Coastal wetlands can serve as natural laboratories for assessing the future impacts of sea-level rise and the intricacies of the effect of sulfate (SO42-) on emissions of greenhouse gases, such as methane (CH4) and carbon dioxide. In the case of previously drained and freshened wetlands, we can observe how freshwater terrestrial microbial communities react and adapt to intrusion of SO42- rich saline waters. We conducted a 3-month anoxic incubation experiment with soil extracted from a peatland on the German Baltic coast which was rewetted with brackish water in late 2019 to examine how microbial communities at the site had adapted to the new conditions after two years. Soil slurries were incubated at a moderate temperature of 15 °C at two different salinities (reflecting surface water and average peat soil water salinity) and sampled at 8 timepoints. At each timepoint 5 replicates of each treatment were destructively harvested and sampled for concentrations of CH4, dissolved inorganic carbon (DIC), total aqueous organic carbon, SO42-, ammonium, and other major ions, pH values, qPCR analysis, and δ13DIC and δ13CH4 values.
We present a compilation and analysis of 1099 Holocene relative shore-level (RSL) indicators including 867 relative sea-level data points and 232 data points from the Ancylus Lake and the following transitional phase from 10.7 to 8.5 ka BP located around the Baltic Sea. The spatial distribution covers the Baltic Sea and near-coastal areas fairly well, but some gaps remain mainly in Sweden. RSL data follow the standardized HOLSEA format and, thus, are ready for spatially comprehensive applications in, e.g., glacial isostatic adjustment (GIA) modelling.
Sampling method
The data set is a compilation of rather different samples from geological, geomorphological and archaeological studies. Most of the data was already published in different formats. In this compilation we homogenized the meta information of the available information according to the HOLSEA database format, https://www.holsea.org/archive-your-data, which is a modification of the recommendations given in Hijma et al. (2015).
In addition to the reformatting, the majority of samples with radiocarbon dating were recalibrated with oxcal-software using the calib13 and marine13 curves. Furthermore, all sample descriptions were critically checked for consistency in positioning, levelling and indicative meaning by experts of the respective geographic region see Supplement 2.
Analytical method
In principle, it is a compilation, recalibration and revision of already published data.
Data Processing
Data of individual compilations were revised and imported into a relational database system. Therein, the data was transferred into the HOLSEA format by specified rules. By this procedure, a homogeneous categorisation was achieved without losing the original data. Also this is stored in the relational database system allowing for later updates of the transfer procedure or a recalibration of the data.
Description of data table HOLSEA-baltic-yymmdd.xlsx
The workbook in excel format contains 5 sheets, see https://www.holsea.org/archive-your-data:
· Long-form, containing the complete information available for each sample
· Short-form, a subset of attributes of the Long-form sheet
· Radiocarbon, containing the radiocarbon dating information of the respective samples
· U-series, a corresponding table containing the respective information of Uranium dating
· References, a complete reference list of the primary publications in which the individual data sampling is described.
All online sources for the compilation are included in the metadata. A full list of source references is provided in the data description file.