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Conditions of Use

The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes. The Data User is permitted to produce and distribute derived works from this dataset provided that they are released under the same license terms as those accompanying this Data Set. Any other uses for the Data Set or its derived products will require explicit permission from the dataset owner.
2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

5 ) Notification. The Data User will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The Data User will provide the data contact with two reprints of any publications resulting from use of the Data Set and will provide copies, or on-line access to, any derived digital products. Notification will include an explanation of how the Data Set was used to produce the derived work.
6 ) Collaboration. The Data Set has been released in the spirit of open scientific collaboration. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.


While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data, Dataset via LTER Data Portal
Dataset ID:2008_CO2_Flux_Welker.03
Dataset Title:Welker IPY snow shrub 2008 flux data, Toolik, Alaska.
Investigator 1: 
First Name:Jeff
Last Name:Welker
Organization:Ecosystem/Biomedical Lab
Address line 2:University of Alaska
Address line 3:
Zip Code:99508
Investigator 2: 
First Name:Paddy
Last Name:Sullivan
Organization:Ecosystem/Biomedical Lab
Address line 2:University of Alaska
Zip Code:99508
Associate Investigators:
Keywords:snow fences, carbon dioxide fluxes, net ecosystem exchange, ecosystem respiration, productivity, disturbance
Abstract:This is a study of how different snow regimes effect CO2 exchange in tussock tundra and whether there are shifts in ecosystem C cycling when facets of "drift" effects are isolated. The study is part of the IPY program and is aimed at measuring the state of Arctic tundra.
For questions about the Metadata and data contact the Investigators.
For information about this web site contact:
Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Online URL:
Data File URL
Data File Name 2008_CO2_Flux_Welker.csv
Beginning Date 6/8/2008
End Date 8/14/2008
Number of Data Records 534
Other Files to Reference
Availability Status
Quality Control Information
Maintenance Description
Log of Changes: Version 1 : Mar 2011 Received file from Jeff Welker. Updated the metadata sheet and created eml files and web files. JimL
Version 2: Corrected Distrubution URL. It had xlsfiles in the path. Jim L 19Jun14
Version 3: Changed Distrubution URL since the LTER network DAS system is being discontinued. JimL 9Apr2015
RESEARCH LOCATION:                  
Location Name Toolik River IPY Welker Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One  
Geographic Description Four locations on the eastern side of the Toolik River where by snow fences were established as part of IPY near Toolik Lake on the North Slope of Alaska Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description  
Location Bounding Box                  
West Bounding Coordinate                  
East Bounding Coordinate                  
North Bounding Coordinate                  
South Bounding Coordinate                  
OR if single point location                  
Latitude 68.623608 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.5712167 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation 764 m In Meters In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map                
Organisms studied
Methods: This is CO2 flux data, NEE and Re, from four locations on the eastern side of the Toolik River where by snow fences were established as part of IPY. We measured CO2 excange during the summer of 2007 multiple times and at 3 locations (3 replicates) with four treatments, control, drift, drift and shoveled and drift, shoveled and watered ( C, D, DS, DSW). The three replicates were called: upper, south, north (U, S, N).

During the snow-free growing season (June-August), ecosystem CO2 fluxes were measured using a clear plexiglass chamber (0.5 x 0.5 x 0.40 cm). Net ecosystem exchange (NEE) and ecosystem respiration (ER) measurements were made at mid-day in tussock and intertussock location. CO2 concentration, temperature and humidity within the chamber were monitored using a LI-6200 portable photosynthesis system (LI-COR Biosciences, Lincoln, NE). The chamber was fitted with two small fans and a sensor to measure photosynthetic photon flux density (PPFD). The chamber was vented to the atmosphere between measurements until [CO2] returned to ambient levels. CO2 exchange rates during the clear and dark chamber measurements were calculated following Hooper et al. (2002). Photosynthesis is presented as a positive flux and respiration as a negative flux in this study. Therefore, gross ecosystem photosynthesis (GEP) was determined by subtracting ER (dark chamber) from NEE (clear chamber).

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
Block Block-these are the locations of the set of treatments-one block consist of all four snow treatments: upper,south, north text        
Treatment Treatment-these are the four different snow mannipulaiton treatments, C = control where now fence was put up, D = a drift treatment which is behind the snow fence (1 m x 15 m), DS = the drift plus shoveling which involved snow removal before melt and drift, DSW = plus shoveling plus added water after melt. text        
date Date is the calender day of flux measurements datetime   dd-mmm-yyyy    
plot Plot is the subsamples within a treatment: A, B, C text        
type Type is measurments: iT= in between tussocks or T = on tussocks text        
measurement measurements are: NEE-net ecosystem CO2 exchange and Re = ecosystem respiratiaon measured with covered chamber text        
flux flux is the rate of CO2 exchange number micromolePerMeterSquaredPerSecond     .=Missing or Not Measured

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