ALBERT

Beschreibung: Seagrass meadows, one of the world's most important and productive coastal habitats, are threatened by a range of anthropogenic actions. Burial of seagrass plants due to coastal activities is one important anthropogenic pressure leading to the decline of local populations. In our study, we assessed the response of eelgrass Zostera marina to sediment burial from physiological, morphological, and population parameters. In a full factorial field experiment, burial level (5-20cm) and burial duration (4-16 weeks) were manipulated. Negative effects were visible even at the lowest burial level (5 cm) and shortest duration (4 weeks), with increasing effects over time and burial level. Buried seagrasses showed higher shoot mortality, delayed growth and flowering and lower carbohydrate storage. The observed effects will likely have an impact on next year's survival of buried plants. Our results have implications for the management of this important coastal plant.

Beschreibung: The coastal areas of the Baltic Sea represent highly variable environments. In order to record the environmental conditions in shallow water habitats of the SW Baltic Sea, a monitoring program was established. The monitoring sites are located along the Baltic Sea coast of Schleswig-Holstein, Germany. Thirteen stations were established, with samplings for dissolved inorganic nutrient concentrations at all stations and continuous recordings of environmental parameters (temperature, salinity, dissolved oxygen) at nine stations, respectively. Twice per month water samples were collected from a water depth of 1 m at all stations. The samples were analyzed for the concentration of dissolved inorganic nutrients (total oxidized nitrogen, nitrite, ammonia, phosphate and silicate) by UV/VIS spectroscopy using a Continuous Flow Analyzer (San++ Automated Wet Chemistry Analyzer, Skalar Analytical B.V.). For continuous recordings of temperature, salinity and dissolved oxygen concentrations, self-contained data loggers were deployed at 2.5 m depth. Two types of data loggers were used in this study: (I) MiniDOT loggers (Precision Measurement Engineering; http://pme.com; ±10 µmol L-1 or ±5 % saturation) including antifouling copper option (copper plate and mesh) to measure dissolved oxygen concentration and (II) DST CT salinity & temperature loggers (Star-Oddi; http://star-oddi.com; ±1.5 mS cm-1) recorded the conductivity. Both sensors additionally recorded water temperature with an accuracy of ± 0.1 °C. The sampling interval was set to 10 minutes for all parameters. The data for dissolved oxygen concentration was corrected for a depth of 2.5 m using the software provided by the manufacturer. Additionally, a manual compensation for salinity was calculated (see details in related article). Quality control was carried out by implementing spike and gradient tests, following recommendations of SeaDataNet quality control procedures (see https://seadatanet.org/Standards/Data-Quality-Control). All data values were flagged according to applied quality checks using the following flags: 1 = Pass, 2 = Suspect, 3 = Fail, 4 = Visually suspect, 5 = Salinity compensation fail (further explanations can be found in related article). Please note that for station 6 no data for temperature, salinity and dissolved oxygen concentration are available, since the complete logger station failed.

Beschreibung: Three study regions along the shallow waters of the southwestern Baltic Sea coastline were selected for a sampling of hard-bottom communities. Within each study region, three boulder fields (=sampling stations) were chosen. At each sampling station, samples were taken by SCUBA divers at 5 m water depth by scraping off the attached biota within a 10 x 10 cm sampling frame. In addition, the length, width and height of each sampled boulder were measured. As a result of the used sampling frame, the smallest boulder that was sampled had a diameter of ≈ 15 cm. In case the diameter of a boulder exceeded 30 cm, sampling was repeated along the longest axis of the boulder with 30 cm separating neighboring sampling frames. The collected material was fixed in a buffered formaldehyde solution (final concentration of 4%) and identified to the lowest taxonomic level possible. Accordingly, the species richness and the presence/absence of benthic species was recorded for each boulder. Since larger boulders contained several samples, species lists for areas of single frames were cumulated to obtain the total species inventory of the respective boulder. In addition, the functional diversity of the communities is given. All recorded species were categorized based on adult body size, growth form, trophic type and motility (see related article for further information). Consequently, each species was assigned to a functional group (four letters code) by the combination of its functional traits.