Lake-Sediment Records of Recent Environmental Change on Svalbard: Results of Diatom Analysis

Abstract

* This is the fourth in a series of nine papers published in this special issue dedicated to recent environmental change on Svalbard. H.J.B. Birks, Vivienne J. Jones, and Neil L. Rose were guest editors of this special issue. 31: 445-466, 2004 1 Journal of Paleolimnology AbstractSurface sediments from 23 lakes on Svalbard were analysed for diatoms. 182 taxa were found but samples generally have a low richness, with the majority of sites dominated by benthic genera such as Fragilaria, Navicula, and Achnanthes. Centric Cyclotella species occur at only three sites. Modern relationships between diatom abundance and water chemistry and other environmental variables were explored numerically and a preliminary transfer function for pH was developed. Lakes fell into three groups on the basis of their diatom assemblages: (1) high pH, high cation, high conductivity sites characterised by Amphora libyca, (2) shallow sites with relatively high nutrient values characterised by Fragilaria species, and (3) more acid and dilute sites with high amounts of snow cover in the catchments characterised by small Achnanthes species and Navicula digitulus. Five sediment cores representing the recent past were also analysed for diatoms. Three shallow sites were dominated by Fragilaria species throughout the period represented by the cores and no shifts in inferred pH were found. At two deeper sites (Arresjøen, Birgervatnet) major assemblage shifts are found which are unrelated to independent evidence for atmospheric contamination. Early (ca. 1200 AD) changes found at both sites are possibly related to the onset of the 'Little Ice Age'. Later changes are neither synchronous nor similar in nature and might be best explained as individual responses to the recovery from the 'Little Ice Age' and subsequent climatic warming.

Distribution and Autecology of Chrysophyte Cysts from High Arctic Svalbard Lakes: Preliminary Evidence of Recent Environmental Change

“…This is similar to Jones and Birks (2004) who report that ca. 15% of the diatom flora in 23 lakes could not be assigned to described forms.…”

“…The first group, including the two left quadrants of the ordination, includes lakes A, B, D, O, Q, and S (Figure 2). This group is similar to Jones and Birks (2004) diatom TWINSPAN group 2, characterised by shallow, strandflat lakes dominated by Fragilaria species. Lakes in cyst group 1 are relatively shallow, calcium-rich, high conductivity, relatively high dissolved TP, and predominantly high pH sites located on carbonate bedrock.…”

“…However, many chrysophytes are spring-blooming and would be sensitive to this sudden drop in pH. Interestingly, Jones and Birks (2004) find no changes in lake-water pH inferred from the diatom assemblages from five sites on Svalbard but these sites were not examined for chrysophyte cysts or cysts were not present in sufficient quantities in the 'bottom' sediments at lakes Q and S (Birks et al 2004a). …”

“…The second cyst group is similar to diatom group 3 of Jones and Birks (2004), and forms a much less cohesive cluster on the right side of the ordination (Figure 2), and consists of lakes located on granite bedrock (G, H, I, K, M, N). These lakes are generally acidic and oligotrophic, with low conductivity and ionic concentrations.…”

Recent Environmental Change and Atmospheric Contamination on Svalbard as Recorded in Lake Sediments – Modern Limnology, Vegetation, and Pollen Deposition

“…Details of the other analytical techniques used in this study are given in the subsequent papers of this special issue (Appleby 2004;Betts-Piper et al 2004;Boyle et al 2004;Brooks and Birks 2004;Jones and Birks 2004;Rose et al 2004). …”