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Leujak, Wera

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Wera
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  • Veröffentlichung
    Eutrophication, contaminants, litter and climate change
    (2022) Busse, Lilian; Claussen, Ulrich; Krakau, Manuela; Künitzer, Anita; Leujak, Wera; Weiß, Andrea; Werner, Stefanie
    Die Ostsee ist nach wie vor von zahlreichen Belastungen betroffen. Es sind weitere Anstrengungen erforderlich, um diese zu reduzieren und gesunde und widerstandsfähige Meeresökosysteme sowie ihre nachhaltige Nutzung zu erreichen. Dies kann nur durch die Zusammenarbeit der Ostseeanrainerstaaten und eine starke regionale Governance erzielt werden. Der Ostseeaktionsplan ist das vielversprechendste Instrument, diese Bemühungen für die Ostsee umzusetzen und die globalen Ziele des Meeresschutzes voranzubringen. ©2022 Walter de Gruyter GmbH
  • Veröffentlichung
    Eutrophication assessment in the transit area German Bight (North Sea) 2006-2014 - Stagnation and limitations
    (2018) Brockmann, Uwe; Topcu, Dilek H.; Leujak, Wera; Schütt, M.
    The eutrophication status of the German Bight (North Sea) has been assessed the third time since 1998 according to the OSPAR-Comprehensive Procedure between 2006 and 2014. Since the 1980s nutrient discharges and atmospheric nitrogen deposition had declined significantly but chlorophyll a and nutrient concentrations remained above assessment levels inshore and in inner coastal waters, reflecting continuing eutrophication. Recently local river discharges stagnated or increased again and total nitrogen remained above a reduction target of 200 myM. Most nutrients and conversion products were imported by a coastal current, passing the German Bight. Organic matter was trapped in offshore bottom waters in the ancient Elbe valley, causing repeated annual oxygen minima (<6 mg/L) and a classification as Problem Area. Effects of national reduction measures are limited in the transit area German Bight because improvements in open coastal waters require international efforts, based on comprehensive analyses. © 2018 Elsevier Ltd. All rights reserved.
  • Veröffentlichung
    Nutrient criteria for surface waters under the European Water Framework Directive: Current state-of-the-art, challenges and future outlook
    (2019) Poikane, Sandra; Claussen, Ulrich; Kelly, Martyn G.; Salas Herrero, Fuensanta; Leujak, Wera
    The aim of European water policy is to achieve good ecological status in all rivers, lakes, coastal and transitional waters by 2027. Currently, more than half of water bodies are in a degraded condition and nutrient enrichment is one of the main culprits. Therefore, there is a pressing need to establish reliable and comparable nutrient criteria that are consistent with good ecological status. This paper highlights the wide range of nutrient criteria currently in use by Member States of the European Union to support good ecological status and goes on to suggest that inappropriate criteria may be hindering the achievement of good status. Along with a comprehensive overview of nutrient criteria, we provide a critical analysis of the threshold concentrations and approaches by which these are set. We identify four essential issues: (1) Different nutrients (nitrogen and/or phosphorus) are used for different water categories in different countries. (2) The use of different nutrient fractions (total, dissolved inorganic) and statistical summary metrics (e.g., mean, percentiles, seasonal, annual) currently hampers comparability between countries, particularly for rivers, transitional and coastal waters. (3) Wide ranges in nutrient threshold values within shared water body types, in some cases showing more than a 10-fold difference in concentrations. (4) Different approaches used to set threshold nutrient concentrations to define the boundary between "good" and "moderate" ecological status. Expert judgement-based methods resulted in significantly higher (less stringent) good-moderate threshold values compared with data-driven approaches, highlighting the importance of consistent and rigorous approaches to criteria setting. We suggest that further development of nutrient criteria should be based on relationships between ecological status and nutrient concentrations, taking into account the need for comparability between different water categories, water body types within these categories, and countries. © 2019 The Authors. Published by Elsevier B.V.
  • Veröffentlichung
    Daten zur Umwelt 2018: Umwelt und Landwirtschaft
    (2018) Baumgarten, Corinna; Bilharz, Michael; Döring, Ulrike; Eisold, Andreas; Friedrich, Barbara; Frische, Tobias; Gather, Corinna; Günther, Dirk; Große Wichtrup, Walburga; Hofmeier, Katja; Hofmeier, Maximilian; Jering, Almut; Klatt, Anne; Köder, Lea; Lamfried, Daniel; Langner, Marcel; Leujak, Wera; Marx, Marc; Matthey, Astrid; Mohaupt, Volker; Osiek, Dirk; Penn-Bressel, Gertrude; Plambeck, Nils Ole; Pohl, Marian; Rechenberg, Jörg; Scheuschner, Thomas; Deutschland. Umweltbundesamt
    Diente die Landwirtschaft früher vor allem dazu, die Menschen im eigenen Land mit Nahrung zu versorgen, ist sie heute Teil weltweiter Handelsströme – vom Import von Futtermitteln bis zum Export von Fleisch in alle Welt. Diese moderne Landwirtschaft produziert große Mengen günstiger Nahrungsmittel, bleibt aber nicht ohne Folgen für die Umwelt. Die vorliegende Broschüre liefert eine Fülle von Zahlen, Daten und Fakten – Grundlage für die Diskussion und um Wege in eine nachhaltigere und umweltschonendere Landwirtschaft zu finden.>> Sollten Sie beim Download der PDF-Datei Probleme haben, versuchen Sie es bitte mit einem anderen Internetbrowser. <<