Late quaternary ecological turnover in high arctic lake einstaken, nordaustlandet, svalbard (80° n)

Abstract

Multiproxy palaeolimnological analyses of a sediment core record from Lake Einstaken, Nordaustlandet, give insight into long-term ecological and environmental dynamics in the High Arctic Svalbard during the last c. 13 000 cal yr BP. Fossil remains of foraminifera, chironomidae, cladocera and diatoms (Bacillariophyta) revealed several distinct ecological turnovers during the late Quaternary. The foraminiferal assemblages in a marine interval in the lower part of the core indicated one distinct faunal turnover and two subsequent minor changes. The foraminiferal assemblages reflected high-arctic, shallow-water conditions in an area of changing salinity conditions. A development of gradually more restricted marine conditions, presumably related to a decrease in water depth during the isostatic uplift, was evident from the foraminiferal assemblages. The Holocene was characterized by a freshwater environment in the isolated Lake Einstaken. The cladoceran assemblages experienced two complete faunal turnovers in the early part of the lacustrine sediment sequence, most likely related to inlake processes. The chironomid assemblages went through five distinct Holocene faunal changes that were probably mostly related to climate development and changes in nutrient conditions. The freshwater diatoms revealed four distinct episodes of change in their assemblages that could be related to their sensitivity to pH and nutrient status. The most distinct common feature in the Holocene faunal and floral assemblages was the pioneer phase during the early Holocene. The recent environmental changes, which were most visibly reflected in the chironomid records, are possibly related to a coupled effect of elevated nutrient conditions and increased temperatures.

Holocene sedimentary environment of a High−Arctic fjord in Nordaustlandet, Svalbard

“…It is somewhat younger than the age of deglaciation of the surrounding higher grounds, i.e. 12,400 cal BP (Luoto et al 2011). Above this, the next two calibrated AMS 14 C ages lie at depths of 175-169 and 150-153 cm, and these are dated to 7190±60 cal BP and 5775±75 cal BP, respectively, providing a sedimentation rate of 12.4-16.3 cm ka −1 for the lower part of the sequence.…”

“…15,000 cal BP (Koç et al 2002;Ślubowska et al 2005). The deglaciation initially proceeded slowly and the catchment of Isvika bay was free of ice at around 12,400 cal BP (Luoto et al 2011). Following this, the surface waters opened in Hinlopen Strait at ca.…”

“…Sea ice usually covers the fjord from October to June but there are marked year−to−year variations. Tidal currents were observed to raft icebergs to Murchisonfjorden through Hinlo− penstretet in the summer of 2007 and 2009. The area was deglaciated during the Younger Dryas Stadial, 12,400-11,500 years ago (Kaakinen et al 2009;Kubischta et al 2011;Luoto et al 2011). The landscape has a smoothly rolling topography, mostly covered by weathered rock debris.…”

Invertebrate communities of the High Arctic ponds in Hornsund

“…The reason why B. longirostris is missing from Coastal pond is most likely related to planktonic food web competition with D. pulex as these taxa share a similar ecological niche. The alternate and exclusive success be− tween Daphnia and Bosmina is typical for the relatively simple aquatic food webs in Svalbard (Guilizzoni et al 2006;Luoto et al 2011). …”

Gomphonema svalbardense sp. nov., a new freshwater diatom species (Bacillariophyta) from the Arctic Region

“…During more recent years, diatom studies on Svalbard were restricted to a few sparse floristic and (paleo-)ecological accounts (e.g., Picińska-Fałtynowicz 1988, Beyens 1989, Van de Vijver et al 1999, Guilizzoni et al 2006, Luoto et al 2011 and only a few new taxa were described from the archipelago. Van de Vijver et al (2004) described three new Stauroneis taxa from Svalbard in their revision of this genus in the Arctic and Antarctic Regions.…”