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Koschorreck, Jan

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  • Veröffentlichung
    Decreasing ð13C and ð15N values in four coastal species at different trophic levels indicate a fundamental food-web shift in the southern North and Baltic Seas between 1988 and 2016
    (2018) Corman, Anna-Marie; Schwemmer, Philipp; Koschorreck, Jan; Mercker, Moritz
    Marine ecosystems are exposed to increasing human pressures and climatic change worldwide. It has therefore become essential to describe ecosystem statuses with respect to multinational protection schemes, often necessitating long-term monitoring programmes. Changes in the food-web structure, which can be monitored via stable isotope measurements, represent an important descriptor of the status of marine ecosystems. We investigated long-term changes (29 years) in isotopic values (ð 13C and ð 15N) in four indicative organisms at different trophic levels in the southern North and Baltic Seas: bladderwrack (Fucus vesiculosus), blue mussel (Mytilus ssp.), eelpout (Zoarces viviparus), and herring gull (Larus argentatus). Time series analyses using generalised additive models revealed largely consistent declines in ð 13C and ð 15N throughout all trophic levels of the coastal food web at all study sites, indicating a clear change in these coastal regions from 1988 to 2016. There were no clear long-term patterns in egg biometrics for herring gulls, except for a consistent increase in eggshell thickness. The declines in stable isotope values were in line with the results of previous long-term studies of single higher-trophic-level species, which suggested that the noted changes were mainly caused by altered foraging patterns of the studied species. The current results demonstrate that declines in ð 13C and ð 15N have occurred throughout the whole food web, not just in particular species. We discuss the possible reasons for the decrease in stable isotope values, including decreasing eutrophication and an increase in terrestrial carbon sources. © Springer International Publishing AG, part of Springer Nature 2018
  • Veröffentlichung
    Assessment of seafood contamination under the marine strategy framework directive: contributions of the German environmental specimen bank
    (2018) Fliedner, Annette; Rüdel, Heinz; Knopf, Burkhard; Koschorreck, Jan
    Descriptor 9 (D9) of the European Union Marine Strategy Framework Directive refers to the compliance of contaminant levels in fish and other seafood of a defined marine region or subregion with human health threshold values. This requires georeferenced samples that are often difficult to obtain when relying on commercial fisheries or programs designed for monitoring human exposure. The present study examines whether georeferenced samples of blue mussel (Mytilus edulis) and eelpout (Zoarces viviparus) fillet of the German environmental specimen bank (ESB) can be used in this context. The suitability of the ESB samples, procedures, and analytical methods is evaluated with respect to D9 requirements. Based on ESB data for the D9 relevant contaminants Pb, Cd, Hg, â Ì4 PAHs, PCDD/Fs, dioxin-like (dl)-PCBs, and indicator non-dl-PCBs and the potentially relevant substances TBT, PFOS, PBDE, and HBCDD, the Good Environmental Status for D9 is assessed at the ESB sites in the North and Baltic Seas. The overall evaluation indicates that ESB samples are suitable for D9 assessment with the limitation that only coastal areas of the North and Baltic Seas are covered. Over a period of up to 30 years, concentrations of the D9 relevant contaminants were well below the maximum levels allowed for human consumption. © The Author(s) 2018
  • Veröffentlichung
    Chemicals of emerging concern in marine specimens of the German Environmental Specimen Bank
    (2020) Fliedner, Annette; Rüdel, Heinz; Dreyer, Annekatrin; Koschorreck, Jan
    Background Descriptor 8 of the Marine Strategy Framework Directive (MSFD) (Directive 2008/56/EC) addresses the good environmental status with regard to pollution of marine waters by chemical contaminants. Commission decision (EU) 2017/848 lays down the criteria and methodological standards on good environmental status of marine waters. Member States, in regional or subregional cooperation, shall establish lists of relevant contaminants beside those already covered by the Water Framework Directive (WFD). To provide information on emerging contaminants in marine biota, the German Environmental Specimen Bank (ESB) has compiled data of blue mussels and eelpouts from coastal sites in the North and Baltic Seas. Substances identified by the International Council for the Exploration of the Sea (ICES) as of emerging concern for the marine environment have been used as a starting point. Results and conclusions The study presents data of 19 emerging flame retardants and degradation products, 40 per- and polyfluoroalkyl substances (PFAS) and three cyclic volatile methylsiloxanes (cVMS). Among the emerging flame retardants, only Dec 602 was detected in all samples of 2015. Dec 604, Cl10-antiDP, 1,5-DPMA, EH-TBB, PBEB, TBP-AE, BATE, BTBPE and HBBz were constantly <†limit of quantification (LOQ). Time trends were barely detected. Legacy PBDE still dominates in most samples. PFAS concentrations were usually higher in samples from the North Sea sites compared to samples from the Baltic Sea. PFOS dominated in most samples. Increasing trends over time were detected for PFNA, PFDA and PFDoDA at the Baltic Sea site and for PFDA at one North Sea site. Concentrations of the cVMS D4, D5 and D6 were below the detection limit at the ESB sampling sites. Based on the results, it should be considered to include the emerging flame retardants DP and Dec 602 and the long-chain perfluoroalkyl substances PFNA, PFDA, PFUnDA and PFDoDA in a regular monitoring in the North and Baltic Seas. © The Author(s) 2020