Samples were taken to study the effect of storm surges on ecosystem functioning of salt marsh microbial communities. Sediment samples were collected from experimental salt marsh islands located in the back-barrier tidal flats of Spiekeroog Island, German North Sea (53°45′N, 7°43′E). The islands consist of three elevation zones (0.7 m, 1.0 m, and 1.3 m above mean sea level), corresponding to pioneer zone, lower salt marsh, and upper salt marsh. Six islands were sampled (three initially bare; three transplanted with lower salt marsh sediment and vegetation). Sampling was conducted in September 2022 (pre-disturbance), March 2023 (post-winter storm surges), and August 2023 (recovery phase).
Surface sediments (upper 2 cm) were collected using syringe cores. Pooled samples were analyzed for chlorophyll a as a proxy for microphytobenthos biomass using ethanol extraction and spectrophotometric pigment analysis. Extracellular polymeric substances (EPS) were quantified using EDTA extraction followed by phenol–sulfuric acid carbohydrate analysis. DNA was extracted from sediment subsamples using a Qiagen PowerSoil kit. Prokaryotic abundance was estimated by quantitative PCR targeting the 16S rRNA gene (primers 519F/907R), using an Escherichia coli 16S rRNA gene standard curve. The dataset includes chlorophyll a concentrations (µg g⁻¹ dry sediment), EPS carbohydrate concentrations, and prokaryotic 16S rRNA gene copy numbers for all sampling times, elevations, and treatments.
These data are part of the measurements conducted at the time series station Boknis Eck located in the southwestern Baltic Sea at 54°31.77'N, 10°02.36'E. The data include dissolved organic carbon (DOC), total dissolved nitrogen (TDN), dissolved organic nitrogen (DON), bacterial biomes production and bacterial cell counts. Samples were taken once a month at 6 standard depths (1, 5, 10, 15, 20 and 25 m). The data was acquired onboard FK Littorina using a rosette sampler. DOC/TDN were measured using a TOC analyzer, bacterial biomass production data was acquired by leucine incorporation (70 min incubation and counted using a liquid scintillation counter), and bacterial cell abundance was determined using flow cytometry.