Soil samples were collected from control, and N+P plots from within a set of treatments in Arctic LTER Moist Acidic Tundra plots established in 1989 and in 2006 . At the time of sampling the soil was separated into organic horizon, organic/mineral interface, and the upper 5cm of the mineral soil. In the lab the potential activities of seven hydrolytic enzymes was determined using fluorometric techniques (Saiya-Cork et al. 2002) modified following Steinweg et al(.2012).
Data Set Results
Displaying 51 - 100 of 412
Weekly growth of plant species of three growth forms were measured in the ninth year of a long-term experiment at Toolik Field Station. The experimental treatments excluded small and large mammalian herbivores and increased soil nutrients in two arctic Alaskan tundra communities: moist acidic tussock and dry heath. This data set reports the deciduous dwarf shrub species. Please see 2004lggrgram for the tussock-forming and rhizomatous graminoid species growth data.
In arctic tundra near Toolik Lake, Alaska, we incubated a common substrate in a snow addition experiment to test whether snow accumulation around arctic deciduous shrubs altered the environment enough to increase litter decomposition rates. We compared the influence of litter quality on the rate of litter and N loss by decomposing litter from four different plant functional types in a common site. We used aboveground net primary production values and estimated k values from our decomposition experiments to calculate community-weighted mass loss for each site.
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.
In 2010, Relative percent cover of plant species was measured in the Arctic LTER's experimental and control plots across several habitats: moist acidic, dry heath, and moist non-acidic tundra; in new variable (low) nutrient addition experimental plots established in 2006; and for Sagavanirktok River toposequence plots in tussock and heath tundra.
Relative percent cover was measured for plant species on Arctic LTER experimental plots at Toolik field station in moist acidic tussock and dry heath tundra.
In 2008, Relative percent cover of plant species was measured in the Arctic LTER's experimental and control plots across several habitats: moist acidic, dry heath, and moist non-acidic tundra; in new variable (low) nutrient addition experimental plots established in 2006; and for Sagavanirktok River toposequence plots in tussock and heath tundra.
Foliar nutrients (N, P, K, Ca, Mg, Al) for dominant species on moist acidic and non-acidic tundra, Arctic LTER, Toolik Field Station , Alaska, 1999.
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.
Weekly growth of plant species of three growth forms were measured in the ninth year of a long-term experiment at Toolik Field Station. The experimental treatments excluded small and large mammalian herbivores and increased soil nutrients in two arctic Alaskan tundra communities: moist acidic tussock and dry heath. This data set reports the four graminoid (both tussock and rhizomatous forms) species. Please see 2004lggrbnan for Betula nana (dwarf shrub) growth data.
Biomass of belowground community groups (bacteria, fungi, protozoa, nematodes, rotifers, tardigrades) determined for organic soils in moist acidic tundra and dry heath tundra.
Foliar and litter nutrients and retranslocation efficiencies (N, P, K, Ca, Mg) for dominant species on moist acidic and non-acidic tundra, Arctic LTER, Toolik Field Station , Alaska, 1999.
Relative percent cover was measured for plant species on Arctic LTER experimental plots at Toolik field station in moist acidic and moist non acidic tussock tundra, and dry heath tundra, and on Sagavanirktok River toposequence plots in tussock and heath tundra.
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.
File contains temperature and discharge data for Lake NE 14 Outlet during the 2011 summer field season.
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.
Data were collected to investigate if formation of gully thermokarst (TK) results in lowering of the water table and more rapid evacuation of water from above the frost table. Data were collected from 24 shallow screened wells. 2 replicate rows of 4 wells were located at: (a) a hillslope (HS) ~120m away from the gully TK, (b) perpendicular to the gully TK (TK) and (c) perpendicular to an unimpacted water track (WT) upstream of the gully TK. Note that water levels are the distance below the ground surface and may have organic/peat layers of different thicknesses.
File contains temperature and discharge data for Lake NE 14 Outlet during the 2010 summer field season.
File contains temperature and discharge data for lake NE 14 Outlet during the 2009 summer field season.
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.
The (ARCSSTK) did extensive research during 2009-2011 field seasons in Arctic Alaska. The objective of this data set was to measure the quantity and biodegradability of DOC from headwater streams and rivers across three geographic regions and across four natural ‘treatments’ (reference; thermokarst-; burned-, and thermokarst + burned-impacted streams) to evaluate which factors most strongly influence DOC quantity and biodegradablity at a watershed scale.
The (ARCSSTK) did extensive research during 2009-2011 field seasons in Arctic Alaska. The objective of this data set was to measure the quantity and biodegradability of DOC from headwater streams and rivers across three geographic regions and across four natural ‘treatments’ (reference; thermokarst-; burned-, and thermokarst + burned-impacted streams) to evaluate which factors most strongly influence DOC quantity and biodegradablity at a watershed scale. This table provides physical site characteristics for the locations sampled for stream water biodegradability.
GroMeteorological parameters were measured hourly adjacent to thermokarst features in the region around Toolik Field Station. Pressure, rainfall, wind speed and direction, solar radiation, air temperature and relative humidity were all measured at 1-3m above the ground surface with an Onset U30 weather station connected to all sensors.
Ground temperatures were measured hourly at ~20-50cm intervals below the ground surface inside and adjacent to thermokarst features in the region around Toolik Field Station. Ground temperatures were measured using Hobo thermistors. Temperatures at 0 and 20cm depths were measured directly in the ground whereas 40cm and deeper measurements were logged from dry wells installed in summer 2009. NE14_TS02dot02_temp is located in the old NE14 thermokarst, upslope.
Ground temperatures were measured hourly at ~20-50cm intervals below the ground surface inside and adjacent to thermokarst features in the region around Toolik Field Station. Ground temperatures were measured using Hobo thermistors. Temperatures at 0 and 20cm depths were measured directly in the ground whereas 40cm and deeper measurements were logged from dry wells installed in summer 2009. TRTK_GT01dot05_temp is located outside the TRTK thermokarst, midslope.
Ground temperatures were measured hourly at ~20-50cm intervals below the ground surface inside and adjacent to thermokarst features in the region around Toolik Field Station. Ground temperatures were measured using Hobo thermistors. Temperatures at 0 and 20cm depths were measured directly in the ground whereas 40cm and deeper measurements were logged from dry wells installed in summer 2009. IM2_GT01dot06_temp is located inside of the I-Minus-2 Gulley thermokarst, downslope.
Hourly data from the Toolik Moist Non-acidic Tussock Experimental plots (MNT). In 1999 a Campbell CR10x data logger was installed in block 2 of the experimental plots. The plots are located on a hillside near Toolik Lake (68 38' N, 149 36'W). Sensors were placed in control and greenhouse sites. Soil temperature profiles are reported in another file (1999-present_MNTsoil).
This is a study of how different snow regimes effect CO2 exchange in tussock tundra and whether there are shifts in ecosystem C cycling when facets of "drift" effects are isolated. The study is part of the IPY program and is aimed at measuring the state of Arctic tundra.
This is a study of how different snow regimes effect CO2 exchange in tussock tundra and whether there are shifts in ecosystem C cycling when facets of "drift" effects are isolated. The study is part of the IPY program and is aimed at measuring the state of Arctic tundra.
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 Artic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of throughflow, 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. There were a number of TASCC and Plateau nutrient additions at each sampling location.
The Changing Seasonality of Arctic Stream Systems (CSASN) did extensive arctic stream research from 2010 to 2012. Specifically, 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 determine how these influences will shift under seasonal conditions that are likely to be substantially different in the future. Throughout the project, samples were collected from Benthic Rock Scrubs and Fine Benthic Organic Matter (FBOM).
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. There were a number of TASCC and Plateau nutrient additions at each sampling location.
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 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. There were a number of tracer addition for spiraling curve characterization (TASCC) and Plateau nutrient additions at each sampling location.
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. Throughout the project, samples were collected from Benthic Rock Scrubs and measured for cholorophyll-a and particulate carbon (C), nitrogen (N) and phosphorus (P).
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.
Relative percent cover was measured for plant species on Arctic LTER experimental plots at Toolik field station in moist acidic and moist non acidic tussock tundra, and dry heath tundra, and on Sagavanirktok River toposequence plots in tussock and heath tundra.
Relative percent cover was measured for plant species on Arctic LTER experimental plots in moist acidic and moist non-acidic tundra, Toolik Field Station, Alaska, Arctic LTER 1999.
We deployed three eddy covariance towers along a burn severity gradient (i.e. severely-, moderately-, and un-burned tundra) to monitor post fire Net Ecosystem Exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar during the summer of 2008. This data represents the 2009 post fire energy and mass exchange at the severe burn site.
We deployed three eddy covariance towers along a burn severity gradient (i.e. severely-, moderately-, and un-burned tundra) to monitor post fire Net Ecosystem Exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar during the summer of 2008. This data represents the 2012 post fire energy and mass exchange at the moderate burn site.
We deployed three eddy covariance towers along a burn severity gradient (i.e. severely-, moderately-, and un-burned tundra) to monitor post fire Net Ecosystem Exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar during the summer of 2008. This data represents the 2011 post fire energy and mass exchange at the moderate burn site.
We deployed three eddy covariance towers along a burn severity gradient (i.e. severely-, moderately-, and un-burned tundra) to monitor post fire Net Ecosystem Exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar during the summer of 2008. This data represents the 2010 post fire energy and mass exchange at the unburned site.
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.
Relative percent cover was measured for plant species on Arctic LTER experimental plots at Toolik field station in moist acidic and moist non acidic tussock tundra, and dry heath tundra.
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.
We deployed three eddy covariance towers along a burn severity gradient (i.e. severely-, moderately-, and un-burned tundra) to monitor post fire Net Ecosystem Exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar during the summer of 2008. This data represents the 2009 post fire energy and mass exchange at the unburned site.