382
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
to 1234 m, while the shoreline area has gentle morphology. The catchment area is large at 6210
km 2 (Bogdanov, 1985).
The structure and composition of vegetation are not uniform. Vegetation in the immediate
Lama Lake surrounding is dense and dominated by shrubs, birch and Taiga trees (larch and less
spruce). In the grass-dwarf-shrub layer, grass prevails and blueberry is abundant, and alder
and willow dominate in the brushwood. The treeline passes at an altitude between 200 and 400
m a.s.I. The altitudinal succession is not transitional but rather patchy.
Above the tree line, initial soil development is observed while in lower elevations with a
closed vegetation cover brown soils were found. In depressions and on beach terraces peat
formation (hummocky tundra) occurs (A. Raab, pers. comm.).
Lama Lake has its largest inflow on the northern shore, NW of the sediment sampling site.
The lake shore reaches up to 10m in width and is covered with pebbles, gravel and some sand
due to the high annual lake level fluctuation (up to 4 m). During high lake level periods,
vegetation near the shoreline is submerged. Sparsely distributed macrophytes (Chara sp.) have
been observed in well illuminated places.
Temperature profiles (in Figure 2) suggest a thermal regime within the transition from
subpolar dimictic to polar monomictic type. The ice free period persists only from early July
until late October (Bogdanov, 1985).
The annual maximum of biomass production of the Putoran lakes occurs in fall
(August/September) (Aleksyuk and Bekman, 1981; Chernyaeva, 1981; Shur and Sid'ko,
1985).
According to chemical and hydrological measurements, the lake water is slightly alkaline
(Melles et aI., 1994), considered to derive from the basaltic bedrock which covers the whole
catchment area. Together with the high water volume, this gives the lake a high buffering
capacity against external inputs. Conductivity values are around 85 IlS/cm. Since the
development of the Norilsk smelter complex in the 1930s, concentrations of Cd, Cu, Ni, Pb
and Zn in the lake sediments show a progressive increase (Hagedorn et aI., this volume).
Results
Diatom record
Diatoms in the sequence are first recorded from a sample taken at 6.68 m sediment depth.
Relying on the palynological zonation (Hahne and Melles, this volume; Hahne and Melles,
1997), this first record is placed within the Younger Dryas period.
Over 200 diatom taxa were identified in the Lama Lake core PG 1111 (maximum 91 species per
sample). Such species-rich assemblages are typical for oligotrophic boreal lakes (e.g. Pienitz
and Smol, 1993; Pienitz et aI., 1995a; Lange-Bertalot and Metzeltin, 1996). Relative
frequencies of the important species are presented in Figures 3 A and B. The Lama Lake
sequence is split into eight local diatom assemblage zones (DAZ; see Table 2 and Figure 4).
Diatom assemblage zones (* marks species maxima)
Small centric diatom taxa dominated the diatom assemblages in the Lama Lake sequence.
Cyclotella comensis was the most abundant diatom species in the sequence associated with
Cyclotella gordonensis and Cyclotella cf. kuetzingiana var. radiosa. Changes in the main
constituents of the planktonic group were remarkable, especially in the lower part of the
sequence. In the first assemblages (DAZ-l), Cyclotella rossii (*) was the most abundant
planktonic diatom co-occurring with frequent Aulacoseira islandica (*). Subsequently, in
(DAZ-2), a maximum abundance of C. gordonensis (*) was observed. In DAZ-3, the
proportions of Cyclotella comensis and Cyclotella cf. kuetzingiana var. radiosa increased. A
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
to 1234 m, while the shoreline area has gentle morphology. The catchment area is large at 6210
km 2 (Bogdanov, 1985).
The structure and composition of vegetation are not uniform. Vegetation in the immediate
Lama Lake surrounding is dense and dominated by shrubs, birch and Taiga trees (larch and less
spruce). In the grass-dwarf-shrub layer, grass prevails and blueberry is abundant, and alder
and willow dominate in the brushwood. The treeline passes at an altitude between 200 and 400
m a.s.I. The altitudinal succession is not transitional but rather patchy.
Above the tree line, initial soil development is observed while in lower elevations with a
closed vegetation cover brown soils were found. In depressions and on beach terraces peat
formation (hummocky tundra) occurs (A. Raab, pers. comm.).
Lama Lake has its largest inflow on the northern shore, NW of the sediment sampling site.
The lake shore reaches up to 10m in width and is covered with pebbles, gravel and some sand
due to the high annual lake level fluctuation (up to 4 m). During high lake level periods,
vegetation near the shoreline is submerged. Sparsely distributed macrophytes (Chara sp.) have
been observed in well illuminated places.
Temperature profiles (in Figure 2) suggest a thermal regime within the transition from
subpolar dimictic to polar monomictic type. The ice free period persists only from early July
until late October (Bogdanov, 1985).
The annual maximum of biomass production of the Putoran lakes occurs in fall
(August/September) (Aleksyuk and Bekman, 1981; Chernyaeva, 1981; Shur and Sid'ko,
1985).
According to chemical and hydrological measurements, the lake water is slightly alkaline
(Melles et aI., 1994), considered to derive from the basaltic bedrock which covers the whole
catchment area. Together with the high water volume, this gives the lake a high buffering
capacity against external inputs. Conductivity values are around 85 IlS/cm. Since the
development of the Norilsk smelter complex in the 1930s, concentrations of Cd, Cu, Ni, Pb
and Zn in the lake sediments show a progressive increase (Hagedorn et aI., this volume).
Results
Diatom record
Diatoms in the sequence are first recorded from a sample taken at 6.68 m sediment depth.
Relying on the palynological zonation (Hahne and Melles, this volume; Hahne and Melles,
1997), this first record is placed within the Younger Dryas period.
Over 200 diatom taxa were identified in the Lama Lake core PG 1111 (maximum 91 species per
sample). Such species-rich assemblages are typical for oligotrophic boreal lakes (e.g. Pienitz
and Smol, 1993; Pienitz et aI., 1995a; Lange-Bertalot and Metzeltin, 1996). Relative
frequencies of the important species are presented in Figures 3 A and B. The Lama Lake
sequence is split into eight local diatom assemblage zones (DAZ; see Table 2 and Figure 4).
Diatom assemblage zones (* marks species maxima)
Small centric diatom taxa dominated the diatom assemblages in the Lama Lake sequence.
Cyclotella comensis was the most abundant diatom species in the sequence associated with
Cyclotella gordonensis and Cyclotella cf. kuetzingiana var. radiosa. Changes in the main
constituents of the planktonic group were remarkable, especially in the lower part of the
sequence. In the first assemblages (DAZ-l), Cyclotella rossii (*) was the most abundant
planktonic diatom co-occurring with frequent Aulacoseira islandica (*). Subsequently, in
(DAZ-2), a maximum abundance of C. gordonensis (*) was observed. In DAZ-3, the
proportions of Cyclotella comensis and Cyclotella cf. kuetzingiana var. radiosa increased. A