Catherine Zucco, Wolfgang Wende, Thomas Merck, Irene Köchling and Johann Köppel (eds.) Ecological Research on Offshore Wind Farms: International Exchange of Experiences PART B: Literature Review of Ecological Impacts BfN-Skripten 186 2006 Ecological Research on Offshore Wind Farms: International Exchange of Experiences (Project No.: 804 46 001) PART B: Literature Review of the Ecological Impacts of Offshore Wind Farms Editors: Catherine Zucco Wolfgang Wende Thomas Merck Irene Köchling Johann Köppel Cover Pictures (clockwise): Sea gull, research platform, benthic community (Krause & Hübner, BfN); Common Seal (Wollny-Goerke, Hamburg); windfarm Rønland (Steinhauer, TU Berlin); windfarm Nysted (background) (Krause & Hübner, BfN) Editors´ addresses: C. Zucco, T. Merck, I. Köchling Bundesamt für Naturschutz Federal Agency for Nature Conservation Außenstelle Vilm 18581 Putbus W. Wende, J. 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Bonn, Germany 2006 I TABLE OF CONTENTS 1 Literature Review of Offshore Wind Farms with Regard 1 to Benthic Communities and Habitats Karin Meißner & Holmer Sordyl 2 Literature Review of Offshore Wind Farms with Regard 47 to Fish Fauna Oliver Keller, Karin Lüdemann & Rudolf Kafemann 3 Literature Review of Offshore Wind Farms with Regard 131 to Seabirds Volker Dierschke & Stefan Garthe 4 Literature Review of Offshore Wind Farms with Regard 199 to Marine Mammals Klaus Lucke, Sandra Storch, Justin Cooke & Ursula Siebert Funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety through the Federal Agency for Nature Conservation II MEIßNER & SORDYL: Offshore Wind Farms and Benthic Communities and Habitats 1 Literature Review of Offshore Wind Farms with Regard to Benthic Communities and Habitats Karin Meißner & Holmer Sordyl Institut für Angewandte Ökologie Forschungsgesellschaft mbH Alte Dorfstraße 11 18184 Neu Broderstorf, Germany [email protected] Contents 1 Summary ................................................................................................................. 2 2 Zusammenfassung ................................................................................................. 3 3 Background and Objectives .................................................................................. 6 4 Sources of Information........................................................................................... 7 4.1 Experience and Data from Offshore Wind Farm Developments ................7 4.2 Practical Approaches.....................................................................................8 4.3 Theoretical Approaches.................................................................................8 5 State of Knowledge................................................................................................. 9 5.1 Noise and Vibration........................................................................................9 5.2 Temperature..................................................................................................10 5.3 Electromagnetic Fields ................................................................................14 5.4 Disturbance...................................................................................................17 5.4.1 Changes in Biotope Characteristics ................................................17 5.4.1.1 Current and Wave Regime .....................................................17 5.4.1.2 Disturbance of the Seabed .....................................................18 Direct Habitat Loss.................................................................. 18 Scour ..................................................................................... 18 Contamination ........................................................................ 20 5.4.1.3 Habitat Destruction.................................................................21 5.4.2 Physical Disturbance and Damage to Benthic Organisms ............22 5.4.3 Introduction of New Faunal Components and “Reef Effects” .......26 6 Conclusions and Recommendations.................................................................. 30 6.1 Effect Monitoring..........................................................................................31 6.1.1 Existing Concepts……………… ........................................................31 6.1.2 Proposal for a Monitoring Concept for the Operational Phase of Offshore Wind Farms in the German EEZ ...................................34 7 References ............................................................................................................ 39 1 2 MEIßNER & SORDYL: Offshore Wind Farms and Benthic Communities and Habitats 1 Summary A literature review of ecological research on offshore wind farms with regard to benthic habitats and communities is presented in this article. Information was gathered from reports compiled in the course of wind farm developments, research project reports (practical and theoretical approaches), and the scientific literature. Noise and vibration, heat emission, electromagnetic fields and disturbance have been identified as potential impact sources. Available information related to the different impact sources are reviewed in separate chapters. A summary of contents is given below. NOISE AND VIBRATION Various source levels of offshore wind farm related noise are available. Studies linking both noise and marine wildlife observations are scarce. Response to noise could be observed under experimental conditions. Under field conditions, avoidance might be the most common response to underwater noise. Colonization of wind turbines is taken as an indication that noise and vibration do not have detrimental effects on the attached fauna. Further studies are required to significantly add knowledge about the effects of noise and vibration on marine invertebrates. TEMPERATURE Temperature rise in the sediment is predicted based on different theoretical models. Results of such calculations are cited. Most studies predict the sediment temperature rise not to exceed 2 K at 20 cm sediment depth if the cable burial depth is 1 m. Models also predict much higher sediment temperatures in close vicinity to the cables. Heat emission is discussed in the context of changes in the physico-chemical conditions of sedimentary substrates, which could cause changes in the distribution of species. In the scientific literature, the change of benthic community composition is mainly discussed in connection with thermal discharges from power plants. Also, an assessment of likely effects of seawater warming for particular species is presented. ELECTROMAGNETIC FIELDS The cccurrence of electric and magnetic fields dependent on power cable type is explained. Data available on both anticipated and measured field strength are reviewed. In conclusion, none of the studies performed to date to assess the impact of undersea cables on migratory fish (e.g. salmon and eels) and all the relatively immobile fauna inhabiting the sea floor (e.g. molluscs), has found any substantial behavioural or biological impact. In regard to benthic marine invertebrates, such effects may only occur in close vicinity to the cables. DISTURBANCE Disturbance has been identified as one of the major impact factors in the course of offshore wind farm development. The term “disturbance” includes a number of different impact factors. It is necessary to distinguish between indirect and direct effects. Indirect effects primarily affect the marine environment, and thus secondarily affect the benthic community. Direct effects on organisms include physical disturbance, damage, displacement and removal. Effects on the marine environment include all changes in biotope characteristics. Such changes discussed include changes of current and wave regime, disturbance of the seabed, and habitat destruction. None of these changes is reported to affect the marine environment on a large scale. MEIßNER & SORDYL: Offshore Wind Farms and Benthic Communities and Habitats 3 Physical disturbance and damage to benthic organisms is widely discussed in the scientific literature. Contradictory results are presented regarding the effects on benthic communities due to disturbance, but based on the results of the majority of studies, changes in zoobenthic species composition, abundance or biomass are very likely