Description: Nodularia spumigena is a toxic, filamentous cyanobacterium capable to fix atmospheric nitrogen, which is often dominating cyanobacterial bloom events in the Baltic Sea and other aquatic systems worldwide. Phosphate (P) limitation has been considered as one environmental parameter that is somehow promoting the establishment of cyanobacterial mass developments. In the present study, we analyzed the response of Nodularia spumigena strain CCY9914 towards strong phosphorus limitation in an experimental approach. Pre-experimental and experimental incubations were performed at the Department of Plant Physiology (University of Rostock, Germany). Specifically, cultures were incubated under P-replete and P-deplete conditions for 21 days. The P-replete medium was composed as follows: 33% ASNIII and 67% BG11 medium mixture (as described by Hagemann et al., 2019), with 0.02 g L-1 K2HPO4 in the modified ASNIII (Rippka et al., 1979) and 0.00078 mg L-1 K2HPO4 in BG11 medium modified with 20 mM TES buffer to pH 8 (Rippka et al., 1979). Conversely, the P-deplete medium did not contain any additional P. Samples were collected after 3 hours (day 0), 7, 14 and 21 days from the start of the experiment to assess the variation of the following physiological parameters: biomass increase estimated by dry weight measurements and polyphosphate accumulation measured according to Martin et al. (2014). Additionally, ortho-phosphate and ammonium concentrations were measured in the medium to assess nutrient conditions during the course of the experiment. The experiment was repeated two times. During the second iteration of the experiment, samples from d7 and d14 were used for differential gene expression analysis (RNA-seq data available on Gene Expression Omnibus (GEO) accession GSE213384).

Description: This dataset comprises environmental parameters for biological soil crusts in coastal sand dunes in northern Germany. Biological soil crusts (biocrusts) are autonomous ecosystems consisting of prokaryotic and eukaryotic microorganisms growing on the topsoil. They colonize global climatic zones, including temperate dunes. This study examined changes in the community structure of biocrust phototrophic organisms along a dune chronosequence at the Baltic Sea compared to an inland dune in Northern Germany. The community composition and their shift between different successional stages of dune development were related to physico-chemical sediment properties. A vegetation survey followed by species determination and sediment analyses were conducted. The sampling took place on the 25th of April and on the 5th of May 2020. The samples were collected at a costal dune area, namely the Schaabe spit on the island Rügen, Mecklenburg Wester-Pomerania, Germany, and in an inland dune area at Verden (Aller), Lower Saxony, Germany. Biocrust samples were taken along one transect per study site. Each transect followed a natural succession gradient in the dune area. Along each transect, the different successional dune stages were visually identified and further named as dune subsites. At each subsite, a sampling plot of 1 m2 was established and used for further vegetation analyses, biocrust and sediment sampling. Along the Schaabe spit transect four subsites with one sampling plot each were established and three subsites were established in the inland dune in Verden. For the vegetation survey seven different functional groups were defined describing the overall surface coverage: Thin (1-3 mm) green algae-dominated biocrusts were defined as early successional stages. Later successional stages, in which the green algae biocrusts became slightly thicker (3-8 mm) and moss-covered, were defined as the intermediate successional biocrust stage. Moss-dominated biocrusts and those who additionally lichenized characterized the mature successional stages of biocrusts. Vascular plants, and litter (dead material, i.e., pine needles, leaves, and branches) were two of the non-cryptogamic but still biotic functional groups. Bare sediment was the only abiotic functional group. The predefined functional groups were recorded within each plot according to the point intercept method by Levy and Madden (1933). Each of the seven sampling plots was divided into 16 equal subplots (0.0625 m2). A 25 cm x 25 cm (0.0625 m2) grid of 25 intersections was placed randomly into 4 of these subplots. Within each sub-plot, the functional groups were recorded by 25 point measurements according to the approach of Williams et al. (2017). That allowed 100 point measurements per sampling plot (1 m2).