Data Set Results

Displaying 101 - 150 of 213

Leaf area for select species was measured in arctic tundra experimental sites from late June into early August,Toolik Field Sattion, Alaska, Arctic LTER 2000.

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),1982.

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.

Phenological stages of sedges were observed at a long term experimental moist tussock tundra site and a long-term experimental wet sedge tundra sites (Arctic LTER) for 1996 near Toolik Lake, AK.

Phenological stages of sedges were observed at a long term experimental moist tussock tundra site and a long-term experimental wet sedge tundra sites near Toolik Lake, AK. Also, ITEX maximum growth measurements were recorded on August 19th (moist tussock tundra). Experimental treatments at each site included factorial NxP, greenhouse and shadehouse and were begun in 1989. See 96gsphdc.html and 96gsphsg.html for phenological data on deciduous and evergeen species.

Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska.

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.

Plant biomass in heath tundra experimental plots, 1996, Arctic LTER, Toolik Lake, Alaska.

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.

Plant biomass in moist acidic tussock tundra experimental small mammal exclosures, 1999 Arctic LTER Toolik, Alaska.

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.

Seasonal plant biomass moist acidic tussock tundra, 1983, Arctic LTER, Toolik Lake, Alaska.

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), 1982.

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.

Plant biomass, leaf area, carbon, nitrogen, and phosphorus in wet sedge tundra, 1994, Arctic LTER, Toolik Lake, Alaska.

Plant biomass, leaf area, carbon, nitrogen, and phosphorus were measured in three wet sedge tundra experimental sites. Treatments at each site included factorial NxP and at the Toolik sites greenhouse and shade house. Treatments started in 1985 (Sag site) and in 1988 (Toolik sites).

Characterization of burned and unburned moist acidic tundra sites for estimating C and N loss from the 2007 Anaktuvuk River Fire, sampled in 2008.

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.

Data on weights and lengths from retrospective growth analysis of different stem age classes of Betula nana ramets from the Arctic LTER Nutrient and Warming manipulations in mosit acidic tussock tundra at 1995, Toolik Lake, AK.

This data file contains the data on weights and lengths from retrospective growth analysis of different stem age classes of Betula nana ramets from the Arctic LTER Nutrient and Warming manipulations in moist acidic tussock tundra at Toolik Lake.

Weights and lengths from retrospective growth analysis of different stem age classes of Betula nana, 1995, Arctic LTER, Toolik Lake, Alaska.

This data file contains the data on weights and lengths from retrospective growth analysis of different stem age classes of Betula nana ramets from the LTER Nutrient and Warming manipulations in tussock tundra at Toolik Lake.

Above ground plant biomass in a mesic acidic tussock tundra experimental site 2000, Arctic LTER, Toolik Lake, Alaska.

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(1), 1991 pp.1-31.) This file contains the biomass numbers for each harvested quadrat and per cent carbon and nitrogen summaries for control and fertilized plots. Leaf area data is in 2000gsttLA

Above ground plant biomass in a mesic acidic tussock tundra experimental site from 1982 to 2000 Arctic LTER, Toolik Lake, Alaska.

Above ground plant biomass and leaf area were measured in a moist acidic tussock tundra experimental site. The plots were set up in 1981 and have been harvested in periodical (See Shaver and Chapin Ecological Monographs, 61(1), 1991 pp.1-31. Mack, et al, Nature 2004 431:440-443) This file contains the biomass numbers for each harvested quadrat and per cent carbon and nitrogen summaries for harvests through 2000. Leaf area data is presented in other data files (see http://ecosystems.mbl.edu/arc).

Anaktuvuk River fire scar thaw depth measurements during the 2008 to 2014 growing season

The Anaktuvuk River Fire occurred in 2007 on the North Slope of Alaska. In 2008, three eddy covariance towers were established at sites represent ing unburned tundra, moderately burned tundra, and severely burned tundra. Several times during the 2008-2014 growing seasons, thaw depth was measured at approximately 70 points near each of these towers . Data presented here are the individual measurements for each site and date.

Numbers of Eriophorum vaginatum inflorescences, both unclipped and clipped by small mammals, were counted in experimental small mammal exclosure plots, Arct LTER mosit acidic tussock site, Toolik Field Station, Alaska, 1997 to present.

Numbers of Eriophorum vaginatum inflorescences, both unclipped and clipped by small mammals, were counted in experimental plots. The plots are setup in moist acidic tussock tundra near Toolik Field Station, Alaska ((8 degrees 37' 27" N, 149 degrees 36' 27"W) and include fenced exclosures in both fertilized and unfertilized tundra.

Phenological stages of deciduous plants were observed at a long term experimental moist acidic tussock tundra site, Arctic LTER 1996 Toolik Lake, AK.

Phenological stages of deciduous plants were observed at a long term experimental moist acidic tussock tundra site (Arctic LTER) near Toolik Field Station, AK. Also, ITEX maximum growth measurements were recorded on August 19th (moist tussock tundra). Experimental treatments at each site included factorial NxP, greenhouse and shadehouse and were begun in 1989. See 96gspheg.html and 96gsphsg. html for phenological data on evergreen and sedge species.

Summer soil temperature and moisture at the Anaktuvuk River Moderately burned site from 2010 to 2013

Soil moisture and temperature were recorded at the Anaktuvuk River burn area during the summers from 2010 to 2013. Six sensors were deployed and measured temperature on half-hourly intervals over the summer and into the fall depending on battery function. Sensors were place in a hexagonal shape around a central datalogger. Note that over time sensor depths changed due to frost heave and other environmental factors. All data contained should be treated as suspect where sensors may have been at surface. These sensors were removed August 20, 2013, no replacement sensors were installed.

Summer soil temperature and moisture at the Anaktuvuk River Unburned site from 2010 to 2013

Summer soil temperature and moisture at the Anaktuvuk River Severely burned site from 2010 to 2013

Soil moisture and temperature were recorded at the Anaktuvuk River burn area during the summers from 2010 to 2013. Six sensors were deployed and measured temperature on half-hourly intervals over the summer and into the fall depending on battery function. Sensors were place in a hexagonal shape around a central data logger. Note that over time sensor depths changed due to frost heave and other environmental factors. All data contained should be treated as suspect where sensors may have been at surface. These sensors were removed August 20, 2013, no replacement sensors were installed.

Permafrost soil database with information on site, topography, geomorphology, hydrology, soil stratigraphy, soil carbon, ground ice isotopes, and vegetation at thermokarst features near Toolik and Noatak River, 2009-2013

This database contains soil and permafrost stratigraphy associated with thermokarst features near Toolik Lake and the Noatak River collected by Torre Jorgenson and Andrew Balser during summers 2009-2011. The Access Database has main data tables (tbl_) for site (environmental), soil stratigraphy, soil physical data, soil chemical data, soil isotopes (ground ice), soil radiocarbon dates, topography and bathymetry, and vegetation cover.

Above ground plant and below ground stem biomass of samples from the moderately burned site at Anaktuvuk River, Alaska

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.

Summary of below ground root biomass, carbon and nitrogen concentrations from the Anaktuvuk River Fire site in 2011

A summary of below ground root biomass, carbon and nitrogen concentrations, measured at three sites at and around the Anaktuvuk River Burn: severely burned, moderately burned and unburned.

Soil properties and nutrient concentrations by depth from the Anaktuvuk River Fire site in 2011

Below ground soil bulk density, carbon and nitrogen was measured at various depth increments in mineral and organic soil layers at three sites at and around the Anaktuvuk River Burn: severely burned, moderately burned and unburned. This data corresponds with the aboveground biomass and root biomass data files: 2011ARF_AbvgroundBiomassCN, 2011ARF_RootBiomassCN_byDepth, 2011ARF_RootBiomassCN_byQuad, 2011ARF_RootBiomassCN_byQuad.

Above ground plant and below ground stem biomass of samples from the severely burned site of the Anaktuvuk River fire, Alaska

Below ground soil carbon and nitrogen concentrations in quadrats harvested from the Anaktuvuk River Fire site in 2011

Summarized below ground soil carbon and nitrogen concentrations measured in quadrats at three sites at and around the Anaktuvuk River Burn: severely burned, moderately burned and unburned. This data corresponds with the aboveground biomass and root biomass data files: 2011ARF_AbvgroundBiomassCN, 2011ARF_RootBiomassCN_byDepth, 2011ARF_RootBiomassCN_byQuad, 2011ARF_SoilCN_byDepth.

Below ground root biomass, carbon and nitrogen concentrations by depth increments from the Anaktuvuk River Fire site in 2011

Below ground root biomass was measured by depth increments at three sites at and around the Anaktuvuk River Burn: severely burned, moderately burned and unburned. Roots were also analyzed for carbon and nitrogen concentrations.

Above ground plant and below ground stem biomass of samples from the unburned control site near the Anaktuvuk River fire scar.

Sediment primary productivity, respiration and productivity by irradiance curves from lakes near Toolik Field Station 2009 - 2010

Dataset includes rates of benthic gross primary productivity (GPP) in mmol O2/m2/d by irrandiance (I) in uE/m2/s curves and benthic respiration rates in mmol/m2/d from lakes E-5, E-6, Toolik, Fog Lake 2, Horn, Perched and Luna during the summer of 2009-2010.

Methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant communities, Toolik Field Station, North Slope Alaska, Arctic LTER 1991.

Methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant communities.

Above ground plant and below ground stem biomass in the Arctic LTER acidic tussock tundra experimental plots, 2002, Toolik Lake, Alaska.

Above ground plant and below ground stem biomass was measured in the Arctic LTER acidic tussock tundra experimental plots. Treatments included control, nitrogen plus phosphorus amended plots for either 6 or 13 years and vole exclosure plots with or without amends of nitrogen and phosphorus.

Imnavait Watershed Thaw Depth Survey Summary for 2003 to present, Arctic LTER, Toolik Research Station, Alaska.

Thaw depth was measured using a steel probe in the Imnavait Creek watershed, near Toolik Lake, Alaska. The thaw grid includes measurements made from the valley bottom (on both sides of the stream), up the hillslope to the hilltop (watershed boundary). The thaw grid is near Imnavait water tracks 7 and 8, and measurements have been made from the 2003 season until present. Two surveys are conducted each summer, on 2 July and on 11 August (plus or minus 1-2 days on either side of those dates).

Tussock watershed thaw depth survey summary for 1990 to present, Arctic Long-Term Ecological Research (LTER), Toolik Research Station, Alaska.

Thaw depth was measured since 1990 using a steel probe in the Tussock watershed just south of Toolik Lake, Alaska, on a gentle slope dominated by moist, non-acidic tussock tundra. At least two surveys are conducted each summer, on 2 July and on 11 August (plus or minus 1 day).

Anaktuvuk River fire scar eriophorum vaginatum flowering during the 2008-2014 growing seasons

The Anaktuvuk River Fire occurred in 2007 on the North Slope of Alaska. In 2008, three eddy covariance towers were established at sites representing unburned tundra, moderately burned tundra, and severely burned tundra. Eriophorum vaginatum flowers were counted from annual photographs of each site during peak flowering season (6/17-7/20).

Above ground plant biomass and leaf area of moist acidic tussock tundra 1981 experimental site, Arctic LTER, Toolik Lake, Alaska.1995.

Plant leaf area in Arctic LTER tussock tundra experimental small mammal exclosures.

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 a moist acidic tussock tundra experimental site, 1984, Acric LTER, Toolik Lake, Alaska.

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.

Long term response of arctic tussock tundra to thermal erosion features: A modeling analysis. Tussock tundra regrowth after a thermal erosion event: Simulation F - increased N deposition

The Multiple Element Limitation (MEL) model is used to simulate the recovery of Alaskan arctic tussock tundra to thermal erosion features (TEFs) caused by permafrost thaw and mass wasting. TEFs could be significant to regional carbon (C) and nutrient budgets because permafrost soils contain large stocks of soil organic matter (SOM) and TEFs are expected to become more frequent as climate warms. These simulations deal only with recovery following TEF stabilization and do not address initial losses of C and nutrients during TEF formation.