Arctic LTER Database

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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 http://ecosystems.mbl.edu/arc/terrest/biomass/index.shtml

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.
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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 ID:	1994gsbflx.6
Dataset Title:	Ecosystem-level Carbon dioxide fluxes in two long-term experimental wet sedge tundra sites near Toolik Lake, AK, ARC LTER 1994.
Investigator 1:
First Name:	Gus
Last Name:	Shaver
Organization:	Marine Biological Lab
Address line 2:	7 MBL St.
Address line 3:
City:	Woods Hole
State:	MA
Zip Code:	02543
Country:	USA
Investigator 2:
First Name:	Jim
Last Name:	Laundre
Organization:	Marine Biological Lab
Address line 2:	8 MBL St.
City:	Woods Hole
State:	MA
Zip Code:	02544
Country:	USA
Associate Investigators:
Keywords:	Alaska, biomass, Carbon dioxide flux, respiration, productivity, nitrogen, phosphorus, tundra.
Abstract:	Ecosystem-level Carbon dioxide fluxes were measured in two long-term experimental wet sedge tundra sites near Toolik Lake, AK. Experimental treatments at each site included factorial NxP, greenhouse and shade house and were begun in 1985 (Sag site) or in 1988 (Toolik sites). Fluxes were measured on quadrats that were later sampled for biomass and leaf area.
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 Email: arc_im@mbl.edu Online URL: http://ecosystems.mbl.edu/ARC/
DATA FILE INFORMATION:
Data File URL	http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.1380&urlTail=terrest/biomass/data/1994gsbflx.csv
Data File Name	1994gsbflx
Beginning Date	7/24/1994
End Date	7/27/1994
Number of Data Records	42
Other Files to Reference
Availability Status
Quality Control Information
Maintenance Description
Log of Changes:	15Mar95 Separated comma delimited data from Excel file. JL 28Oct2004 Added units and precision to variable description section. JL
	Version2: Creaded Excel metadata form. Changed title and added attribut table. 10Jan06 JimL
	Version 3: Added LTERNET Data Access server proxy for Excel and comma delimited data files.
	Version 4: Upadte LTERNET Data Access server proxy link for Excel and comma delimited data files. Changed from knb to das in url.
	Version 5: Updated the metadata form to new version and eml to 2.1.0 JimL 9Jul2012
	Version 6: Updated metadata to newer form (with sites sheet). Ch March 2013.

RESEARCH LOCATION:

Location Name

Toolik

Sagavanirktok River

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Geographic Description

Toolik Lake(68 degrees 38'N, 149 degrees 34'W, elevation 760 m) (68 degrees 38N, 149 degrees 34W) North Slope, Alaska, U.S.A.

Sagavanirktok River (68 degrees 46'N, 148 degrees 52'W, elevation 470 m) North Slope, Alaska, U.S.A.

Enter Description

Location Bounding Box

West Bounding Coordinate

East Bounding Coordinate

North Bounding Coordinate

South Bounding Coordinate

OR if single point location

Latitude

68.6333333333333

68.7666666666667

In Decimal Degrees

Longitude

-149.566666666667

-148.866666666667

In Decimal Degrees

Elevation

760

470

In Meters

Link to Google Map

View on Google Map


TAXONOMIC COVERAGE:
Organisms studied

Methods:	Plots were setup as indicated below, with annual fertilization treatments of 10 g/m2 Nitrogen (as NH4NO3) and 5 g/m2 Phosphorous (as triple superphosphate). Greenhouses and shadehouses were annually set up in late May or early June and removed in the end of August or early September. Sites: Block 1 - Toolik Inlet (CT, N, P, NP, GH, GHNP, and Shade treatment codes) Indicated as "Block 1" Treatments began summer of 1989; one 5x10m plot/treatment Block 2 - Toolik Outlet (Same treatments) "Block 2" Treatments began summer of 1989; one 5x10m plot/treatment Calculations: Units: Tissue mass data are expressed in g/quadrat (400 cm2). Multiply by 25 to get g/m2. Leaf blade area is in cm2/quadrat. Multiply by .0025 to get m2 leaf/m2 ground. Sampling Description. Biomass quadrats, size 20x20 cm, were randomly located along line transects within plots. There were 4 quadrats/plot (treatment) collected in Blocks 1 and 2. All aboveground biomass plus belowground stems and rhizomes were clipped in 20x20 cm quadrats. Ecosystem-level CO2 fluxes were measured on 3 of the 4 quadrats using a LiCor 6200 Portable Photosynthesis System. A custom-made clear Plexiglas cuvette (30x30 cm surface area x 30 cm high) was placed directly over the quadrat to be sampled using the standing surface water as a seal. A standard depth was used to keep the chamber volume constant. After allowing the LiCor system to stabilize for a few seconds, 10 consecutive observations of the average CO2 flux over 20 second intervals were made. The last 6 of the 10 observations were then averaged for use as the flux measurement. Air temperature, photosynthetically active photon flux, and CO2 concentration inside the cuvette were also recorded with each observation. All flux measurements were made on a warm sunny day (26 July 1994) between 11:00 AM and 3 PM Alaska Daylight time. The cuvette was then removed briefly to allow air temperatures and CO2 concentrations to recover before being shaded with an opaque blanket for ecosystem respriation. During the unshaded measurements photon flux inside the cuvette varied from 600-2000 microE m-2 sec-1, but most measurements were made between 950-1200 micro E m-2 sec-1. Photon flux during the unshaded measurements were always less than 10 micro E m-2 sec-1, usually zero. Air temperatures were between 18o and 28o C, with most measurements made between 20o and 24o C. Concentration of CO2 inside the cuvette was 330-440 ppm, with most measurements made at 340-350 ppm. In presenting our results, we use the unshaded (full sunlight) CO2 flux measurement as our measure of Net Ecosystem Production, or NEP. Ecosystem Respiration, or RE, is the measurement made in the darkened cuvette. Gross Ecosystem Production (=Gross Ecosystem Photosynthesis), or GEP, is the difference between NEP and RE. In this presentation, negative values represent CO2 losses to the atmosphere (RE is always negative), and positive values represent CO2 inputs (GEP is always positive). See 1994gswsbm.txt for information on the biomass collection.

Data Table

Variable Name	Variable Description	Data Type	Units	DateTime Format	Code Information	Missing Value Code
Label	Quadrat label - First two characters= block number. Next characters = treatment code + rep. no.	text
Leaf Area	Leaf area	number	centimeterSquaredPerFourHundredthMeterSquared
LAIm2_m2	Leaf area in m2/m2 (leaf area * (10,000/400)/10,000)	number	meterSquaredPerMeterSquared
IPAR	Avg QNTM * (1-e^(-0.8*Leaf Area))	number	dimensionless
Blade wt	Weight of leaf blade	number	gram
Leaf_culm wt	Ratio of leaf blade wt to culm wt	number	dimensionless
Above wt	Total aboveground plant biomass	number	gram
Total wt	Total biomass	number	gram
Above(vasc)	Biomass of vascular plants	number	gram
NEP	Net Ecosystem Production - full sunlight CO2 flux	number	micromolePerMeterSquaredPerSecond
Resp	Ecosystem Respiration - darken CO2 flux	number	micromolePerMeterSquaredPerSecond
GEP	Gross Ecosystem Production - (NEP - Resp)	number	micromolePerMeterSquaredPerSecond
Avg QNTM	Average photon flux inside the cuvette	number	micromolePerMeterSquaredPerSecond
Avg TAIR	Average air temperature inside the cuvette	number	celsius
Avg CO2	Average CO2 concentration inside the cuvette	number	partPerMillion