The North American Arctic Transect: Patterned-Ground Ecosystems Across the Full Arctic Bioclimate Gradient
Abstract
We studied the ecosystems related to small patterned-ground features at 12 locations along an 1800-km long transect in the western North American Arctic. We examined permafrost-soil-vegetation relationships from treeline to the extreme High Arctic (bioclimate subzones A to E on the Circumpolar Arctic Vegetation Map; 10 degrees of latitude, Toolik Lake, Alaska to Isachsen, Canada and approximately 11 degrees C of mean July temperature). Here we present some of the early results that demonstrate the intimate relationship between climate, vegetation, soil type, and patterned-ground morphology. Frost heave, up to 21 cm in the centers of non-sorted circles, is strongest in silty soils. Modeling the processes involved in small-patterned-ground formation focuses on the flow of heat and water within the features in relationship to the differential heat flux at the soil surface. Cryoturbation redistributes carbon in the soil profiles, and much of this becomes sequestered in frozen organic horizons at the permafrost table. The amount of carbon in the permafrost varies considerably depending on the climate regime and the patterned-ground form. Microbiotic crusts are common on the surface of patterned-ground features and are likely early sources of nitrogen fixation in vegetation succession. The transect now provides a baseline of observations along the complete Arctic climate gradient including ecosystems at the cold extreme and should be considered for long-term observations and monitoring related to the International Polar Year.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFM.C24A..03W
- Keywords:
-
- 0700 CRYOSPHERE (4540);
- 0706 Active layer;
- 0710 Periglacial processes;
- 0718 Tundra (9315);
- 0793 Biogeochemistry (0412;
- 0414;
- 1615;
- 4805;
- 4912)