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Estimates of Arctic Wetland Extent Using Ground Penetrating Radar Stefan Schultheiss 1 ; Christoph E. Geiss 2 ; Phil Camill 5 ; Mark B. Edlund 4 ; Charles E. Umbanhowar 3
Stefan Schultheiss1; Christoph E. Geiss2; Phil Camill5; Mark B. Edlund4; Charles E. Umbanhowar3
1TRICON Geophysik und Systemtechnik GmbH, München, Germany; 2Deptof Physics, Trinity College, Hartford, CT; 3Deptof Biology, St.Olaf College, Northfield, MN; 4St. Croix Watershed Res. Station, Science Museum of Minnesota, Marine on St. Croix, MN; 5Deptof Ecology and Evolutionary Biology, Bowdoin College, Brunswick, ME
Arctic wetlands are an important terrestrial carbon reservoir, a potential sink for atmospheric CO2 as well as a significant source of CH4. We collected approximately 2 km of ground-penetrating-radar profiles across nine wetlands to supplement or borehole-based study of Holocene wetland formation in northern Manitoba. Data were acquired using a SIR-3000 radar unit (Geophysical Survey Systems Incorporated) and analyzed using ReflexW (Sandmeier Scientific Software). All radar profiles clearly show the position of the permafrost horizon between 25 and 50 cm depth as well as the boundary between organic sediment and the underlying glaciofluvial deposits at depths between 1 and 1.5 m. Based on our GPR profiles most wetlands exhibit a simple basin geometry which allows for interpolation between our widely spaced peat cores.
Arctic wetlands play a significant role in the global carbon cycle, but little is known about their response to climate change throughout the Holocene. Our study of Arctic wetlands employs ground-penetrating radar to extend existing borehole data and constrain the geometry of small wetlands. Here we focus on our analyses of five transects from Lake 396, a small glacial lake in northern Manitoba, Canada (59.58°N., -98.57°W).
Fig. 3: Transect 1 – depth to permafrost, base of peatland as well as some deeper structures are indicated. The depth to glacial till is approximately 1 m.
Fig. 4: GPR data for Transect 2
Fig. 5: GPR data for Transect 3
Fig. 1: Location of Lake 396 in northern Manitoba, insert shows location of GPR transects in wetland on NE shore of Lake 396.
Fig. 2: The studied wetland, looking south from the northwestern end of profile T1.
Fig. 6: GPR data for Transect 4
Fig. 7: GPR data for Transect 6
Fig. 8: Depth to glacial sediment for all analyzed profiles.