Above ground plant and belowground stem biomass was measured in moist acidic and non-acidic tussock tundra experimental sites. Treatments sampled were control plots and plots amended with nitrogen and phosphorus.
Ecosystem CO2 flux light response curves were measured on 1m x 1m plots ( some 0.3m x 0.3m plots in 2006 and some 0.7m x0.7m plots in 2009) across the arctic. This file contains the best fit parameters that describe these light response curves, together with corresponding NDVI data for each curve.
Maximum canopy height measurements for deciduous shrub canopies sampled for both 1m x 1mc hamber flux polots (n=14) and point frame plots (n=19) in the summer of 2012 near LTER shrub plots at Toolik Lake, AK. The canopies were dominated either by Salix pulchra or Betula nana species, and plot locations were preferentially selected for tall canopies (height > 75 cm). The methods for the chamber flux and point frames are outlined here briefly, though the data from these measurements are contained in separate files.
“Flux data” contains the CO2 and water flux data along with the corresponding diffuse light fraction at the time of measurement from the ITEX shrub canopy project taken at Toolik Lake, Alaska in 2012. Each record is a single LiCor flux measurement made with LiCor 6400 photosynthesis system, with associated average pressure, temperature, PAR, water vapor, and other data such as NDVI and LAI measurements taken with a DeltaT SunScan wand under both direct and diffuse light conditions.
Summary of three methods used to estimate the Leaf Area Index (LAI) of 19 1m x 1m plots sampled with a point frame near the LTER Shrub plots at the Toolik Field Station in AK the summer of 2012. The methods used were: (1) exponential relationship between LAI and NDVI as measured above the canopy with a Unispec spetroradiometer; (2) Delta-T SunScan canopy analyzer held at 5 cm above the ground under both direct and diffuse light conditions; (3) pin-drop point frame tequnique. Where values have been averaged (such as for the NDVI and SunScan measurements), the standard deviation is given.
Leaf area index (LAI) measurements were taken with the Delta-T SunScan wand every 15 cm from the ground to above the canopy under both direct and diffuse light. conditions The data includes all outputs from the SunScan wand: time of measurement, transmitted light, spread of PAR sensors, beam fraction, and zenith angle.
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.
This dataset contains light response curves and modeled light curve parameters from shoots clipped from low, mid, and the top parts of tall, shrub canopies dominated either by Salix pulchra or Betula nana. Six shoots were harvested from each 1m x 1m plot, two from each level in the canopy in plots located near the LTER shrub plots at Toolik Field Station, AK 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.
This file contains limited daily summaries of PAR, relative humidity, and temperature data monitored above, within, and below Betula nana and Salix pulchra shrub canopies at two locations near Toolik Lake, Alaska during the summer of 2012. The location of the PAR sensor and dataloggers were co-located with the LTER shrub plots (block 1 and 2), also used for the chamber flux and point frame measurements taken this same year.
14 1m x 1m shrub plots were sampled the summer of 2012 under direct and diffuse light conditions. Light response curves were measured under each light condition for each plot using a Li-Cor 6400 to measure net ecosystem exchange (NEP); these measurements were modelled using a saturatingMichaelis-Menton formula.
This file contains irradiance (PAR) and diffuse light data logged from a beam fraction (BF3) sensor near Toolik Lake, Alaska during the summer of 2012. The data comes from a compilation of automated datalogger readings as well as measurements taken during the field season in conjunction with the Delta-T SunScan wand to measure PAR in tall shrub canopies dominated by Betula nana or Salix pulchra species. The sensor was leveled and mounted to a 2m tripod in each location, and programmed to record instantaneous readings in 30 second to 5 minute intervals.
"2012_GS_PFandCH_GPS" contains GPS locations of all datalogger, 1m x 1m chamber flux and point frame plots sampled IVO Toolik Field Station in Alaska during the summer of 2012. The sorting variables (YEAR, DATE, SITE, GROUP, PLOT, TREAT, PLOT SIZE) are identical to those in other files with data collected that season. The main purpose of this file is for reference and as an aid in interpretation of data analyses and among-site comparisons.
Leaf and plant tissue area and mass from shoots harvested from 19 1m x 1m point frame plots near Toolik Field Station, AK during the summer of 2012. Six shoots were harvested from each plot, two from each canopy layer: upper, middle, and low. Each shoot came from a different plant, and the species selected was based on the species dominant in that canopy layer. The leaf area and mass were used to correct A/Ci and light response curves taken on each shoot [data published separately].
This file contains PAR , relative humidity, and temperature data logged every five minutes from within, below, and above Betula nana and Salix pulchra shrub canopies at two locations near Toolik Lake, Alaska during the summer of 2012. The location of the PAR sensor and dataloggers were co-located with the LTER shrub plots (block 1 and 2), also used for the chamber flux and point frame measurements taken this same year.
Above ground plant and below ground stem biomass were measured in 2011 from three sites at and around the Anaktuvuk River Burn: severely burned, moderately burned and unburned. These samples were analyzed for carbon and nitrogen concentrations.
Decadal file describing the chlorophyll a and primary production in various lakes near Toolik Research Station (68 38'N, 149 36'W) during summers from 2010 to 2014. Sample site descriptors include an assigned number (sortchem), site, date of analysis (incubation), time, depth and rates of primary production. The amount of chlorophyll a and pheophytin were also measured.
Above ground plant biomass and leaf area were measured in a tussock tundra experimental site. The plots were set up in 1981 and have been harvested in previous years (See Shaver and Chapin Ecological Monographs, 61, 1991 pp.1-31).
Leaf areas were measured on quadrats harvested in Arctic LTER tussock tundra experimental small mammal exclosures. Treatments included Control, Nitrogen plus Phosphorus with both fenced and unfenced plots. In addition a moist non-acidic tussock tundra site was harvested. Biomass was also measured for each quadrat but is in a separate file.
Above ground plant biomass was measured in a tussock tundra experimental site. The plots were set up in 1981 and have been harvested in previous years (See Shaver and Chapin Ecological Monographs, 61(1), 1991 pp.1-31.) This file is the July 26-27, 1984 harvest of the controls and nitrogen + phosphorus treatments.
Percent carbon and percent nitrogen were measured from above ground plant and belowground stem biomass samples from experimental plots in moist acidic and moist non-acidic tundra. Biomass data are in 2001lgshttbm.dat.
Aboveground plant and belowground stem biomass were measured in moist acidic and moist non-acidic tussock tundra experimental plots. Treatments at the acidic site include control and nitrogen (N) plus phosphorus (P) amendments; treatments at the non-acidic site include N, P, N+P, greenhouse warming, and greenhouse+N+P.
Note: Version 8 corrected an error where Carex vaginata was listed twice under treatment of "Nitrogen Phosphorus". The tissues with 8 quadrats were "Greenhouse" treatment.
The data set describes stable carbon and nitrogen isotopes and carbon and nitrogen concentrations from an August 2012 pluck of a fertilization experiment begun in 2006. Fertilization was with nitrogen (N) and phosphorus (P). Fertilization levels included control, F2, F5, and F10, with F2 corresponding to yearly additions of 2 g/m2 N and 1 g/m2 P, F5 corresponding to yearly additions of 5 g/m2 N and 2.5 g/m2 P, and F10 corresponding to yearly additions of 10 g/m2 N and 5 g/m2 P. After harvest, plants were separated by species and then by tissue.
In contribution to the Arctic Observing Network (AON), the researchers have established two observatories of landscape-level carbon, water and energy balances at Imnaviat Creek, Alaska and at Pleistocene Park near Cherskii, Russia. These will form part of a network of obervatories with Abisko (Sweden), Zackenburg (Greenland) and a location in the Canadian High Arctic which will provide further data points as part of the International Polar Year. This particular part of the project focuses on simultaneous measurements of carbon, water and energy fluxes of the terrestrial landscape at hour
Decadal file describing the chlorophyll a and primary production in various lakes near Toolik Research Station (68 38'N, 149 36'W) during summers from 2000 to 2009. Sample site descriptors include an assigned number (sortchem), site, date of analysis (incubation), time, depth and rates of primary production. The amount of chlorophyll a and pheophytin were also measured.