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.
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.
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).
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.