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    Efficiency of plasma-processed air for biological decontamination of crop seeds on the premise of unimpaired seed germination
    (Hoboken, NJ : Wiley Interscience, 2021) Wannicke, Nicola; Wagner, Robert; Stachowiak, Joerg; Nishime, Thalita M.C.; Ehlbeck, Joerg; Weltmann, Klaus‐Dieter; Brust, Henrike
    In this study, the antimicrobial effect of plasma-processed air (PPA) generated by a microwave-induced nonthermal plasma was investigated for preharvest utilization using three crop species: Barley, rape, and lupine. Bacillus atrophaeus spores were chosen as a model, inoculated onto seeds, and subsequently treated with PPA at two different flow rates, different filling regimes, and gas exposure times. PPA treatment was efficient in reducing viable spores of B. atrophaeus, reaching sporicidal effects in all species at certain parameter combinations. Maximum germination of seeds was strongly reduced in barley and rape seeds at some parameter combination, whereas it had a modest effect on lupine seeds. Seed hydrophilicity was not altered. Overall, PPA investigated in this study proved suitable for preharvest applications.
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    Origin and fate of dissolved organic matter in four shallow Baltic Sea estuaries
    (Dordrecht [u.a.] : Springer Science + Business Media B.V., 2020) Voss, Maren; Asmala, Eero; Bartl, Ines; Carstensen, Jacob; Conley, Daniel J.; Dippner, Joachim W.; Humborg, Christoph; Lukkari, Kaarina; Petkuviene, Jolita; Reader, Heather; Stedmon, Colin; Vybernaite-Lubiene, Irma; Wannicke, Nicola; Zilius, Mindaugas
    Coastal waters have strong gradients in dissolved organic matter (DOM) quantity and characteristics, originating from terrestrial inputs and autochthonous production. Enclosed seas with high freshwater input therefore experience high DOM concentrations and gradients from freshwater sources to more saline waters. The brackish Baltic Sea experiences such salinity gradients from east to west and from river mouths to the open sea. Furthermore, the catchment areas of the Baltic Sea are very diverse and vary from sparsely populated northern areas to densely populated southern zones. Coastal systems vary from enclosed or open bays, estuaries, fjords, archipelagos and lagoons where the residence time of DOM at these sites varies and may control the extent to which organic matter is biologically, chemically or physically modified or simply diluted with transport off-shore. Data of DOM with simultaneous measurements of dissolved organic (DO) nitrogen (N), carbon (C) and phosphorus (P) across a range of contrasting coastal systems are scarce. Here we present data from the Roskilde Fjord, Vistula and Öre estuaries and Curonian Lagoon; four coastal systems with large differences in salinity, nutrient concentrations, freshwater inflow and catchment characteristics. The C:N:P ratios of DOM of our data, despite high variability, show site specific significant differences resulting largely from differences residence time. Microbial processes seemed to have minor effects, and only in spring did uptake of DON in the Vistula and Öre estuaries take place and not at the other sites or seasons. Resuspension from sediments impacts bottom waters and the entire shallow water column in the Curonian Lagoon. Finally, our data combined with published data show that land use in the catchments seems to impact the DOC:DON and DOC:DOP ratios of the tributaries most. © 2020, The Author(s).