uid=ARC,o=lter,dc=ecoinformatics,dc=org all public read 2012_GS_ITEX_PF_ShootACiData.05 Arctic LTER Program Gaius Shaver

Ecosystems Center at the Marine Biological Laboratory 7 MBL Street Woods Hole MA 02543 United States

Arctic LTER Program

The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole MA 02543 USA

(508) 289 7496 arc_im@mbl.edu http://ecosystems.mbl.edu/ARC/ Edward Rastetter

Ecosystems Center at the Marine Biological Laboratory 7 MBL Street Woods Hole MA 02543 United States

Associated Researcher Mathew Williams

University of Edinburgh School of Geosciences Darwin Building Edinburgh EH9 EJU United Kingdom

Associated Researcher James Laundre

Ecosystems Center at the Marine Biological Laboratory 7 MBL Street Woods Hole MA 02543 United States

Data Manager Laura van der Pol

Ecosystems Center at the Marine Biological Laboratory 7 MBL Street Woods Hole MA 02543 United States

Field Crew 2012 A/Ci curve parameters and modeled carboxylation, electron transport, and triose-phosphate utilization efficiency rates from shoots clipped from low, mid, and the top of tall, shrub canopies dominated either by Salix pulchra or Betula nana species. Six shoots were harvested from each 1m x 1m plot, two from each level in the canopy. These plots were located near the LTER shrub plots at the Toolik Field Staion, AK for point frame measurements, and all measurements took place the summer of 2012. The species harvested were chosen based on the species present in each plot, thus the species from each segment of the canopy may not be the same. Additional information about each shoot can be found in the "PF_ShootLightcurve_Data" and "PF_ShootHarvest_Data" pages, regarding the light response curves, area, mass, leaf area index, and leaf nitrogen content of each shoot. The file "PF_PercentCover" contains the species cover data for each plot. shoot photosynthesis shrub canopy point frame A/Ci curve electron transport carboxylation efficiency Acceptance and utilization of LTER data requires that: The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions. The Principal Investigator of the data set be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications A copy of any resultant publications should be sent to: Principal Investigator Ecosystems Center Marine Biological Laboratory Woods Hole, MA 02543 http://ecosystems.mbl.edu/ARC/meta_template.php?FileName=./terrest/tracegas/xlsfiles/2012_GS_ITEX_PF_ShootACiData.html 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. -149.568666666666 -149.568666666666 68.6385555555555 68.6385555555555 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. -149.588083333333 -149.588083333333 68.6355833333333 68.6355833333333 2012-06-23 2012-08-07 Organisms Studied Genus Betula Species nana Genus Salix Species pulchra Genus Salix Species glauca 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. Version 2: Updated units to current standards. Missing values changed to #N/A. CH 28Jan2013 Version 3: Updated metadata to newer form (with sites sheet). CH April 2013. Version 4: Corrected eml excel file name wrong extension. JimL 16May13 Version 5: Corrected the upper/lower case of missing value JimL 17May13 Data Manager

The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole MA 02543 USA

(508) 289 7496 arc_im@mbl.edu http://ecosystems.mbl.edu/ARC/ ARC LTER

The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole MA 02543 USA

(508) 289 7496 arc_im@mbl.edu http://ecosystems.mbl.edu/ARC/ HARVEST METHOD: The methods for setting up each point frame plot are described below in the section titled "POINT FRAME PIN-DROP METHODS". The methods here describe how each shoot was harvested from the plots which were used for the point frame method. Six shoots were harvested from each of 19 1m x 1m point frame plots which were dominated either by Salix pulchra or Betula nana tall, shrub species. The "shoots" described here are branch clippings between eight to ten inches long. Whenever possible they were selected for appearing relatively healthy, intact leaves, and each shoot was taken from a different plant. As these shoots were used for shoot-level and leaf-level measurements, shoots with bi-furcated stems -- or two stems from the same branch/height were cut -- one for leaf-level and the second for shoot-level analyses. Before being cut, we measured the distance from the point frame to the highest tip on the shoot as well as the distance from the point frame to the shoot five inches from the tip. This way, we could approximate the angle of the shoot relative to the ground. Using the same criteria as for the pin-drop measurements, we measured the distance from the top of the shoot to the soil. In addition, the row number and pin-hole number nearest to the shoot's location with respect to the point frame was also recorded . We then measured the leaf area index (LAI) of the shoot by holding an LAI-2000 (Li-Cor Inc., Lincoln, Nebraska, USA) in the exact location where the shoot had been and taking the average of three readings (one above, three below). For these measurements we used the one-quarter cut out and took care to always hold the instrument level and with the technician's body casting a uniform shadow over the instrument's eye, with the technician standing between the instrument and the sun. On occasion when it was raining during the shoot harvest, the area near where the shoot had been was marked with flagging tape, and the the LAI measurement was taken at a later date, using the height from frame/distance from ground meausrements as well as the row number and pin hole measurements as a guide. Once cut, the shoot was placed immediately into water and transported to the lab. Once in the lab, the end of each shoot was clipped under water to ensure that there were no air bubbles in the stem that would inhibit the flow of water. Shoots were then allowed to sit at ambient room conditions (~20-25 degrees Celsius) until the the photosynthetic rates could be measured. A/Ci CURVE MEASUREMENT: The A/Ci curve measurements were taken using a Licor 6400 photosynthesis system (Li-Cor Inc., Lincoln, Nebraska, USA) with an opaque conifer chamber with red-blue-green (RGB) light source attachment (model number 6400-22L). The methods for setting up the LI-6400 are detailed in the ITEX Manual as updated in 2011 as are the procedures for correcting and modeling the A/Ci data. Each shoot was oriented in the chamber so that the leaves were facing the RGB light source. Care was taken to ensure that no leaves were caught between the foam gaskets. Aditionally, adhesive, mounting tack was used to ensure a seal around the end of the stem that protruded from the chamber and remained in water for the duration of measurements. The A/Ci curve measurements were conducted with the reference light level set to a constant 1500 umol PAR m-2 s-1. Each shoot was allowed to acclimate to the chamber conditions for 5-10 minutes or until the Ca:Ci ([CO2]amb to [CO2]internal to the cell) ratio was stable around ~0.7 +/- 0.1. The A/Ci curve measurements were taken at the following target chamber CO2 concentrations in the order listed (units are umol CO2): 400, 300, 200, 100, 50, 400, 500, 700, 900, 1300, 1500, 1700, 400. The shoot was given a minimum of 60 seconds but not more than 180 seconds to adjust to each new CO2 concentration before a measurement was taken, and the instrument matched the reference and sample chambers prior to every measurement. The block temperature of the infra-red gas analyzer (IRGA) was adjusted throughout the A/Ci measurement to maintain a leaf temperature as near as possible to 20 degrees Celsius. Once the measurment was complete, we took a light curve measurement, and then each shoot was carefully cut from the stem that remained outside the chamber so that only the portion of the shoot inside the chamber remained. This whole shoot was then photographed for later silhouette-area analysis with Image-J software [See "PF_ShootHarvest_Data" for details]. The leaves, stipules, petioles, green and brown stem, and other plant green organs were then clipped from the shoot, lain flat on a hinged, plexiglass folder, and scanned. These images were subsequently processed with the Image-J software to calculate the area of each tissue type; the sum of the area of the leaves, petioles, and stipules were used to correct the default area used when taking the light curve measurements. Each tissue type was separated, placed in a coin envelope, labeled, and dried at 60 degrees Celsius at least three days before being weighed on a four-point balance with glass enclosure. The mass of each sample can be found in the "PF_ShootHarvest_Data" file. CHN ANALYSIS: Grinding: All leaf samples were dried in an oven at 60°C before grinding. Samples were small enough to grind the entire sample without subsampling. Leaves were ground using the Retsch MM 200 for 3 minutes or until a talcum powder consistency was achieved. Weighing: After grinding, samples were stored in glass scintillation vials and dried again at 60°C for at least 36 hours. Once samples were removed, vials were tightly re-capped. When not in use, vials were stored in dessicators. 3.5-4.5 mg of each sample was weighed into a 10x12 mm tin capsule. A standard calibration curve was created using increasing amounts of aspartic acid (from about 0.2 mg to 5.0 mg). A chemical standard, acetanilide, and an organic sample, apple leaf, were run after the standard curve. Every ten samples, an aspartic acid check standard and a duplicate of an already-packed sample were run. CN analysis: CN analysis was run between 10/4/2012 and 11/15/2012 by Rachel Rubin using the ThermoScientific 2000 at the Ecosystems Center, MBL, Woods Hole, MA. Duplicate sample values were averaged (mass, %N and %C) before inclusion into final results. The CHN data is available in the file "PF_CHN_Data". CURVE MODELS: Once corrected for the actual leaf area, the A/Ci curve for each shoot was modelled using the equations and Excel worksheet published by Sharkey et al. (2007). The equations used in the model are listed below for reference, though the complete model description and worksheet can be found online and downloaded at: http://www.blackwellpublishing.com/plantsci/pcecalculation/ . The ITEX manual updated in 2011 also contains a description of how to process the LI-6400 data and use this model for A/Ci curve data. The equations used in the A/Ci curve model are listed below, as described in Sharkey et al (2007): Rubisco-limited photosynthesis: Where: A = rate of photosynthesis (umol CO2 m-2 s-1) Vcmax = maximum velocity of Rubisco for carboxylation Cc = partial pressure of CO2 at Rubisco Kc = Michaelis constant of Rubisco for CO2 Omicron (?) = partial pressure of O2 at Rubisco Ko = inhibition constant (usually taken to be the Michaelis constant) of Rubisco for O2 Rd = rate of respiration (umol CO2 m-2 s-1) ?* = CO2 concentration at which oxygenation proceeds at twice the rate of carboxylation, causing photosynthesis rate = respiration rate (photorespiration compensation point) Rubisco regeneration-limited photosynthesis: Where: A = rate of photosynthesis (umol CO2 m-2 s-1) J = rate of electron transport (assumes 4 electrons / carboxylation and oxygenation) Cc = partial pressure of CO2 at Rubisco Rd = rate of respiration (umol CO2 m-2 s-1) ?* = CO2 concentration at which oxygenation proceeds at twice the rate of carboxylation, causing photosynthesis rate = respiration rate (photorespiration compensation point) Triose- phosphate unit (TPU)-limited photosynthes: Where: A = rate of photosynthesis (umol CO2 m-2 s-1) TPU = rate of use of triose phosphates (can also be any export of C from the Calvin cycle) Rd = rate of respiration (umol CO2 m-2 s-1) Mesophyll Conductance (gm*) Equations (1 ) - (3) were developed for chloroplast metabolism, and thus a relationship is needed between the chloroplast and leaf-level gas exchange. This is done through the mesophyll conductance constant calculated with equation (4): Where: Cc = partial pressure of CO2 at Rubisco (Pa) Ci = intercellular CO2 concentration (umol CO2) A = rate of photosynthesis (umol CO2 m-2 s-1) gm = mesophyll conductance rate (umol CO2 m-2 s-1 Pa-1 ) POINT FRAME PIN-DROP METHODS: We preferentially selected tall shrub canopies dominated either by Betula nana or Salix pulchra, that is canopies that were greater than 75 cm height. Care was taken to select fairly uniform canopies, that is avoiding the edge of a shrub stand or areas where the canopy had a large gaps, suggesting the area may have been disturbed. We used point frames constructed from a 1.1 m x 1.1 m aluminum square with holes in each corner to accomodate steel rod posts used as the legs of the point frame. In this way, the frame could rest upon the four leg posts that had been hammered into the ground and remain adjustable in each corner. The frame had a level on each side, and great care was taken to ensure that the frame was (a) unable to be pushed deeper into the ground and, (b) level on all four sides prior to taking measurements. These factors were important to the measurement to have accurate data regarding the distance from the frame and the overall height of each point sampled in the canopy. The aluminum frame had numbered, regularly spaced holes on two opposite sides in order to accomodate a metal bar that could be placed across the frame and locked into place. [These holes on the frame are the row numbers.] The bar that was placed across the frame similarly had numbered, evenly spaced holes in order to accomodate a pin--a long (100-200cm) metal rod with a diameter of ~3.175 mm. [The holes on this bar are the pin hole numbers.] Measurements were only ever taken from odd row numbers, and alternated even/odd pin hole numbers with each row; in this way, for every plot 25 evenly spaced locations were sampled covering an area of one square meter. The length of the pin was marked every half-centimeter so that the distance could be read easily. Measurements were made by lowering the pin through a pin hole and, once encountering a leaf or stem, recording the following: row#, pin hole#, hit#, and the species hit. If the object hit was not a leaf, the plant tissue was noted; the diameter of each stem hit was estimated in millimeters, and the length of every graminoid blade hit was recorded from the point at which it was hit to the tip. As the primary species of interest for this project were for a select number of species (B. nana, S. pulchra, S. glauca, S. reticulata, V. uliginosum, V. vitis, L. palustre), species that were not the target of interest were classified as functional groups--e.g. graminoid spp., forb, moss. The last pin-hit recorded for each pin hole was always at the "soil" which was considered to be the transition between the green and brown plant material, often in a mossy layer. References: Sharkey, T.D., Bernacchi, C. J., Farquar, G.D. and Singaas, E.L., 2007. Fitting photosynthetic carbon dioxide response curves for C3 leaves. Plant, Cell and Environment, 30: 1035–1040. doi: 10.1111/j.1365-3040.2007.01710.x http://www.blackwellpublishing.com/plantsci/pcecalculation/ ITEX Manual Updated in 2011. pers-1 http://www.blackwellpublishing.com/plantsci/pcecalculation/ Sharkey, T.D., Bernacchi, C. J., Farquar, G.D. and Singaas, E.L., 2007. Fitting photosynthetic carbon dioxide response curves for C3 leaves. Plant, Cell and Environment, 30: 1035–1040. doi: 10.1111/j.1365-3040.2007.01710.x ITEX Manual, updated 2011 Gus Shaver

The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole MA 02543 USA

(508) 289 7496 gshaver@mbl.edu Lead PI Jim Laundre

The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole MA 02543 USA

(508) 289 7496 arc_imr@mbl.edu Information Manager The goal of Arctic LTER project is to predict the future ecological characteristics of the site based upon our knowledge of the controls of ecosystem structure and function as exerted by physical setting and geologic factors, climatic factors, biotic factors, and the changes in fluxes of water and materials from land to water. To achieve this goal the Arctic LTER uses several approaches: Long-term monitoring and surveys of natural variation of ecosystem characteristics in space and time. Includes: climate, plant communities and productivity, thaw depth, stream flow, chemistry of streams and lakes, temperatures of streams and lakes, lake chlorophyll lake productivity, zooplankton abundance. Experimental manipulation of ecosystems for years and decades. Includes: tundra warming, shading, and fertilizing, grazer exclusions, fertilization of lakes and streams, addition and subtraction of predators. Synthesis of results and predictive modeling at ecosystem and watershed scales. Includes: stream N cycling, lake physics, bioenergetics of fish populations, water movement and transfer of DOC and nutrients from land to water, soil respiration, cycling and storage of C in tundra under different scenarios of future climates. 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. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The Arctic LTER research site (68°N and 149°W) is in the foothills region of the North Slope of Alaska and includes the entire Toolik Lake watershed and the adjacent watershed of the upper Kuparuk River, down to the confluence of these two watersheds. This area is typical of the northern foothills of the Brooks Range, with continuous permafrost, no trees, a complete snow cover for 7 to 9 months, winter ice cover on lakes, streams, and ocean, and cessation of river flow during the winter. Tussock tundra vegetation of sedges and grasses mixed with dwarf birch and low willows form the dominant vegetation type with areas of drier heath tundra on ridge tops and other well-drained sites as well as areas of river-bottom willow communities. -149.75 -149.0433 68.8 68.5 610 1360 meter 2012_GS_ITEX_PF_ShootACiData.csv A/Ci curve parameters measured from shoots harvested at three levels in the canopy from 19 1m x 1m plots dominated by S. pulchra and B. nana shrubs near LTER Shrub plots at Toolik Field Station, AK the summer of 2012. 2012_GS_ITEX_PF_ShootACiData.csv 1 \r\n column , " http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.10144&urlTail=terrest/tracegas/data/2012_GS_ITEX_PF_ShootACiData.csv YEAR YEAR year of measurement yyyy DATE DATE date of measurement dd-mon-yy SITE SITE Toolik Toolik GROUP GROUP Measurement location in relation to Toolik Lake LTER Shrub plots; In vicinity of Block1 = Upland, IVO Block 2 = Outlet Measurement location in relation to Toolik Lake LTER Shrub plots; In vicinity of Block1 = Upland, IVO Block 2 = Outlet PLOT PLOT Individual plot identifier Individual plot identifier TREATMENT TREATMENT control or fertilized annually (with N and P) control or fertilized annually (with N and P) PLOT SIZE PLOT SIZE 1m x 1m point frame size 1m x 1m point frame size DOMINANT VEGETATION DOMINANT VEGETATION Dominant canopy vegetation Dominant canopy vegetation SPP SPP Shoot species sampled Shoot species sampled SHOOT ID SHOOT ID Identification for each shoot sampled (NOT unique); consists of canopy position (up/mid/low), species abbreviation, and a number Identification for each shoot sampled (NOT unique); consists of canopy position (up/mid/low), species abbreviation, and a number CANOPY POSN CANOPY POSN Relative position of shoot in the canopy Relative position of shoot in the canopy AMBIENT CO2 BEFORE MEASUREMENTS AMBIENT CO2 BEFORE MEASUREMENTS Carbon dioxide concentration in the room at the beginning of measurements (umol CO2 per mole air) micromolePerMole real not recorded Missing or Not Measured AMBIENT CO2 AFTER MEASUREMENTS AMBIENT CO2 AFTER MEASUREMENTS Carbon dioxide concentration in the room after taking measurements (umol CO2 per mole air) micromolePerMole real not recorded Missing or Not Measured AVG LEAF TEMP AVG LEAF TEMP Average leaf temperature during measurement (deg C) celsius real #N/A Missing or Not Measured AVG PRESSURE AVG PRESSURE Average pressure during measurement atmosphere real #N/A Missing or Not Measured SUM(LEAF, PETIOLE, STIPULE) AREA SUM(LEAF, PETIOLE, STIPULE) AREA Area of the shoot leaves, petioles, and stipules used to correct light curve data (square cm leaf+petiole+stipule) centimeterSquared real #N/A Missing or Not Measured LMA LMA Leaf mass per unit area (g leaf per square cm leaf) gramPerMeterSquared real #N/A Missing or Not Measured Resp_Real Resp_Real Rate of CO2 change measured in the dark of light curve and used to estimate respiration rate (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Vcmax @LeafT Vcmax @LeafT Modeled CO2 assimilation at maximum carboxylation efficiency of the Rubisco enzyme at leaf temperature (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Jmax @LeafT Jmax @LeafT Modeled CO2 assimilation at maximum electron transportation efficiency at leaf temperature (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured TPU @LeafT TPU @LeafT Modeled CO2 assimilation at maximum triose-phosphate utilization at leaf temperature (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Rd @LeafT Rd @LeafT Modeled respiration rate at leaf temperature (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured gm* @LeafT gm* @LeafT Modeled mesophyll conductance at leaf temperature (umol CO2 per meter squared leaf per second per Pascal) micromolePerMeterSquaredPerSecondPerPascal real #N/A Missing or Not Measured Vcmax @25°C Vcmax @25°C Modeled CO2 assimilation at maximum carboxylation efficiency of the Rubisco enzyme at 25°C (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Jmax @25°C Jmax @25°C Modeled CO2 assimilation at maximum electron transportation efficiency at 25°C (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured TPU @25°C TPU @25°C Modeled CO2 assimilation at maximum triose-phosphate utilization at 25°C (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Rd @25°C Rd @25°C Modeled respiration rate at 25°C (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured gm* @25°C gm* @25°C Modeled mesophyll conductance at 25°C (umol CO2 per meter squared leaf per second per Pascal) micromolePerMeterSquaredPerSecondPerPascal real #N/A Missing or Not Measured Ci 50 Ci 50 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 50 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 100 Ci 100 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 100 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 200 Ci 200 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 200 umol CO2 micromolePerMole real #N/A Missing or Not Measured Ci 300 Ci 300 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 300 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 400 (1) Ci 400 (1) Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 400 umol CO2- first observation (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 400 (6) Ci 400 (6) Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 400 umol CO2- sixth observation (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 400 (13) Ci 400 (13) Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 400 umol CO2- thirteenth observation (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 500 Ci 500 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 500 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 700 Ci 700 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 700 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 900 Ci 900 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 900 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 1300 Ci 1300 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 1300 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 1500 Ci 1500 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 1500 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Ci 1700 Ci 1700 Modeled CO2 concentration of the intercellular airspaces of the leaf when the target [CO2] was 1700 umol CO2 (umol CO2 per mole air) micromolePerMole real #N/A Missing or Not Measured Photo @ CO2R 50 Photo @ CO2R 50 Photosynthetic rate when the target [CO2] was 50 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 100 Photo @ CO2R 100 Photosynthetic rate when the target [CO2] was 100 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 200 Photo @ CO2R 200 Photosynthetic rate when the target [CO2] was 200 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 300 Photo @ CO2R 300 Photosynthetic rate when the target [CO2] was 300 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 400 (1) Photo @ CO2R 400 (1) Photosynthetic rate when the target [CO2] was 400 umol CO2 - first observation (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 400 (6) Photo @ CO2R 400 (6) Photosynthetic rate when the target [CO2] was 400 umol CO2 - sixth observation (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 400 (13) Photo @ CO2R 400 (13) Photosynthetic rate when the target [CO2] was 400 umol CO2 - thirteenth observation (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 500 Photo @ CO2R 500 Photosynthetic rate when the target [CO2] was 500 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 700 Photo @ CO2R 700 Photosynthetic rate when the target [CO2] was 700 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 900 Photo @ CO2R 900 Photosynthetic rate when the target [CO2] was 900 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 1300 Photo @ CO2R 1300 Photosynthetic rate when the target [CO2] was 1300 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 1500 Photo @ CO2R 1500 Photosynthetic rate when the target [CO2] was 1500 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured Photo @ CO2R 1700 Photo @ CO2R 1700 Photosynthetic rate when the target [CO2] was 1700 umol CO2 (umol CO2 per meter squared leaf per second) micromolePerMeterSquaredPerSecond real #N/A Missing or Not Measured COMMENTS COMMENTS Notes on data quality and measurements Notes on data quality and measurements 115 2012_GS_ITEX_PF_ShootACiData.xlsx An excel file that has worksheets with the metadata and data. 2012_GS_ITEX_PF_ShootACiData.xlsx Microsoft Excel http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.10144&urlTail=terrest/tracegas/xlsfiles/2012_GS_ITEX_PF_ShootACiData.xlsx Microsoft Excel file concentration of substance square centimeters grams per square meter micro Einsteins (1E-06 moles of photons) per square meter per second (radiant flux density)