A vegetation, climate and environment reconstruction based on palynological analyses of high arctic tundra peat cores (5000–6000 years BP) from Svalbard

Abstract

Photo. Arctic tundra peat in front of Stuphallet, Brøggerhalvøya, not far from Ny Alesund.Nutrient enrichment by nesting seabirds at the steep rocks of Stuphallet stimulates growth of many arctic plants. Because of the permafrost at 15 -20 cm below ground level, and soil melt-water in the summer period, the wet tundra soil is waterlogged. A peat profile was sampled with a depth of 105 cm using a motor-driven soil corer with a saw-tooth end. Photograph by J. Rozema. AbstractAs a reference for ongoing studies reconstructing past vegetation, climate and environment, pollen spectra in tundra peat profiles from Svalbard, were investigated. The base of tundra peat cores collected from Ny Å lesund, Stuphallet, Blomstrand and Isdammen has been 14 C dated to 350 -490 BP, 5710 BP, 4670 BP and 700 -900 BP, respectively. The Stuphallet and Blomstrand (Brøggerhalvøya) peat profiles were composed of a peat developed in a nutrient enriched and wet tundra environment of steep birdcliffs. Pollen concentrations were low, Brassicaceae pollen dominated the whole profile. In contrast, the Ny Å lesund and Isdammen profiles contained high pollen concentrations and suggest a nutrient-poor, dry tundra environment. Pollen of the polar willow, Salix polaris, occurred commonly throughout all four peat profiles. In the relatively high resolution (10 years per peat core sample) analysis of the Ny Å lesund core, starting before or at the beginning of the Little Ice Age (LIA, 16th-mid 19th century), dominance of Saxifraga oppositifolia indicates a cold and dry climate, followed by a decline of Saxifraga oppositifolia and gradual increase of Salix polaris after the LIA, which indicates a moist and milder climate.

What do Holocene sediments in Petuniabukta, Spitsbergen reveal?

“…In contrast, macrofossil analysis had been conducted only in a few cases (Birks 1991;van der Knaap 1985). There have been only a few palaeoecological studies from Svalbard published in the last decade, which is surprising given the interest in Arc− tic climate change and palaeoenvironmental change (Isaksson et al 2003;Rozema et al 2006). Van der Knaap (1988c, 1989 suggest that the vegetation of Svalbard was mod− erately rich in species before ca 4000 BP, supporting a similar observation made by Birks (1991).…”

“…Species richness at the lower part of a sediment core collected from Skadjørna lake (dated to ca to 8 000 to 4 000 cal yr BP) was higher than in the upper parts (Birks 1991). Vegetation, dominated mostly by Brassicaceae and Cyperaceae pollen, was found on nutrient−rich sites such as bird cliffs or skua mounds, accompa− nied with Salix polaris pollen during warmer and wetter climate and with pollen of Saxifraga oppositifolia during colder and drier periods (Rozema et al 2006;van der Knaap 1988a, b). Van der Knaap (1985) found nutrient−enriched soils in the area of Smeerenburg inhabited by Dutch whalers.…”

“…A warmer than present climate during the early and mid−Holocene enabled some thermophilous species (e.g. Mytilus edulis, Salix herbacea) to spread northwards and/or deeper in the inner part of the island respectively (Rozema et al 2006;. Gradual cooling accompanied by the advance of glaciers began around 2 800 cal yr BP and culminated in the Little Ice Age (LIA) dated to 700-100 cal yr BP (Elverhoi et al 1995;Szczuciński et al 2009).…”

Using Available Information to Assess the Potential Effects of Climate Change on Vegetation in the High Arctic: North Billjefjorden, Central Spitsbergen (Svalbard)

“…The area of Billefjorden was completely deglaciated about 11 200-11 300 years before present (BP) (Szczucinski et al 2009), at the beginning of the Holocene, and there is no evidence for large-scale re-glaciation since then. Ice-core records together with pollen and marine mollusc data indicate that the climate from 9500 to 4000 years BP was approximately 1-2°C warmer than today (Rozema et al 2006;Svendsen and Mangerud 1997). This warm period was confirmed in a study of macrofossils (Birks 1991), which inferred a warmer climate 8000-4000 years BP with denser and more luxuriant vegetation than today and with species not currently occurring in the area.…”

“…Gradual cooling accompanied by glacier expansion began about 2800 years BP and culminated in the LIA dated to 700-100 years BP (Elverhoi et al 1995;Szczucinski et al 2009). In pollen profiles, a decrease in species richness during the LIA was observed (Rozema et al 2006;Van der Knaap 1987, 1988, 1990, although the vegetation composition according to pollen and macrofossil analyses on Svalbard was rather stable in that time. Hyvarinen (1970) found an assemblage of vegetation that resembled the current assemblage of vegetation in a core dated to 11 000 years BP from basal sediments in north Svalbard.…”