Data file containing biogeochemical data of water samples collected in Imnavait Creek, North Slope of Alaska. Sample site descriptors include a unique assigned number (sortchem), site, date, time, depth, distance (downstream), and elevation. Values of variables measured in the field include temperature, conductivity, pH. Chemical analysis for samples include alkalinity, dissolved organic carbon, inorganic and total dissolved nutrients particulate carbon, nitrogen, and phosphorus, cations and anions.
Data Set Results
This file contains the soil profile data for burned and unburned moist acidic tundra sites used to estimate C and N loss from the Anaktuvuk River Fire (2007). These sites were sampled in summer of 2008. Unburned sites were used to develop a method for estimating soil organic layer depth and plant biomass, and for determining the characteristics of unburned soil organic layers. In burned sites, we characterized residual organic soils and used biometric measurements of tussocks to reconstruct pre-fire soil organic layer depth.
In 1980-1982, six transplant gardens were established along a latitudinal gradient in interior Alaska from Eagle Creek, AK in the south to Prudhoe Bay, AK in the north. Three sites, Toolik Lake (TL), Sagwon (SAG), and Prudhoe Bay (PB) are north of the continental divide and the remaining three, Eagle Creek (EC), No Name Creek (NN), and Coldfoot (CF), are south of the continental divide. Each garden consisted of 10 individual Eriophorum vaginatum tussocks transplanted back to their home-site, as well as 10 individuals from each of the other transplant sites.
Data file describing the biogeochemistry of samples collected at various sites near Toolik Lake on the North Slope of Alaska. Sample site descriptors include a unique assigned number (sortchem), site, date, time, depth, and category (level of thermokarst disturbance). Physical measures collected in the field include temperature, electrical conductivity, and pH.
1997 measurements of Leaf area, foliar C and N for 14 sites along a transect down the Kuparuk River basin, North Slope, Alaska.
Above ground plant and below ground stem biomass, percent nitrogen, and percent carbon were measured in the Arctic LTER moist acidic tundra experimental plots. Treatments included control, and nitrogen and phosphorus amended plots for 10 years, and exclosure plots with and without added nitrogen and phosphorus.
Biomass of belowground community groups (bacteria, fungi, protozoa, nematodes, rotifers, tardigrades) determined for organic and mineral soils in moist acidic tundra. Soil carbon and nitrogen content, bulk density, and depth are included.
Above ground plant and below ground stem biomass, percent nitrogen, and percent carbon were measured in the Arctic LTER dry heath tundra experimental plots. Treatments included control, and nitrogen and phosphorus amended plots for 10 years, and exclosure plots with and without added nitrogen and phosphorus.
Percent moisture, bulk density, percent loss on ignition and percent organic carbon were measured for peat collected from soils in the Imnavait Creek watershed.
In situ soil respiration measured in the Arctic LTER treatment plots in moist acidic tussock and moist non-acidic tussock tundra
Soil aggregate size distribution, aggregate carbon and nitrogen, and light fraction carbon were determined for mineral soils in moist acidic tundra. Soil was sampled in control, and N+P plots of the Arctic LTER Moist Acidic Tundra plots established in 1989 and 2006.
This file is from the Long-term Carbon and Nitrogen, and Phosphorus Dynamics of Leaf and Fine Root Litter project (LIDET-Long-term Intersite Decomposition Experiment Team). This file contains only the Arctic LTER data. In particular the mass looses over the ten year study. Three types of fine roots (graminoid, hardwood, and conifer), six types of leaf litter (which ranged in lignin/nitrogen ratio from 5 to 75), and wooden dowels were used for litter incubations over a ten year period.
In arctic tundra, near Toolik Lake, Alaska, we quantified net N-mineralization rates under ambient and manipulated snow treatments at three different plant communities that varied in abundance and height of deciduous shrubs.
These data are from two remote field campaigns in the Noatak National Preserve. Various thermokarst features and their receiving streams were sampled and characterized. A suite of water chemistry (nutrients, major anions and cations, total suspended sediment) and benthic variables (particulate carbon, nitrogen and phosphorus, and chlorophyll-a) were measured at 6 major sites (2 in 2010 and 4 in 2011). There were additional sites sampled for water chemistry above and below thermokarst features in 2011.
Water samples were taken at 5 locations at both I-Minus2 and Toolik River thermokarst sites (10 sampling locations total). A combination of ISCO and manual grab samples were taken depending on the sampling location and year.
Surface organic and mineral soil layers were sampled in retrogressive thaw slump disturbance scars and nearby undisturbed tundra to estmate the influence of this thermo-erosional--thermokarst--disturbance type on soil carbon (C) and nitrogen (N) pools. Within six independent sites, we identified multiple thaw slump scars and determined time after disturbance for each scar by (1) aging the population of tall deciduous shrubs rooted in the mineral soil and (2) by dating the basal layer of the re-accumulating soil organic matter.
This file contains data collected from thermokarst impacted soils, lakes, and streams near Toolik Lake Alaska. Data are also presented for experimental manipulations of water (e.g., time course experiments). Sample descriptors include a unique sortchem #, site, date, time, depth, distance, elevation, treatment, date-time, category, and water type (e.g., lake, surface, soil). Physical/chemical measures collected in the field include temperature, conductivity, and pH.
Hourly air temperature, humidity, wind speed, soil temperature and soil water data from the control area of the ITEX tussock tundra snowfence study site
Soil temperature from three locations on the eastern side of the Toolik River where by snow fences were established as part of IPY. This is a study of how soil temperatures at 10 cm and soil moisture change across the summer at our IPY snow fence site .
The Changing Seasonality of Arctic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of through flow, lateral inputs, and hyporheic regeneration on the seasonal fluxes C, N, and P in an arctic river network, and to determine how these influences might shift under seasonal conditions that are likely to be substantially different in the future. Point transects were done throughout the sampling season to determine different substrate and cover types on the stream bottom.
The Changing Seasonality of Arctic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of through flow, lateral inputs, and hyporheic regeneration on the seasonal fluxes C, N, and P in an arctic river network, and to determine how these influences might shift under seasonal conditions that are likely to be substantially different in the future. During the project, well and mini-piezometer samples were collected from various depths near stream channels and analyzed for a variety of nutrients.
The Changing Seasonality of Arctic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of through flow, lateral inputs, and hyporheic regeneration on the seasonal fluxes C, N, and P in an arctic river network, and to determine how these influences might shift under seasonal conditions that are likely to be substantially different in the future. During the project, background samples were collected from four stream channels and analyzed for a variety of nutrients.
The Changing Seasonality of Arctic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of through flow, lateral inputs, and hyporheic regeneration on the seasonal fluxes C, N, and P in an arctic river network, and to determine how these influences might shift under seasonal conditions that are likely to be substantially different in the future. Whole Stream Metabolism was calculated using dissolved oxygen, discharge, stage, and temperature measured by sounds deployed in the field.
The (ARCSSTK) did extensive research during 2009-2011 field seasons in Arctic Alaska. Specifically, the ARCSSTK goal Streams goal was to quantify the relative influences of thermokarst inputs on the biogeochemical structure and function of receiving streams. Whole Stream Metabolism was calculated using dissolved oxygen, discharge, stage, and temperature measured by sondes deployed in the field.
Plant available NH4, NO3, and PO4 was determined at three site (LTER Toolik acidic tundra, LTER Toolik nonacidic tundra, and Sagwon acidic tundra) and three community combinations (tussock, watertrack, and snowbed), three times during the season. pH was also determined in July and strong acid phosphorous in August.
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.
Percent carbon, percent nitrogen, del13C and del15N 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 2000lgshttbm.dat.
A spectrophotometer was used to scan the canopy vegetation at four sites along Imnavait Creek in the Kuparuk Watershed near Toolik Lake LTER, Alaska. The resulting reflectance spectra were used to calculate average vegetation indices for each site and collection day.
Bulk precipitation was collected during summer months (June, July and August) on a per rain event basis at the University of Alaska Fairbanks Toolik Field Station, North Slope of Alaska (68 degrees 37' 42"N, 149 degrees 35' 46"W). Analysis of pH, NH4-N and phosphorus were performed at the field station. NO3-N were frozen and analyzed in Woods Hole, MA
Extractable NH4-N and NO3-N (2 N KCl), PO4-P
(0.025 N HCl) and pH (0.01 M CaCl2) were measured on soils from a
transect along the Dalton road. Sites are Gus Shaver flowering sites and
Arctic LTER sites.
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.
Quadrats (20cm x 20cm squares) along a line (block) were collected for plant biomass in mesic tussock tundra. In the lab each quadrat was separated into individual species, new and old aboveground and belowground biomass. Two harvests were completed, June and a late July. These are control plots from an experiment setup for a 15N experiment.
Five or six quadrats (20cm x 20cm squares) along a line (block) were collected for plant biomass in mesic tussock tundra. In the lab each quadrat was separated into individual species, new and old aboveground and belowground biomass.
Vegetation indices calculated from reflectance spectra collected at Arctic LTER experimental plots at Toolik Lake, Alaska during the 2007-2019 growing seasons.
Biomass in wet sedge tundra near the Atigun River crossing of the Dalton Highway, North Slope AK. .There were three harvests; Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61, 1991 pp.1-31.
Biomass, nitrogen and carbon of plants in the Arctic LTER experimental wet sedge tundra experimental sites, 2001, Toolik Lake, Alaska.. Treatments at each site included factorial NxP, greenhouse and shade house and were begun in 1985 (Sag site) or in 1988 (Toolik sites).
Biomass in tussock tundra near Toolik Lake North Slope AK (68 degrees 38N, 149derees 34W). There were three harvests;Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61(1), 1991 pp.1-31.
Biomass was harvested from six vegetation types along a toposequence on a floodplain terrace of the Sagavanirktok River in the northern foothills of the Brooks Range , Alaska (68degrees 46' N, 148 degrees 51' W 50m). The vegetation sites are; upland tussock tundra, "hilltop heath", a "hillslope shrub-lupine", a "footslope Equisetum", a wet sedge tundra, and a "riverside willow".
Quadrats (20cm x 20cm squares) along a line (block) were collected for plant biomass in mesic acidic tussock tundra. Each quadrat was separated into individual species, new and old aboveground and belowground biomass. The harvest occurred in early July to coincide with a 15N plant and soil harvest.
Quadrats were harvested for aboveground biomass from eight plots within a tussock, watertrack, and snowbed community at 3 sites - acidic tundra near Toolik (site of acidic LTER plots), nonacidic tundra near Toolik Lake(site of non-acidic LTER plots), and acidic tundra near Sagwon. All vascular species were sorted, divided into new and old growth, dried, and weighed. Lichens were separated by genus in all quadrats. In half of the quadrats (n=4), mosses were separated by species. Moss and lichen data are presented by species elsewhere (see 97lgmosslichen.txt).
Leaf area for select species was measured in arctic tundra experimental sites from late June into early August. Measurements were made in acidic and non acidic tussock tundra and in shrub tundra in control and fertilized plots.
Biomass in shrub tundra near Toolik Lake North Slope AK (68 degrees 38N, 149derees 34W). There were three harvests; Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61(1), 1991 pp.1-31.
Plant available NH4, NO3, and PO4 was determined at sites near ARC LTER Toolik acidic tundra and at a toposequence along the floodplain of the Sagavanirktuk River using 2 N KCL and weak HCL extracts. This file complies data collected at different times from 1987 through 2001 and includes initial extracts taken for buried bag method of net nitrogen mineralization.
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 contains the biomass numbers for each harvested quadrat.
A spectrophotometer was used to scan the canopy vegetation of ITEX harvest plots. The resulting reflectance spectra were used to calculate several vegetation indices of interest (NDVI, EVI, EVI2, PRI, WBI, Chlorophyll Index). Average values of these vegetation indices for each ITEX harvest plot are presented here. These plots also had biomass harvests performed and were analyzed for leaf area and nitrogen content (see 2003-2009gsharvest.csv, 2003-2009gsharvestLAI-N.csv).
Plant biomass in arctic heath experimental plots. Plots set up in 1989 with nitrogen, phosphorus, nitrogen plus phosphorus and a shade treatment were harvested for above ground biomass. Root mass was also measured on a smaller subsample.
Above ground plant and below ground stem biomass was measured 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. Leaf areas were also measured for each quadrat but are in a separate file.
A harvest was conducted to determine productivity of rare species not found in at least 4 quadrats per site in a separate small quadrat aboveground biomass harvest (see 97lg3sbm.txt). Harvests occurred in a tussock, watertrack, and snowbed community at 3 sites - acidic tundra near Toolik (site of acidic LTER plots), nonacidic tundra near Toolik Lake(site of non-acidic LTER plots), and acidic tundra near Sagwon. Moss and lichen data are presented by species elsewhere (see 97lgmosslichen).
Biomass in tussock tundra experimental plots near Toolik Lake, North Slope, AK (68 degrees 38N, 149derees 34W). There were five harvests in 1983. This file is the May 21-22, 1983 harvest.
Biomass in heath tundra near Toolik Lake North Slope AK (68 degrees 38N, 149derees 34W). .There were three harvests;Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61(1), 1991 pp.1-31.