Arctic LTER Database

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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.

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Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data
Dataset ID:2012_GS_ITEX_CH_SoilData.04
Dataset Title:Summary of soil temperature, moisture, and thaw depth for 14 chamber flux measurements sampled near LTER shrub sites at Toolik Field Station, Alaska, summer 2012.
Investigator 1: 
First Name:Gaius
Last Name:Shaver
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 2: 
First Name:Edward
Last Name:Rastetter
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 3: 
First Name:Mathew
Last Name:Williams
Organization:University of Edinburgh
Address line 2:School of Geosciences
City:Edinburgh
State:
Zip Code:EH9 EJU
Country:United Kingdom
Investigator 4: 
First Name:James
Last Name:Laundre
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
Zip Code:02543
Country:United States
Investigator 5: 
First Name:Laura
Last Name:van der Pol
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Associate Investigators:
Keywords:photosynthesis; shrub canopy, chamber flux measurement; soil temperature, soil moisture, volumetric water content
Abstract:Soil temperature at 5cm and 10cm depth [C], volumetric water content (VWC) [%] and depth of thaw [cm] for 14 shrub canopy flux plots measured in vicinity of the Toolik Field Station, AK in 2012.
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.10152&urlTail=terrest/tracegas/data/2012_GS_ITEX_CH_SoilData.csv
Data File Name 2012_GS_ITEX_CH_SoilData
Beginning Date 6/23/2012
End Date 8/7/2012
Number of Data Records 18
Other Files to Reference 2012_GS_ITEX_BF3_DiffuseLightData; 012_GS_ITEX_CH_SoilData; 2012_GS_ITEX_CHFluxData; 2012_GS_ITEX_LC_ParameterSummary; 2012_GS_ITEX_MaxCanopyHeight; 2012_GS_ITEX_PercentCover; 2012_GS_ITEX_CHN_Data; 2012_GS_ITEX_PF_LAISummary; 2012_GS_ITEX_RawPinDrop_Data; 2012_GS_ITEX_ShootACiData; 2012_GS_ITEX_ShootHarvestData; 2012_GS_ITEX_ShrubCanopy_DailyLogger; 2012_GS_ITEX_InstantLogger; 2012_GS_ITEX_SunScan_LAI; 2012_GS_ITEX_SunScan_PAR; 2012_GS_PFandCH_GPS; 2012_GS_ITEX_PF_ShootLightCurve; 2003-2004gsfluxleafN; 2003-2009gscurveparameters; 2003-2009gsflux; 2003-2009gsGPSandveg; 2003-2009gsharvestLAI-N; 2003-2009gsspecieslist; 2004-2009gscoverft; 2004-2009gscoversp;
Availability Status 1
Quality Control Information Soil temperature probe calibration was checked at the start of the field season by placing probes into a ice water bath to ensure they read 0-deg Celsius. Soil moisture (VWC) was corrected for arctic tundra soil using a calibration developed by J. Powers in 2003.
Maintenance Description This was a season-long project | though it followed similar methods to ITEX projects performed starting in 2003 that are likely to be replicated in the future for reasearch at the Toolik Field Station | AK.
Log of Changes: Version 2: Missing values changed to #N/A. CH 28Jan2013
Version 3: Updated metadata to new form (with sites sheet). CH April 2013.
Version 4: Corrected the extension of the eml Excel file - it was saved as .xls instead of .xlsx JimL 17May13
 
RESEARCH LOCATION:                  
Location Name LTER Shrub Block 1 LTER Shrub Block 2 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 Upland site; co-located in Block 1 of the Shrub LTER sites; IVO 68 38'18.8" N | 149 34' 07.2" W +/- 50m. Except for plots marked "FERT" | plots are outside of the designated LTER treatments | though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. Outlet site; co-located in Block 2 of the Shrub LTER sites; IVO 68 38'008.1" N | 149 35' 017.1" W +/- 50m. Except for plots marked "FERT" | plots are outside of the designated LTER treatments | though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. 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 68.6385555555555 68.6355833333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.568666666666 -149.588083333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation 747 m 730 m In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map View on Google Map              
                   
 
TAXONOMIC COVERAGE:
Organisms studied Betula nana; Salix pulchra; Salix glauca
 
Methods:CHAMBER FLUX MEASUREMENTS
CO2 and H2O fluxes were measured using a Licor 6400 photosynthesis system (Li-Cor Inc., Lincoln, Nebraska, USA) connected to a 1m x 1m plexiglass chamber in canopies dominated either by Salix pulchra or Betula nana shrub species. The height of the chamber varied depending on the height of the canopy being measured; chamber bases were constructed of PVC pipe to accomodate canopies with heights up to 125 cm. In addition to the plexiglass chamber, we also constructed a plexiglass "sleeve" that could extend the height of the rigid portion of the chamber by 0.25m.

To set up each chamber, a location was chosen where the base would be level enough to ensure a complete seal with the plexiglass chamber and shrub branches could be moved either in or out of the chamber without creating large gaps in the canopy inside the chamber. Branches were included within the chamber if they were rooted within the chamber and excluded otherwise. Once the base was in place, we drove hollow PVC pipe legs into the permafrost and inserted an aluminum frame with foam campermount tape along the top edge for the plexiglass chamber and/or sleeve to rest upon, creating an airtight seal. The aluminum frame had taped to it semi-transparent, plastic skirt which extended to the ground (+30cm). We sealed the skirt to the tundra by weighting the skirt with heavy chains, pushing them firmly into the moss layer where possible and adding additional plastic materials as needed to ensure a good seal. We screwed the LiCor custom chamber head attachment over the holes drilled into the plexiglass chamber, again sealing with a rubber gasket. The air in the chamber was mixed using 4-8 small fans (depending on chamber height) powered by a 12v battery.

At each plot we took measurements to create two light curves: one under direct light and one under diffuse light conditions. In order to determine the fraction of diffuse light, we used a DeltaT Beam Fraction Sensor (BF3, Delta-T Devices Ltd, Burwell Cambridge, UK) which quantifies the total irradianc and total diffuse light from which the diffuse light fraction (diffuse light/total light) can be calculated. For each day of flux measurements, the BF3 logged an instantaneous reading every 30-60 seconds set up on a leveled tripod at approximately 2 m above the ground. For the purpose of correlating the diffuse light fraction with each flux measurement, the LiCor 6400 and BF3 sensor were synchronized to read the same time (+/- 1 sec) at the start of each day.

Different light levels for both diffuse and direct light curves were achieved by taking measurements under a variety of conditions: ambient light (no manipulation), successive shading levels (covering the chamber with 1-5 fine mesh net cloths), and intercepting direct light with photographic diffuser panels, as well as reflecting light into the chamber to increase the amount of diffuse light with white photographic panels. When the diffuser panels were used, they were carefully positioned to intercept all direct light that would otherwise enter the chamber. Whenwhite reflector panels were used, they were positioned on the side of the chamber opposite the sun and angled towards the chamber so as to increase the amount of diffuse light entering the chamber (these were used in conjuction with the diffuser panels). For these 'artificial' diffuse light measurements, we did not diffuse the BF3 sensor, thus the diffuse fraction calculations during these flux measurements do not represent the light conditions in the chamber. After field tests of using the diffuser and reflector panels, we determined that the panels effectively block all direct light, and thus we assume the diffuse light fraction is greater than 0.7 for these measurements. At each light level a flux measurement lasted 45 - 60 secs in total, with CO2 and H2O concentrations in the chamber recorded by the LiCor 6400 every 2 secs. After each measurement we lifted the chamber until CO2 and H2O concentrations had stabilized at ambient levels. We made an effort to obtain a wide range of flux measurements for light levels between 0-1600, and used whatever chamber light treatments were needed to achieve that based on the ambient light conditions.

In addition to light measurements, we made at least three measurements in the dark for each day we took flux measurements. These were achieved by covering the chamber in an opaque tarpaulin cloth. These measurements represent the ecosystem respiration.

After each light curve we determined chamber volume by taking depth measurements from the top of the chamber base to the ground. We measured the chamber base depth with 36 measurements made at regular 20cm intervals determined by placing a 1m x1m plastic frame with a 20cm x 20cm string grid on top of the base. The volume determined by these depth measurements (chamber surface area*average depth) was added to the volume of the plexiglass chamber (and sleeve, as needed) . The surface area of the inside of the 1 m x 1 m plexiglass chamber was 0.8836m2.

SOIL DATA MEASUREMENTS
After taking the volume measurements of the chamber base, we characterized the soil conditions within the chamber by measuring the soil temperature, soil moisture, and thaw depth at six different locations central to the 1m x 1m chamber flux plot.

The soil temperature was measured at 5cm and 10cm below the soil surface at using traceable soil temperature probes (Fischer Scientific). Temperatures were recorded once the thermometer reading was stable for at least 30 seconds. On occasions when flux measurements spanned multiple days, soil temperature measurements were taken on each day, though measurements were made on the perimeter of the flux chamber base so to minimize the disturbance to the soil and vegetation until all flux measurements were complete.

Volumetric water content (VWC) was measured to estimate percent soil moisture using a Hydrosense Water Content Sensor (TDR probe) with 12cm tines (Campbell Scientific). The tines were inserted into the soil at a 45-degree angle for instantaneous readings. If the soil was too rocky to penetrate to the desired depth for any measurement this is indicated in the notes column. The VWC values were corrected for arctic tundra soils using a calculation developed by J. Powers in 2003 [see below]. Both original and corrected values are listed in the data sheet.

Thaw depth measurements were made using a 110 cm thaw depth probe marked every 0.5 cm. The probe was inserted into the ground as far as possible, and the depth from the tip of the probe to the soil's surface, considered to be the depth where no green moss or vegetation was visible.

CALCULATIONS:
The TDR probe is calibrated at manufacture for use in agricultural soils; for tundra soils meter readings are corrected using the equation:

actual VWC (%) = 0.5952(meter reading) + 7.684
R2 = 0.8649

(J Powers 2003)




Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
YEAR year of measurement datetime   YYYY   #N/A=Missing or Not Measured
DATE date of measurement datetime   DD-MMM-YY   #N/A=Missing or Not Measured
SITE Toolik text     #N/A=Missing or Not Measured
GROUP Measurement location in relation to Toolik Lake LTER Shrub plots; In vicinity of Block1 =Upland, IVO Block 2 =Outlet text     #N/A=Missing or Not Measured
PLOT Individual plot identifier text       #N/A=Missing or Not Measured
TREAT none or fertilised annually (FERT) (with N and P) text     #N/A=Missing or Not Measured
PHASE Measurement series (round of measurements within each year) ; Not used in this dataset number number     #N/A=Missing or Not Measured
PLOT SIZE 1m x 1m chamber size text       #N/A=Missing or Not Measured
TIME time of measurement; not used in this dataset datetime   HH24:Mi:SS   #N/A=Missing or Not Measured
td_1 replicate 1 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_2 replicate 2 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_3 replicate 3 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_4 replicate 4 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_5 replicate 5 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_6 replicate 6 of thaw depth number centimeter     #N/A=Missing or Not Measured
td_mean mean of thaw depth number centimeter     #N/A=Missing or Not Measured
temp5_1 replicate 1 of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_2 replicate 2 of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_3 replicate 3 of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_4 replicate 4of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_5 replicate 5 of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_6 replicate 6 of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp5_mean mean of soil temperature at 5 cm number celsius     #N/A=Missing or Not Measured
temp10_1 replicate 1 of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_2 replicate 2 of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_3 replicate 3 of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_4 replicate 4of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_5 replicate 5 of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_6 replicate 6 of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
temp10_mean mean of soil temperature at 10 cm number celsius     #N/A=Missing or Not Measured
VWC reading _1 replicate 1 of VWC number percent     #N/A=Missing or Not Measured
VWC reading_2 replicate 2 of VWC number percent     #N/A=Missing or Not Measured
VWC reading_3 replicate 3 of VWC number percent     #N/A=Missing or Not Measured
VWC reading_4 replicate 4 of VWC number percent     #N/A=Missing or Not Measured
VWC reading_5 replicate 5 of VWC number percent     #N/A=Missing or Not Measured
VWC reading _6 replicate 6 of VWC number percent     #N/A=Missing or Not Measured
VWCreading _mean mean of VWC number percent     #N/A=Missing or Not Measured
VWC corrected _1 replicate 1 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected_2 replicate 2 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected_3 replicate 3 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected_4 replicate 4 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected_5 replicate 5 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected _6 replicate 6 of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
VWC corrected _mean mean of corrected (see calculations below) VWC number percent     #N/A=Missing or Not Measured
Surface temp_1 replicate 1 of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
Surface temp_2 replicate 2 of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
Surface temp_3 replicate 3 of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
Surface temp_4 replicate 4 of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
Surface temp_5 replicate 5 of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
Surface temp_6 replicate 6 of surface temperature number celsius     #N/A=Missing or Not Measured
Surface temp_mean mean of surface temperature; Not used in this dataset number celsius     #N/A=Missing or Not Measured
DOM VEG Dominant canopy vegetation text       #N/A=Missing or Not Measured
COMMENTS additional notes text