Lotic Intersite Nitrogen eXperiment II (LINX II): a cross-site study of the effects of anthropogenic land use change on nitrate uptake and retention in 72 streams across 8 different biomes (2003 – 2006).

  • Creator(s): Clifford N. Dahm, Walter K. Dodds, Stanley V. Gregory, Sherri L. Johnson, Judy L. Meyer, Patrick J. Mulholland, Jackson R. Webster, Nancy B. Grimm, William H. McDowell, Jennifer L. Tank, Stephen K. Hamilton, Bruce J. Peterson, H. Maurice Valett, Robert O. Jr. Hall
  • PI(s): Patrick J. Mulholland, Clifford N. Dahm, Walter K. Dodds, Stanley V. Gregory, Nancy B. Grimm, Robert O. Jr. Hall, Stephen K. Hamilton, Sherri L. Johnson, Bruce J. Peterson, William H. McDowell, Judy L. Meyer, Jennifer L. Tank, H. Maurice Valett, Jackson R. Webster
  • Originator(s): Patrick J. Mulholland
  • Other researcher(s): Clay P. Arango, Linda R. Ashkenas, Jake J. Beaulieu, Melody J. Bernot, Amy J. Burgin, Lee W. Cooper, Chelsea L. Crenshaw, Stuart G. Findlay, Ashley M. Helton, Laura T. Johnson, Eugènia Martí, Jeff L. Merriam, B. R. Niederlehner, Jonathan M. O'Brien, Geoffrey C. Poole, Jody D. Potter, Richard W. Sheibley, Daniel J. Sobota, Suzanne M. Thomas, Kym Wilson, Lydia Zeglin
  • Dates of data collection: May 1 2003 - Mar 1 2006
  • Data collection status: Study collection is completed and no new collection is planned
  • Data access: Online
  • DOI:
  • Access constraint: Please acknowledge originators when using this dataset as source material in reports or publications. While strong efforts are made to ensure data set accuracy, complete accuracy of every data set cannot be guaranteed. The LINX investigators have made every effort to provide and maintain accurate, complete, usable, and timely information. These data and information are provided with the understanding that they are not guaranteed to be correct or complete. Users are cautioned to consider carefully the nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data and information. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.
  • Last update: May 6 2015 (Version 3)
<Citation>     <Acknowledgement>     <Disclaimer>    
Dahm, C.; Dodds, W.; Gregory, S.; Johnson, S.; Meyer, J.; Mulholland, P.; Webster, J.; Grimm, N.; McDowell, W.; Tank, J.; Hamilton, S.; Peterson, B.; Valett, H.; Hall, R. 2015. Lotic Intersite Nitrogen eXperiment II (LINX II): a cross-site study of the effects of anthropogenic land use change on nitrate uptake and retention in 72 streams across 8 different biomes (2003 – 2006).. Lotic Intersite Nitrogen Experiment. Forest Science Data Bank, Corvallis, OR. [Database]. Available: Accessed 2023-12-11.
This work was supported by National Science Foundation (NSF) grant DEB-0111410 to the University of Tennessee, NSF Long Term Ecological Research (LTER) grants to some of the individual sites, and numerous smaller grants and fellowships to other institutions. More than 100 students and scientists gathered the information for the experiments. The NSF LTER network, U.S. Forest Service, National Park Service and many municipal and private landowners facilitated the field research. The NSF DEB provided supplemental funding to organize the online database. When using these data, we suggest you cite one or both of these two core LINX papers as appropriate: Mulholland, P. J, , R. O. Hall, Jr., D. J. Sobota, W. K. Dodds, S. Findlay, , N. B. Grimm, S. K. Hamilton, W. H. McDowell, J. M. O’Brien, J. L. Tank, L.R. Ashkenas, L. W. Cooper, C. N. Dahm, S. V. Gregory, S. L. Johnson, J. L. Meyer, B. J. Peterson, G. C. Poole, H. M. Valett, J. R. Webster, C. Arango, J. J. Beaulieu, M. J. Bernot, A. J. Burgin, C. Crenshaw, A. M. Helton, L. Johnson, B. R. Niederlehner, J. D. Potter, R. W. Sheibley, and S. M. Thomas. 2009. Nitrate removal in stream ecosystems measured by 15N addition experiments: denitrification. Limnology and Oceanography 54: 666-680. Hall, R. O., Jr., J. L. Tank, D. J. Sobota, P. J. Mulholland, J. M. O’Brien, W. K. Dodds, J. R. Webster, H. M. Valett, G. C. Poole, B. J. Peterson, J. L. Meyer, W. H. McDowell, S. L. Johnson, S. K. Hamilton, N. B. Grimm, S. V. Gregory, C. N. Dahm, L. W. Cooper, L.R. Ashkenas, S. M. Thomas, R. W. Sheibley, J. D. Potter, B. R. Niederlehner, L. Johnson, A. M. Helton, C. Crenshaw, A. J. Burgin, M. J. Bernot, , J. J. Beaulieu, C. Arango. 2009. Nitrate removal in stream ecosystems measured by 15N addition experiments: total uptake. Limnology and Oceanography 54: 653-665.
While substantial efforts are made to ensure the accuracy of data and documentation, complete accuracy of data sets cannot be guaranteed. All data are made available "as is". The FSDB shall not be liable for damages resulting from any use or misinterpretation of data sets.
The LINX II (Lotic Intersite Nitrogen eXperiment) project was designed to quantify the rates and mechanisms of nitrate retention in streams using stable isotope tracer additions. The study encompassed 72 stream reaches spread across 8 North American biomes. Within each biome, 9 streams were selected in three watershed land-use categories: 3 reference, 3 agricultural, and 3 urbanized. The core of the study was a 24-hour release of 15N- labeled nitrate. Prior to the isotope addition, physical, chemical and biological characteristics of the stream were measured. The measurements included, but were not limited to, dissolved nutrient concentrations, dissolved conservative tracer additions (to quantify hydraulic and hyporheic retention, velocity and discharge), standing stocks of primary uptake biota (including suspended and benthic particulate materials) as well as channel dimensions, photosynthetically active radiation, and water temperature. During the isotope release, whole stream rates of ecosystem metabolism were quantified (including quantification of re-aeration coefficients using tracer gas additions), and concentrations of 15N-labeled NO3, NH4, N2 and N2O were measured. Immediately following the isotope addition, 15N uptake by aquatic organisms was quantified by sampling biomass components on the stream bed. The data generated from these 72 stream reaches were used to develop a stream nitrogen retention model for each biome, which was expanded to entire drainage networks to predict nitrogen fluxes. The LINX II study demonstrated how biotic uptake of nitrate and denitrification increased with increasing nitrate concentrations. However, the efficiency of total uptake and denitrification actually declined with increasing nitrate concentrations (such as those seen on agricultural or urbanized streams), yielding higher rates of dissolved nitrogen exports downstream. The datasets presented here consist of the primary data collected by the LINX II study participants.

Study Description Study Site Map Download Study Location Information: (CSV)
Ecological Metadata Language: (EML)
1Site locations & characteristics (May 1 2003 - Mar 1 2006)METADATADATA
2Conditions & standards for isotope release (15N Solute Info) (May 1 2003 - Mar 1 2006)METADATADATA
3Concentrations of dissolved chemical species & 15N label of nitrogen species (15N Solutes) (May 1 2003 - Mar 1 2006)METADATADATA
4N2 & N2O gas sampling: concentrations & 15N labels (May 1 2003 - Mar 1 2006)METADATADATA
5Suspended Particulate Organic Material (SPOM) (May 1 2003 - Mar 1 2006)METADATADATA
6Biomass of primary food web components (May 1 2003 - Mar 1 2006)METADATADATA
715N isotope data for food web compartments (May 1 2003 - Mar 1 2006)METADATADATA
8Well or tributary samples (Chemistry) (May 1 2003 - Mar 1 2006)METADATADATA
9Conservative gas tracer releases (May 1 2003 - Mar 1 2006)METADATADATA
10Conditions & parameters for calculations of ecosystem metabolism (May 1 2003 - Mar 1 2006)METADATADATA
11Data from recording sondes for ecosystem metabolism measurements (May 1 2003 - Mar 1 2006)METADATADATA
12Parameters for conservative solute tracer releases (May 1 2003 - Mar 1 2006)METADATADATA
13Conservative solute tracer data (May 1 2003 - Mar 1 2006)METADATADATA

 LINX II Stream 15N Experiment Protocols (rev5) - Standard protocols for field & labortory components
 LINX II Collaborators - List of personnel involved in LINXII study
 LINX II Publications - Publication list using LINX II data as of 2014
 LINX II Site Descriptions - Descriptive narrative of LINX II sites by siteid
 Example spreadsheets from a LINXII site (NC_AGR_2) - Entire workbook, including data & models, from site NC_AGR_2. Provided as an example of complex workflow.
 Blank spreadsheets used by all LINXII investigators - Original templates provided for sites to input their own data

 Hall,R.O., Tank,J.L., Sobota,D.J., Mulholland,P.J., O'Brien,J.M., Dodds,W.K., Webster,J.R., Valett,H.M., Poole,G.C., Peterson,B.J., Meyer,J.L., McDowell,W.H., Johnson,S. L., Hamilton,S., Grimm,N., Gregory,S.V., Dahm,C., Cooper,L., Ashkenas,L.R., others 2009, Nitrate removal in stream ecosystems measured by 15N addition experiments: total uptake (Pub. No: 4389)
 Mulholland, Patrick J., Hall, Robert O., Jr., Sobota, Daniel J., Dodds, Walter K., Findlay, Stuart E. G., Grimm, Nancy B., Hamilton, Stephen K., McDowell, William H., O'Brien, Jonathan M., Tank, Jennifer L., Ashkenas, Linda R., Cooper, Lee W., others 2009, Nitrate removal in stream ecosystems measured by 15N addition experiments: denitrification (Pub. No: 4390)