Bolvansky

Created: 2014-01-28 16:49:17
Modified: 2014-01-28 16:49:17

SITE DESCRIPTION

The Bolvansky CALM site (68 17.30N; 54 30.00E) is located in the Pechora River Delta, on the northernmost extremity of Cape Bolvansky, which juts into the Pechora Inlet. The Bolvansky weather station operated on the Cape from 1935 to 1997. Long-term MAAT is 4.4 C and mean annual precipitation is 404 mm. The Cape is an undulating plain with numerous lake depressions and large flat-bottom valleys, some of them with permanent creeks. Elevations range from 20 to 35m a.s.l. The surficial material is a boulder sandy loam of Quaternary age exceeding 100m in thickness. Depressions are occupied by polygonal peatlands and fens with peat thickness ranging from 0.5 to 5m. The area is geocryologically unstable due to its position at the western extremity of the continuous permafrost zone. Permafrost develops under convex and flat surfaces, whereas the permafrost table is deeper in valleys, both dry and drained by streams. Data from numerous boreholes show that open taliks occur under the Pechora valley and beneath many lakes (Ershov, 1988). The Bolvansky grid contains 121 sampling nodes and occupies the top of a hill with gentle slopes.Dwarf shrub/lichen tundra with tundra circles (frost boils) occupies the site. The site contains three boreholes. Permafrost temperature at the depth of zero annual temperature amplitude (10 to 12 m) is 2.1 C. in a borehole located in the central and highest point of the site. The range of elevations within the site is 5m. Organic (peaty) soil layer thickness reaches 22 cm at some grid nodes, whereas the site average is only 5 cm. Lower soil horizons are developed in gravelly sandy loam. Volumetric water content of the loam ranges mostly from 30 to 40%; generally, the thicker an organic layer, the higher the water content (Mazhitova et al., 2004).

SAMPLING DESIGN AND METHOD:

1-ha grid consists of a square array of surveyed permanent stakes separated by 10 m, yielding an 11 × 11 array of sampling nodes on each grid. Thaw depth and snow sampling was conducted twice by manual probing at each stake. The two values for each sampling point are averaged, yielding a maximum of 121 data points per grid per probing date. The active layer was not measured at locations where grid points intersect rocks or deep water.