Unusual reaction of diatom assemblage on climate changes during the last millennium: a record from Spitsbergen lake

Elwira Sienkiewicz,Michał Gąsiorowski,Krzysztof Migała

doi:10.1007/s10933-017-9962-2

Elwira Sienkiewicz, Michał Gąsiorowski + Show 1 more

Open Access

https://doi.org/10.1007/s10933-017-9962-2

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Abstract

A sediment core from the Arctic Revvatnet (Hornsund area, SW Spitsbergen, Svalbard) provided data on environmental changes over the last 3100 years. Diatom analysis showing the domination of planktonic Cyclotella forms suggested good edaphic conditions until the middle of the nineteenth century, even during the Little Ice Age. A thermally stratified and relatively stable water column with good mixing allowed small, less heavily silicified Cyclotella sensu lato to develop during this time. The climate warming at the beginning of the twentieth century induced intensification of erosion processes in the catchment of the lake and caused an increase in the sedimentation rate. These processes have caused a lack of thermal stratification by disturbances in the water column and an increase of nutrients, consequently driving changes in the diatom species composition, which became dominated by benthic forms. In this period, almost all planktonic taxa disappeared or abruptly decreased in frequency. Higher temperatures accelerated the melting of nearby glaciers, which caused an increase in the activity of diatoms typical of running waters. Also a few Cladocera species appeared at the first time in the youngest samples.

Highlights

The climate changes in the last millennium have been reviewed in many papers (Jones and Mann 2004; Jones et al 2009; Wilson et al 2016)
The Arctic is changing faster than other regions of the Northern Hemisphere (Serreze and Barry 2011) and lake sediments from the Arctic areas contain a unique record of the alterations occurring in their ecosystems caused by natural and/or artificial factors
The sediment core was dated using a combination of lead-210 and radiocarbon methods according to the protocol described and tested by Hercman et al (2014)

Summary

Introduction

The climate changes in the last millennium have been reviewed in many papers (Jones and Mann 2004; Jones et al 2009; Wilson et al 2016). The major climate events of this period, namely the ‘Medieval Warm Period’ (MWP), ‘Little Ice Age’ (LIA) and modern warming, are described in relative detail in the Northern Hemisphere. The records of these episodes are not so evident in the tropics and Southern Hemisphere (Jones and Mann 2004). Specific records can exhibit local features, e.g. caused by local geology, hydrology, human activity and differ by localities in mode, timing and magnitude. The Arctic is changing faster than other regions of the Northern Hemisphere (Serreze and Barry 2011) and lake sediments from the Arctic areas contain a unique record of the alterations occurring in their ecosystems caused by natural and/or artificial factors. The adaptation to extreme living conditions by many organisms, especially aquatic phyto- and zooplankton, means that most of environmental changes were relatively quickly mirrored in community composition due to the short life cycles of these organisms

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