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Eight Mile Lake Research Watershed, Thaw Gradient, The radiocarbon value of ecosystem respiration, 2004-2021 I: Reco

General Information
Data Package:
Local Identifier:knb-lter-bnz.512.11
Title:Eight Mile Lake Research Watershed, Thaw Gradient, The radiocarbon value of ecosystem respiration, 2004-2021 I: Reco
Alternate Identifier:DOI PLACE HOLDER
Abstract:

In this larger study, we are asking the question: Is old carbon that comprises the bulk of the soil organic matter pool released in response to thawing of permafrost? We are answering this question by using a combination of field and laboratory experiments to measure radiocarbon isotope ratios in soil organic matter, soil respiration, and dissolved organic carbon, in tundra ecosystems. The objective of these proposed measurements is to develop a mechanistic understanding of the SOM sources contributing to C losses following permafrost thawing. We are making these measurements at an established tundra field site near Healy, Alaska in the foothills of the Alaska Range. Field measurements center on a natural experiment where permafrost has been observed to warm and thaw over the past several decades. This area represents a gradient of sites each with a different degree of change due to permafrost thawing. As such, this area is unique for addressing questions at the time and spatial scales relevant for change in arctic ecosystems. This data set includes the growing season radiocarbon values of ecosystem and plant respiration at the thaw gradient and CiPEHR (a permafrost warming experiment). Depending on the year, the measurements were taken monthly during the growing season or just once a growing season.

Short Name:knb-lter-bnz.512.11
Publication Date:2022-12-06
For more information:
Visit: http://www.lter.uaf.edu/data/data-detail/id/512
Visit: DOI PLACE HOLDER

Time Period
Begin:
2003-06-01
End:
2021-09-01

People and Organizations
Contact:Data Manager (Bonanza Creek LTER) [  email ]
Creator:Ebert, Chris H 
Creator:Pegoraro, Elaine 
Creator:Hicks-Pries, Caitlin Elizabeth 
Creator:Mauritz, Marguerite (Research Associate Professor)
Creator:Natali, Susan (Affiliate Scientist)
Creator:Schuur, Edward (Senior Investigator)
Organization:Bonanza Creek LTER

Data Entities
Data Table Name:
512_EML_Radiocarbon_GradientReco_2021.csv
Description:
Eight Mile Lake Research Watershed, Thaw Gradient, The radiocarbon value of ecosystem respiration
Detailed Metadata

Data Entities

Data Table

Data:https://pasta-s.lternet.edu/package/data/eml/knb-lter-bnz/512/11/ad6d09cbaba1d1258f7bf55a9520c763
Name:512_EML_Radiocarbon_GradientReco_2021.csv
Description:Eight Mile Lake Research Watershed, Thaw Gradient, The radiocarbon value of ecosystem respiration
Number of Columns:13

Table Structure
Object Name:512_EML_Radiocarbon_GradientReco_2021.csv
Text Format:
Number of Header Lines:1
Record Delimiter:\n
Line Delimiter:\n
Orientation:column
Simple Delimited:
Field Delimiter:,

Table Column Descriptions
 MonthYearDateSiteSampleAtm_13CAtm_14CReco_13CTrap_13CTrap_14CFraction_airFraction_RecoReco_14C
Column Name:Month  
Year  
Date  
Site  
Sample  
Atm_13C  
Atm_14C  
Reco_13C  
Trap_13C  
Trap_14C  
Fraction_air  
Fraction_Reco  
Reco_14C  
Definition:The month sampels were takenThe year samples were takenThe year and month of samplingThe site from the permafrost thaw gradient where the samples were taken from (minimal, moderate, or extensive thaw)The individual chamber the sample was taken fromThe atmospheric value of ?13C (a mean of flask measurements taken at the field site fron 2003 through 2006)The atmospheric value of ?14C in the year the Reco samples were measured (from flasks or annual plant cellulose, see atm worksheet).Keeling plot values of Reco ?13C from the sample chambers. Keeling plots were performed in 2004, 2008, and 2009 only. For all other years, we used an overall average of the 2004, 2008, and 2009 values (-24.1).The ?13C from the molecular seive trap that collected the CO2 from the chamber. The ?14C from the molecular seive trap that collected the CO2 from the chamber. The fraction of atmospheric contamination in the molecular seive trap.The fraction of Reco in the molecular seive trap.The corrected value of Reco ?14C, corrected for the atmospheric contamination in the trap.
Storage Type:string  
string  
string  
string  
string  
float  
float  
float  
float  
float  
float  
float  
float  
Measurement Type:nominalnominalnominalnominalnominalratioratioratioratioratioratioratioratio
Measurement Values Domain:
DefinitionThe month sampels were taken
DefinitionThe year samples were taken
DefinitionThe year and month of sampling
DefinitionThe site from the permafrost thaw gradient where the samples were taken from (minimal, moderate, or extensive thaw)
Allowed Values and Definitions
Enumerated Domain 
Code Definition
CodeExT
DefinitionExtensive Thaw
Source
Code Definition
Code ModT
DefinitionModerate Thaw
Source
Code Definition
Code MinT
DefinitionMinimal thaw
Source
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Unitdimensionless
Typereal
Missing Value Code:                          
Accuracy Report:                          
Accuracy Assessment:                          
Coverage:                          
Methods:                          

Data Package Usage Rights

Data Use

This work has been produced as part of the Long Term Ecological Research Program and data users should adhere to the Data Use Agreement of the Long Term Ecological Research Network. The consumer of these data (“Data User” herein) has an ethical obligation to cite it appropriately in any publication that results from its use. The Data User should realize that these data may be actively used by others for ongoing research and that coordination may be necessary to prevent duplicate publication. The Data User is urged to contact the authors of these data if any questions about methodology or results occur. Where appropriate, the Data User is encouraged to consider collaboration or coauthorship with the authors. The Data User should realize that misinterpretation of data may occur if used out of context of the original study. While substantial efforts are made to ensure the accuracy of data and associated documentation, complete accuracy of data sets cannot be guaranteed. All data are made available “as is.” The Data User should be aware, however, that data are updated periodically and it is the responsibility of the Data User to check for new versions of the data. The data authors and the repository where these data were obtained shall not be liable for damages resulting from any use or misinterpretation of the data. Thank you.

Citation

It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User should 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(s), Year of Data Publication, Title of Dataset, Publisher, Dataset identifier, Dataset URL, Dataset DOI. For Example: Van Cleve, Keith; Chapin, F. Stuart; Ruess, Roger W. 2016. Bonanza Creek Experimental Forest: Hourly Temperature (sample, min, max) at 50 cm and 150 cm from 1988 to Present, Bonanza Creek LTER - University of Alaska Fairbanks. BNZ:1, http://www.lter.uaf.edu/data/data-detail/id/1. doi:10.6073/pasta/725db90d86686be13e6d6b2da5d61217.

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 are provided by the Bonanza Creek LTER, a partnership between the University of Alaska Fairbanks, and the U.S. Forest Service. Significant funding for collection of these data was provided by the National Science Foundation Long-Term Ecological Research program (NSF Grant numbers DEB-1636476, DEB-1026415, DEB-0620579, DEB-0423442, DEB-0080609, DEB-9810217, DEB-9211769, DEB-8702629) and by the USDA Forest Service, Pacific Northwest Research Station (Agreement # RJVA-PNW-01-JV-11261952-231).

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.

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.

Disclaimer

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 in its present condition. 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.

Keywords

By Thesaurus:
Biogeochemistrycarbon, ecosystem respiration, radiocarbon, permafrost, tundra

Methods and Protocols

These methods, instrumentation and/or protocols apply to all data in this dataset:

Methods and protocols used in the collection of this data package
Description:

Experimental Design

The study site at the Eight Mile Lake watershed is located in the northern foothills of the Alaska Range. Permafrost temperature has been monitored annually on a gentle north-facing slope at this site, in a 30 m deep borehole that was installed in 1985 before the permafrost started to thaw. While permafrost thaw can sometimes result in water ponding depending on local topography, this landscape consists largely of relatively well-drained uplands. In this watershed, we monitored three sites that represented differing amounts of change as a result of permafrost thaw based on observations of ground subsidence and depth of thaw. Our minimal thaw site had the shallowest summer thaw depth and the least ground surface subsidence, and the vegetation was typical moist acidic tundra, dominated by the tussock-forming sedge, Eriophorum vaginatum, with coexisting deciduous and evergreen shrubs, and an understory of mosses and lichens. A second site, located adjacent to the borehole, had moderate summer thaw depths and increased ground subsidence. Here the vegetation composition was similar to our minimal thaw site, but with increased biomass of all plant groups. Lastly, an extensive thaw site was located in an area where permafrost degradation had occurred at least several decades prior to the establishment of the borehole; thermokarst can already be observed in air photos of the area taken in 1954. This site had the deepest summer thaw depth and the most ground subsidence, and the plant biomass has shifted to dominance by shrubs, including blueberry (Vaccinium uliginosum) and cloudberry (Rubus chamaemorus), at the expense of sedges. Four radiocarbon measurements were collected from each site, but for some years, only three were run for radiocarbon.

Methods

FIELD: To measure the Delta14C of Reco, we installed PVC collars (25.4 cm diameter x 10 cm deep; 12 at the thaw gradient, 4 per site, and 24 at CiPEHR, 6 per treatment) 8 cm into the soil. 10L dark chambers were fit onto the PVC collars encompassing the aboveground plant biomass. Ecosystem respiration ?14C was collected by pumping CO2 through a molecular sieve for 15 minutes. Prior to the collection, the chamber headspace was scrubbed for 45 minutes with soda lime while maintaining ambient pCO2 to reduce atmospheric contamination. During 2004, 2008, and 2009 at the thaw gradient and 2009, 2010, and 2011 at CiPEHR, we also measured delta13C using Keeling plots. Sampling only occurred under calm conditions. Plant respiration samples were taken from 20 x 20 cm areas (or 2, 10 x 10 cm areas that were combined for CiPEHR) and were separated into aboveground and belowground components. The aboveground plant parts (stems, leaves, flowers, fruits) were clipped at the soil surface and put into foil-covered half pint mason jars. Roots were collected down to the frozen soil and were rinsed twice and shaken dry before being put into separate mason jars. The headspace of the mason jars was scrubbed with soda lime and then the samples were incubated for 4 hours. At the end of 4 hours the headspace was pumped through molecular seive traps to collect the CO2 for 14C analysis. LAB: The molecular sieves were baked at 625degC to desorb CO2, which was purified using liquid N2 on a vacuum line and reduced to graphite by Fe reduction in H2. The graphite was sent to the UC Irvine W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (AMS) Laboratory for radiocarbon analysis.

Sampling Area and Study Extent
Sampling Description:

Sampling Frequency

monthly or annual

Sampling Extent:
Sampling Site: 
Description:EML -- Tussock tundra at treeline with permafrost thaw and thermokarst. This site is in the Eight Mile Lake Watershed, west of the town of Healy on Stampede Road, Interior Alaska. This area contains three sites on a permafrost thaw gradient and a nearby experimental snow fence manipulation.. Site alternate names:
Site Coordinates:
Longitude (degree): -149.239569Latitude (degree): 63.880708

Time Period
Begin:
2003-06-01
End:
2021-09-01

People and Organizations

Publishers:
Organization:Environmental Data Initiative
Email Address:
info@edirepository.org
Web Address:
https://edirepository.org
Id:https://ror.org/0330j0z60
Creators:
Individual: Chris H Ebert
Address:
Center for Ecosystem Science and Society, POBox 5620,
Flagstaff, AZ 86011 United States
Phone:
952-297-4567 (voice)
Email Address:
christopher.ebert@nau.edu
Web Address:
https://www2.nau.edu/schuurlab-p/
Individual: Elaine Pegoraro
Email Address:
elainepegoraro@lbl.gov
Individual: Caitlin Elizabeth Hicks-Pries
Address:
Building 084, Room 0103D, Lawrence Berkeley National Lab,
Berkeley , CA 94720 United States
Phone:
510-495-8046 (voice)
Email Address:
cehpries@lbl.gov
Individual: Marguerite Mauritz
Position:Research Associate Professor
Address:
University of Texas, El Paso, 500 W University,
El Paso, TX 79902 United States
Email Address:
memauritz@utep.edu
Web Address:
https://expertise.utep.edu/profiles/memauritz
Individual: Susan Natali
Position:Affiliate Scientist
Address:
Woodwell Climate Research Center, 149 Woods Hole Road,
Falmouth, MA 02540 United States
Phone:
508-444-1560 (voice)
Email Address:
snatali@whrc.org
Web Address:
http://www.whrc.org/about/cvs/snatali.html
Individual: Edward Schuur
Position:Senior Investigator
Address:
Northern Arizona University: Ecosystem Science and Society Center (ECOSS) PO Box 5620,
Flagstaff, AZ 86011 United States
Phone:
(928) 523-8344 (voice)
Email Address:
Ted.Schuur@nau.edu
Web Address:
https://www2.nau.edu/schuurlab-p/
Organization:Bonanza Creek LTER
Address:
Boreal Ecology Cooperative Research Unit ,
University of Alaska Fairbanks,
P.O. Box 756780 ,
Fairbanks, AK 99775 USA
Phone:
907-474-6364 (voice)
Phone:
907-474-6251 (fax)
Email Address:
uaf-bnz-im-team@alaska.edu
Web Address:
http://www.lter.uaf.edu
Contacts:
Organization:Bonanza Creek LTER
Position:Data Manager
Address:
Boreal Ecology Cooperative Research Unit ,
University of Alaska Fairbanks,
P.O. Box 756780 ,
Fairbanks, AK 99775 USA
Phone:
907-474-6364 (voice)
Phone:
907-474-6251 (fax)
Email Address:
uaf-bnz-im-team@alaska.edu
Web Address:
http://www.lter.uaf.edu
Metadata Providers:
Organization:Bonanza Creek LTER
Position:Data Manager
Address:
Boreal Ecology Cooperative Research Unit ,
University of Alaska Fairbanks,
P.O. Box 756780 ,
Fairbanks, AK 99775 USA
Phone:
907-474-6364 (voice)
Phone:
907-474-6251 (fax)
Email Address:
uaf-bnz-im-team@alaska.edu
Web Address:
http://www.lter.uaf.edu

Temporal, Geographic and Taxonomic Coverage

Temporal, Geographic and/or Taxonomic information that applies to all data in this dataset:

Time Period
Begin:
2003-06-01
End:
2021-09-01
Sampling Site: 
Description:Dataset geographic description information is unavailable. {datafile/geoCoverage is empty}
Site Coordinates:
Longitude (degree): -149.2535833Latitude (degree): 63.87836111

Project

Parent Project Information:

Title:The Bonanza Creek LTER
Personnel:
Individual: Keith Van Cleve
Organization:Bonanza Creek LTER
Position:Lead Principal Investigator
Role:Principal Investigator
Individual: F.S. Stuart Chapin
Organization:Bonanza Creek LTER
Position:Lead Principal Investigator
Address:
Department of Biology and Wildlife; Institute of Arctic Biology: University of Alaska Fairbanks 193 Arctic Health P.O. Box 757000,
Fairbanks, AK 99775 United States
Phone:
(907) 455-6408 (voice)
Phone:
(907) 474-6967 (fax)
Email Address:
terry.chapin@alaska.edu
Web Address:
http://terrychapin.org/
Role:Principal Investigator
Individual: Roger W. Ruess
Organization:Bonanza Creek LTER
Position:Lead Principal Investigator
Address:
Institute of Arctic Biology University of Alaska Fairbanks P.O. Box 757000,
Fairbanks, AK 99775-0180 United States
Phone:
(907) 474-7153 (voice)
Phone:
(907) 474-6967 (fax)
Email Address:
rwruess@alaska.edu
Web Address:
http://www.iab.uaf.edu/~roger_ruess/
Role:Principal Investigator
Funding:

NSF Grant numbers DEB-1636476, DEB-1026415, DEB-0620579, DEB-0423442, DEB-0080609, DEB-9810217, DEB-9211769, DEB-8702629

USDA Forest Service, Pacific Northwest Research Station (Agreement # RJVA-PNW-01-JV-11261952-231)

Maintenance

Maintenance:
Description:

corrections

14C data were reported at the same delta13C value to correct for mass-dependent fractionation effects. The ecosystem respiration radiocarbon values from the trap were corrected for atmospheric contamination based on a simple 2-pool mixing model, which uses trap and atmospheric 13C and 14C values and ecosystem 13C values from keeling plots (see Schuur and Trumbore 2006 for details). An average of all keeling plot 13C values was used for ecosystem respiration when ecosystem respiration 13C was not measured. Plant respiration 14C was not corrected.

Status

Completed

Frequency:
Other Metadata

Additional Metadata

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