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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.

© The authors 2017. Intertidal areas are considered to be productive habitats, but due to the challenging and dynamic environment, in situ assessments of their performance remain scarce. Here, we aimed to quantify the production and turnover of organic material in an intertidal sediment across several consecutive diel/tidal cycles and to evaluate the importance of key drivers affecting the community performance. Time-series measurements of the oxygen (O2) microdistribution across 2 sites at a silty sandflat documented extreme variability, which was mainly driven by light availability and flow conditions. Diffusion dominated the interstitial solute transport, but advective porewater transport was observed during 15% of the 9 d study period. Photosynthetic activity never exhibited light inhibition and average daytime net photosynthesis ranged between 1.01 and 11.15 mmol m-2 d-1 depending on the daily light availability, while the assessed gross primary production was ∼80% higher. When irradiance exceeded 17.2 mol photons m-2 d-1, daytime net autotrophy more than balanced the heterotrophic activity during the night (average night-time respiration, ERn: -4.01 mmol m-2 d-1). However, despite intense primary production, the integrated activity during the target autumn period was net heterotrophic with an average net ecosystem metabolism of -2.21 (span: -7.93 to 1.48) mmol O2 m-2 d-1. This study highlights the extreme temporal and spatial variation of intertidal sediments and the importance of accounting for natural in situ dynamics to correctly assess their performance and contribution to system production.

The article focuses on the morphological development of the Wadden Sea barrier island system, with emphasis on West and East Frisian islands on several temporal and spatial scales. In addition, it integrates the insights for management purposes. Barrier island management is addressed with respect to morphology, sediment budgets, safety and natural values. We show that each of these issues is determined to some extent to various spatio-temporal scales and that the management of a barrier island has to be considered in terms of interactions on various spatial and temporal scales. Morphology of some of the barrier islands is determined by the pre-existing Pleistocene relief to a fair extent, either directly due to erosion-resistant outcrops on or near the islands, or indirectly by determining the locations where inlet systems or estuaries could develop. Where this is not the case, the larger part of the sediments are locally reworked Pleistocene or Holocene deposits eroded at the North Sea coasts of the barrier chain and deposited in the back-barrier area and on the islands as a response to sea-level rise. Hardly any sand is coming in from outside the area. In order to keep up with sea-level rise sand has thus to be nourished if coastal retreat is not allowed. During the long Holocene evolution islands and ebb-tidal deltas have been lined up during their coastward migration, forming a more or less uninterrupted barrier chain along the Frisian coasts. The present-day approach of mainly focusing on the fixation of the inhabited parts of the chain will most likely result in a de-alignment of the various parts of the chain, resulting in increasing erosion of the promontories. An inlet system is a sediment-sharing system with a tidal inlet, the ebb-tidal delta, adjacent barrier islands and the tidal basin with channels, shoals, tidal flats and salt marshes. The sand balance of a barrier island is thus directly linked to tidal inlet system development. A natural change or an intervention in the sediment-sharing system by man may thus have repercussions for the island's development. Sediment redistribution in the coastal zone may also depend on climate, as is illustrated by the rapid growth of the islands after the demise of the Little Ice Age. On the barrier islands themselves many measures were taken during the past two centuries to ensure coastal safety. The successful attempts to stabilize the coasts and dunes of the barrier islands resulted in a reduction of sand transport from and along the shoreface to the beach and onto the islands. To some extent this has been restored by applying sand nourishments. However, vertical accretion of the islands is still largely impossible due to all the older coastal protection measures still present. On the long run sedimentary dynamics are essential if the island is to accrete vertically with sea-level rise, which forms a robust and sustainable strategy to guarantee safety during the next centuries. Massive stabilization also reduced the opportunities for pioneer vegetation. Dune belts and tidal marshes have experienced a fast succession resulting in a climax vegetation and the loss of the characteristic open landscape. In order to restore nature sufficient space and time should allow natural processes to develop and to create robust ecosystems. Instead of focusing on nature conservation a paradigm shift is needed in barrier island management towards stimulating the development of natural dynamics. To our opinion the best solution is to allow the geo-biological processes to take their natural course as much as possible. Examples are given for the various parts of a prototype barrier island. Only where this is not feasible other management practices should be applied. As a rule of thumb: soft and with respect for morphodynamical integrity where possible, hard where really needed. This concept applies both to the various morpho-ecological units on the islands and to the morphological developments on larger spatio-temporal scales. © 2012 Elsevier Ltd.

Gross sedimentation rates (GSR) were measured using sediment traps placed at different levels above die seabed (0.3, 0.5, 0.8, 1.0, 2.0, 4.0, 6.0, 8.0, 10.0 m) at a water depth of 17 m. The traps were deployed for 1.25 year. The study was carried out at a location in die semi-enclosed Aarhus Bay, in the southwestern part of the Kattegat, which forms the transitional zone between the highly saline (32-34) North Sea and the less saline (15-20) Baltic Sea. Hydrographic conditions in the Aarhus Bay are dominated by significant changes in salinity during the year, and the water column was stratified for 80 % of the time. High GSR values were recorded near the seabed with a mean of 114.8 (g m-2 day-1) at 0.3 m above the seabed, whereas low GSR values were recorded in the upper traps with a mean of 5.5 (g m-2 day-1) at 10 m above the seabed. The density difference between surface and bottom water was used as a stratification parameter. A strong negative correlation between stratification and wind energy transfer was found. The negative correlation was due to opposite seasonal components of in- and outflow of waters increasing the density difference, i.e. in- and outflow occurred predominantly in seasons with calm wind conditions. Correlation coefficients were high and positive between wind energy and GSR 6.0 m above the seabed due to enhanced turbulent diffusion of suspended particulate matter in periods of strong winds. Resuspension of bottom sediments by surface waves also occurred, increasing GSR at all trap levels. A net sedimentation rate given by the Pb-210 method (2.5 g m-2 day-1) was low compared to the high GSR near the seabed (114.8 g m-2 day-1), this difference being primarily due to resuspension by currents and waves.

9 pages, The increase in exploitation and use of the aquatic environment by humans with increasing population enhances the need for knowledge for future sustainable management of lakes, coastal zones and the open ocean. A frequently used tool for process understanding and management are mathematical models that simulate global, regional and local scenarios. To be reliable models have to be calibrated and validated with high-quality field measurements. The more good data that is used the better the model becomes and forecasting possibilities