scholarly Articles
More Info
Show full item record

Scholars@Duke

Megan Fork

Teaching Assistant
Megan Fork is a current PhD candidate in Environmental Science & Policy at Duke's Nicholas School of the Environment.
Heffernan

James Brendan Heffernan

Associate Professor of Ecosystem Ecology and Ecohydrology
I am interested in major changes in ecosystem structure, particularly in streams, rivers and wetlands. My work focuses on feedbacks among ecological, physical, and biogeochemical processes, and uses a wide range of tools and approaches. I am particularly interested in projects that address both basic ecological theory and pressing environmental problems. Increasingly, we are applying tools and theories developed for local ecosystems to better understand ecological patterns and mechanisms at regi
Alphabetical list of authors with Scholars@Duke profiles.
Open Access

Articles written by Duke faculty are made available through the campus open access policy. For more information see: Duke Open Access Policy

Rights for Collection: Scholarly Articles


Works are deposited here by their authors, and represent their research and opinions, not that of Duke University. Some materials and descriptions may include offensive content. More info

Make Your Work Available Here

How to Deposit

Browse

All of DukeSpaceCommunities & CollectionsAuthorsTitlesTypesBy Issue DateDepartmentsAffiliations of Duke Author(s)SubjectsBy Submit DateThis CollectionAuthorsTitlesTypesBy Issue DateDepartmentsAffiliations of Duke Author(s)SubjectsBy Submit Date

My Account

LoginRegister

Statistics

View Usage Statistics
Duke University Libraries

Contact Us

411 Chapel Drive
Durham, NC 27708
(919) 660-5870
Perkins Library Service Desk

Digital Repositories at Duke

  • Report a problem with the repositories
  • About digital repositories at Duke
  • Accessibility Policy
  • Deaccession and DMCA Takedown Policy

TwitterFacebookYouTubeFlickrInstagramBlogs

Sign Up for Our Newsletter
  • Re-use & Attribution / Privacy
  • Harmful Language Statement
  • Support the Libraries
Duke University