A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic

Abstract

where changes are expected to be most extensive, so we need to place these projected changes in the context of past Arctic climate variability. We know, from large-scale studies of climate variability over the last century and the last millennium, and from model simulations, that temperature changes tend to be amplified at high latitudes-and this seems to be true both for the periods of 'natural' and of anthropogenic forcing (Moritz et al., 2002; Holland and Bitz, 2003; Arctic Climate Impacts Assessment (ACIA), 2005; see also the discussion at http://www.realclimate.org/index.php?p=234, last accessed 19 October 2007). Palaeoclimatic records from high latitudes may thus capture changes that have affected the hemisphere as a whole, whereas the record is more muted at lower latitudes. This polar amplification is related to feedbacks associated with

Climate-driven shifts in diatom assemblages recorded in annually laminated sediments of Sacrower See (NE Germany)

“…Similarly, Lotter and Birks (1997) examined the thickness of the light and dark layers in the same sequence and explored the effects of nutrients and regional meteorology on seasonal sedimentation. Besonen et al (2008) correlated varve thickness with summer temperatures at an annual resolution for the past millennium. Teranes et al (1999) discussed calcite precipitation in lakes based on geochemical parameters and stable isotopes as well as element ratios of authigenic calcites obtained by sampling of seasonal sediment layers.…”

The chemical development of a hypersaline coastal basin in the High Arctic

“…Therefore, all sufficiently large coastal lakes in the Arctic Archipelago should experience high-conductivity bottom waters (Stewart and Platford 1986). In some freshwater lakes, the annual formation of enriched conductivity water at depth has been noted (Van Hove et al 2006;Besonen et al 2008). At West Lake, Cape Bounty, spring CTD casts reveal bottom waters as high as 0.14 mS cm 21 vs. a column maximum of 0.06 mS cm 21 .…”

Standardization and Calibration of X-Radiographs Acquired with the ITRAX Core Scanner

“…The first main complication arises from the fact that age models are frequently resolved in low time resolution. Nevertheless, annually laminated (varved) sediments yield annually resolved time constrains (Ojala et al 2012), and yet several protocols have been suggested to provide results expressed Petterson et al 1999;Besonen et al 2008). The second complication arises from the density measurement itself.…”