344
Land-Ocean Systems in the Siberian Arctic: Dvnamics and History
6000 with Flame Ionisation Detector [FID] and Temperature Conductivity Detector [WLD],
Fisons Company). For detailed description see Samarkin et al. 1997. Soil temperatures at
various depths were continuously monitored by means of thermistors connected to data loggers
(Grant, Great Britain). Water table position was investigated by boreholes.
Investigation area
Lake Levinson Lessing is located in the southern part of the Byrranga Mountains in northern
Taymyr Peninsula, Central Siberia (75°32'N, 98°35'E, see Figure. I). The region is dominated
by a cold-continental climate (mean annual air temperature: -15°C, mean July air temperature:
6.6°C, mean annual precipitation: < 281 mm, climate reports from "Taymyr Lake Station"
1963-1992, amount of days> O°C: about 50, own observations during summer 1996).
Soils
The Levinson Lessing-region is dominated by weakly developed and wet soils, strongly
influenced by cryoturbation and their position in the micro- and macrorelief.
The valley of the Krasnaya-River is covered by ice-wedge polygons with an accumulation of
weakly decomposed plant material and wet soils of loamy-sandy sediments (Soil Taxonomy:
Histic Pergelic Cryaquepts, Pergelic Cryofibrists; compare Gundelwein et ai., 1997). The
microrelief of the ice-wedge polygons is characterized as depression (wet polygon centre
depression) and as apex (dry polygon rise, see also Figure. 2). The polygon diameters range
between 5-25 m, the apexes with underlying ice wedges are 10 to 60 cm high. About 34 % of
the polygon area are apexes, 66 % are depressions. The main soil parameters of the investigated
polygon site are presented in Tables 1 and 2. A more detailed description can be found in
Gundelwein et al. (1997) and Pfeiffer et al. (1996).
Vegetation
The main vegetation is characterized by a typical wet tundra in the typical tundra belt of Taymyr
Peninsula (Aleksandrova, 1980). The vegetation of the polygon depressions is dominated by
vascular plants like Carex stans and Dupontia fisheri and by mosses like Plagomnium elatum
and Drepanocladus uncinatus. Mosses have a coverage of 100 %, whereas vascular plants
cover 80 % of soil surface. On moderately high polygon apexes vegetation shows an
increasing rate of dwarf shrubs, especially Dryas punctata, accounting for a total of 35 %
coverage. Total vascular plant cover here is 55 %, whereas mosses account for 95 %.
Tormenthypnum nitens dominates, representing as much as 75 % coverage.
Results
Microclimate
During the field-season from July 20th to August 15th a warm period was followed by cool,
cloudy and humid weather. Average ambient temperature during the field-stay was 8°C,
maximum and minimum were 20°C and 1 DC, respectively. Microclimate of the polygonal tundra
showed differences between polygon trough and polygon apex. Surface temperature at the apex
was up to 10°C higher than at the depression. Temperature in the deeper soil horizons tended to
be somewhat more homogenous at the polygon depression than at the apex. The water table
position was higher at the polygon depression than at the apex area. The water table at the
depression was never found deeper than 7 cm below soil surface, whereas it was observed as
deep as 14 cm at the apex. During a heavy rain fall event on August 6th, the water table at the
Land-Ocean Systems in the Siberian Arctic: Dvnamics and History
6000 with Flame Ionisation Detector [FID] and Temperature Conductivity Detector [WLD],
Fisons Company). For detailed description see Samarkin et al. 1997. Soil temperatures at
various depths were continuously monitored by means of thermistors connected to data loggers
(Grant, Great Britain). Water table position was investigated by boreholes.
Investigation area
Lake Levinson Lessing is located in the southern part of the Byrranga Mountains in northern
Taymyr Peninsula, Central Siberia (75°32'N, 98°35'E, see Figure. I). The region is dominated
by a cold-continental climate (mean annual air temperature: -15°C, mean July air temperature:
6.6°C, mean annual precipitation: < 281 mm, climate reports from "Taymyr Lake Station"
1963-1992, amount of days> O°C: about 50, own observations during summer 1996).
Soils
The Levinson Lessing-region is dominated by weakly developed and wet soils, strongly
influenced by cryoturbation and their position in the micro- and macrorelief.
The valley of the Krasnaya-River is covered by ice-wedge polygons with an accumulation of
weakly decomposed plant material and wet soils of loamy-sandy sediments (Soil Taxonomy:
Histic Pergelic Cryaquepts, Pergelic Cryofibrists; compare Gundelwein et ai., 1997). The
microrelief of the ice-wedge polygons is characterized as depression (wet polygon centre
depression) and as apex (dry polygon rise, see also Figure. 2). The polygon diameters range
between 5-25 m, the apexes with underlying ice wedges are 10 to 60 cm high. About 34 % of
the polygon area are apexes, 66 % are depressions. The main soil parameters of the investigated
polygon site are presented in Tables 1 and 2. A more detailed description can be found in
Gundelwein et al. (1997) and Pfeiffer et al. (1996).
Vegetation
The main vegetation is characterized by a typical wet tundra in the typical tundra belt of Taymyr
Peninsula (Aleksandrova, 1980). The vegetation of the polygon depressions is dominated by
vascular plants like Carex stans and Dupontia fisheri and by mosses like Plagomnium elatum
and Drepanocladus uncinatus. Mosses have a coverage of 100 %, whereas vascular plants
cover 80 % of soil surface. On moderately high polygon apexes vegetation shows an
increasing rate of dwarf shrubs, especially Dryas punctata, accounting for a total of 35 %
coverage. Total vascular plant cover here is 55 %, whereas mosses account for 95 %.
Tormenthypnum nitens dominates, representing as much as 75 % coverage.
Results
Microclimate
During the field-season from July 20th to August 15th a warm period was followed by cool,
cloudy and humid weather. Average ambient temperature during the field-stay was 8°C,
maximum and minimum were 20°C and 1 DC, respectively. Microclimate of the polygonal tundra
showed differences between polygon trough and polygon apex. Surface temperature at the apex
was up to 10°C higher than at the depression. Temperature in the deeper soil horizons tended to
be somewhat more homogenous at the polygon depression than at the apex. The water table
position was higher at the polygon depression than at the apex area. The water table at the
depression was never found deeper than 7 cm below soil surface, whereas it was observed as
deep as 14 cm at the apex. During a heavy rain fall event on August 6th, the water table at the