Holocene diatom data from the Västervik-Gamlebyviken area, southeast coast of Sweden, Baltic Sea

Christos Katrantsiotis, Thomas Andrén, Elinor Andrén

This dataset consists of diatom species counts and total diatom concentrations from seven sediment cores taken from seven lake basins located in the Västervik-Gamlebyviken area, along the southern Baltic Sea coast in SE Sweden. The data covers the period from around 10 000  before present to the present.

The dataset was developed with the purpose to construct the Holocene shore displacement curve, interpret past sea level changes and investigate the interplay between relative sea-level changes and the development of human settlements and land-cover changes.

The sediment cores were collected in February 2017, February and March 2018 and in February 2021. Diatoms were extracted from sediments samples from different stratigraphical levels following a chemical protocol in the lab, mounted with Naphrax in slides and counted in the microscope.

Citation

Christos Katrantsiotis, Thomas Andrén, Elinor Andrén (2024) Holocene diatom data from the Västervik-Gamlebyviken area, southeast coast of Sweden, Baltic Sea. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/katrantsiotis-2024-gamlebyviken-diatoms-1

References

Katrantsiotis C, Vinogradova O, Dahl M, Palm V, Rönnby J, Gaillard M-J, Andrén T, Andrén E (2024) Holocene shoreline displacement, land-cover change and human settlement distribution at the southeast coast of Sweden. Accepted for publication in Journal of Quaternary Science.

Katrantsiotis C, Dahl M, Palm V, Rönnby J, Andrén T, Andrén E (2023) Holocene relative sea level changes in the Västervik-Gamlebyviken region on the southeast coast of Sweden, southern Baltic Sea. Boreas, 52: 206-222. https://doi.org/10.1111/bor.12605

Data description

The dataset contains diatom species data (counts) and total diatom concentrations from stratigraphical levels from seven sediment cores. The data are provided in two different formats:

1. As seven separate csv files, one for each lake. Semicolon is used as value separator.
2. As one xlsx file with seven spreadsheet tables, one for each lake.

csv files

All files have the following content, with column headers explained below:

1. depth Depth of each sample [cm below sea floor]
2. age Age [calibrated years Before Present]
3. diatom_concentration Diatom concentration [number per gram dry weight]
4. ...onwards to the last column: Counts of diatom species for each stratigraphic level. The diatom species names are provied in the column headers in the following way, for example: achnanthes_acares, achnanthes_brevipes.

The seven files are, with lake names given together with number of columns and rows:

• brannerigolen.csv Lake Brännerigölen: 230 columns, 51 rows.
• gagern.csv Lake Gagern: 174 columns, 40 rows.
• kvannaren.csv Lake Kvännaren: 114 columns, 25 rows.
• lillsjon.csv Lake Lillsjön: 172 columns, 49 rows.
• maren.csv Lake Maren: 133 columns, 31 rows.
• skarpegolen.csv Lake Skarpegölen: 171 columns, 65 rows.
• svartsjon.csv Lake Svartsjön: 150 columns, 31 rows.

xlsx file

The content in the xlsx file is presented essentially as extracted from the software Tilia, designed for managing and graphing paleontological data.

Thus, the data in the xlsx file is presented in a transposed form compared to the corresponding csv files. The columns in the xlsx file correspond to the rows in the csv files, but with the species listed in a different order.

The data in the xlsx file is also more extensive than in the csv files. Namely, the xlsx file provides the result of classification of the diatom species based on their salinity preferences and their habitat form. The group codes are briefly explained below each spreadsheet data table, in the first column.

Comments

Coring equipment

All seven lakes were cored using a 1 m long Russian peat corer with a diameter of 5 cm.

Laboratory work

In the laboratory, all the sediment cores were described for lithology and, thereafter, subsampled for proxy analyses.

Around 0.2 g of freeze-dried sediment samples at every 5⁠ – ⁠20 cm throughout the cores were prepared for diatom analysis following standard techniques (see Katrantsiotis et al. 2023). The analysis mainly focused on the section of the cores which contained the transition from the Baltic Sea stage to an isolated lake stage. Diatoms were analysed under a Leica DMLS light microscope (LM) using oil immersion and 100X magnification.

Over 400 valves were counted at each level and all species were classified based on their salinity preferences and their habitat form. See supplementary material in Katrantsiotis et al. 2023 and Katrantsiotis et al. (2024) for the classification system of the species.

Research project

SEASIDE - A multidisciplinary study of maritime environmental history.
The aim of this project is to disentangle the long-term role of human impact and natural driven processes (e.g. climate change and shoreline changes) to determine the mutual significance of the multiple stressors resulting in events of hypoxia in the Baltic Sea.

Site coordinates

• Lake Brännerigölen: 57° 44.064’ N, 16° 30.188’ E, 17.5 m a.s.l.
• Lake Gagern: 57° 48.594’ N, 16° 31.138’ E, 13 m a.s.l.
• Lake Kvännaren: 57° 44.752’ N, 16° 36.506’ E, 11.3 m a.s.l.
• Lake Lillsjön: 57° 55.934’ N, 16° 23.342’ E, 18.3 m a.s.l.
• Lake Maren: 57° 47.197’ N, 16° 34.152’ E, 2 m a.s.l.
• Lake Skarpegölen: 57° 55.128’ N, 16° 23.078’ E, 31.5 m a.s.l.
• Lake Svartsjön: 57° 47.680’ N, 16° 32.974’ E, 22 m a.s.l.