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.
Data Set Results
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.
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.
Late season thaw depth was measured in the Arctic Long Term Ecological Research (ARC LTER) experimental plots (1981 Moist Acidic Tussock, 1989 Moist Acidic Tussock, 2006 Low Fertilization Moist Acidic Tussock, 1989 Moist Non-acidic Tussock, 1989 Moist Non-acidic Non-tussock and 1989 Wet Sedge tundra) at Toolik Lake, Alaska using a steel thaw probe. Note: for 2017-2018 only 1989 Moist Non-Acidic Tussock Tundra and 2006 Low fertilization Moist Acidic Tussock Tundra were measured. For other sites it has become difficult to distinguish rocks from frozen soil with a steel thaw probe.
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.
Methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant communities. This is the third year of collection data.
Methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant communities. This is the second year of collection data.
Methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant communities.
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).
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).
Data file describing the biogeochemistry of samples collected at various sites near Toolik Lake, North Slope of Alaska. Sample site descriptors include a unique assigned number (sortchem), site, date, time, depth, distance (downstream), elevation, treatment, date-time, category, and water type (lake, surface, soil). Physical measures collected in the field include temperature (water, soil, well water), conductivity, pH, average thaw depth, well height, discharge, stage height, and light (lakes).
Data file describing the biogeochemistry of samples collected at various sites near Toolik Lake, North Slope of Alaska. Sample site descriptors include a unique assigned number (sortchem), site, date, time, depth, distance (downstream), elevation, treatment, date-time, category, and water type (lake, surface, soil). Physical measures collected in the field include temperature (water, soil, well water), conductivity, pH, average thaw depth, well height, discharge, stage height, and light (lakes).
Nitrogen mineralization was determined on LTER and Sag River tussock tundra using the buried bag method. Yearly bags have been deployed every August since 1990.
Daily summary of 10 cm soil temperatures in the Arctic LTER moist acidic experimental plots for the control (CT), greenhouse (GH), greenhouse plus nitrogen and phosphorus (GHNP) and nitrogen and phosphorus (NP) plots. Soil temperature probes in the tundra soil were problematic with frost heaving causing the depth of measurements to change. In order to provide a consistent year to year temperature record notes on changes in depths were used to select the temperature sensor that was within + or – 3 cm of the 10 cm and then averaged daily.
Output data sets of the MBL-GEM III model for a typical tussock-tundra hill slope. The model is described in two papers:
Le Dizès, S., Kwiatkowski B.L., Rastetter E.B., Hope A., Hobbie J.E., Stow D., Daeschner S., 2003 Modelling biogeochemical responses of tundra ecosystems to temporal and spatial variations in climate in the Kuparuk River Basin (Alaska), Journal of Geophysical Research Vol. 108 No. D2 10.1029/2001JD000960.
Output data set of the MBL-GEM III model run for tussock tundra in the Kuparuk River Basin, Alaska, described in detail in Le Dizès, S., B. L. Kwiatkowski, E. B. Rastetter, A. Hope, J. E. Hobbie, D. Stow, and S. Daeschner, Modeling biogeochemical responses of tundra ecosystems to temporal and spatial variations in climate in the Kuparuk River Basin (Alaska), J. Geophys. Res., 108(D2), 8165, doi:10.1029/2001JD000960, 2003.
Decadal file describing the water chemistry in various lakes near Toolik Research Station (68 38'N, 149 36'W) during summers from 1990 to 1999. Chemical analyses were conducted on samples from various depths in the sample lakes either once, or multiple times during the spring, summer and fall months (May to September).
Decadal file describing the water chemistry in various lakes near Toolik Research Station (68 38'N, 149 36'W) during summers from 2000 to 2009. Chemical analyses were conducted on samples from various depths in the sample lakes either once, or multiple times during the spring, summer and fall months (May to September).
Note: Corrections were made to Particulate phosphorus values. See version 5 notes.
Decadal file describing the water chemistry in various lakes near Toolik Research Station (68 38'N, 149 36'W) during summers from 1983 to 1989. Chemical analyses were conducted on samples from various depths in the sample lakes either once, or multiple times during the spring, summer and fall months (May to September).
Data file of the biogeochemistry of samples collected at various sites near Toolik Lake, North Slope of Alaska. Sample site descriptors include a unique assigned number (sortchem), site, date, time, depth, distance (downstream from a reference location), elevation, treatment, date-time, category, and water type (lake, surface, soil). Physical measures collected in the field include temperature (water, soil, well water), conductivity, pH, and average thaw depth in soil. Chemical analyses for the sample include alkalinity; dissolved inorganic and organic carbon (DIC and DOC); dissolved gas
Data file describing high frequency (every ~10 minutes), optial sensor-derived chemistry of river water from Oksukuyik Creek near Toolik Field Station, North Slope of Alaska. Data file includes date, time, dissolved organic carbon (DOC) concentration, and nitrate concentration. Sensors (V2 s::can uv-vis spectrophotometers) were continuously deployed from June through August or September and optically determined nitrate and dissolved organic carbon concentrations.
Data file describing high frequency (every ~10 minutes), optial sensor-derived chemistry of river water from Trevor Creek near Toolik Field Station, North Slope of Alaska. Data file includes date, time, dissolved organic carbon (DOC) concentration, and nitrate concentration. Sensors (V2 s::can uv-vis spectrophotometers) were continuously deployed from June through August or September and optically determined nitrate and dissolved organic carbon concentrations.
Data file describing repeated sampling of chemistry of distributed river water from the Kuparuk River, Oksrukuyik Creek, and Trevor Creek watersheds near Toolik Field Station, North Slope of Alaska. Data file includes sampling date, season, sampling point, subcatchment area, and resulting concentrations for a suite of solutes.
We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how explicitly representing grazers versus having grazer effects implicitly aggregated in with other biogeochemical processes in the model alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate from the processes with which they are typically aggregated.
We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how explicitly representing grazers versus having grazer effects implicitly aggregated in with other biogeochemical processes in the model alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate from the processes with which they are typically aggregated.