Climate change is one of the major threats to life on earth and a rapid transition from fossil fuels to more sustainable, renewable energy sources is universally recognized by the global scientific community as an unavoidable priority. Offshore wind is developing at a very high speed and is seen as a major contributor to the solution of the demand for clean energy. This is particularly true for the North Sea, but also elsewhere in the world. However, any large-scale implementation of infrastructure will have some impact on the ecosystem. Potentially harmful effects of wind farms, such as interference with migration routes, as well as loss of feeding habitat for seabirds, collisions with bats and damaging effects of noise from pile driving on fish and marine mammals are receiving a great deal of attention. On the other hand, offshore wind farms generally constitute exclusion areas for intensive fishing and can also seen as opportunities for restoring lost keystone species and ecosystem functions. New marine habitats created by turbine foundations and the surrounding scour protection are rapidly colonized by hard-substrate organisms. These organisms constitute an additional food source for higher trophic levels and influence the surrounding sediments. However, larger-scale consequences of such artificial reef effects on higher trophic levels are not yet clear. Recently, it has emerged that the introduction of turbines may also influence local hydrodynamics, SPM-dynamics and therefore also fundamental ecological processes, such as primary production – the basis of the marine food web. At present, certain effects (e.g. impacts on stratification) have been measured within and in the immediate vicinity of some existing offshore wind farms. However, the first results of (hypothetical) future wind farm scenarios using numerical models, indicate that impacting such physical processes may in the future have far reaching effects throughout the marine food web. While some processes are well understood and can be modelled with a certain amount of confidence, the knock-on effects of shifts at the base of the food web on fish and other higher trophic levels are largely unknown. Guidelines and policy objectives generally target these higher trophic levels. Hence, there are significant gaps between ecological assessment frameworks for offshore wind regarding these ecosystem effects that act through the marine food web. Lagging behind the offshore wind industry, but rapidly catching up, are the developments around offshore solar energy, tidal energy, wave energy and other forms of marine energy generation. These technologies, when implemented at a large scale, will also interact with the system in cumulation with the effects of offshore wind. This session invites contributions focusing on understanding and assessing the magnitude of ecosystem effects, negative as well as positive, due to marine energy infrastructure.
Lead Organizer: Luca van Duren, Deltares (luca.vanduren@deltares.nl)
Co-organizers:
Lauriane Vilmin, Deltares (lauriane.vilmin@deltares.nl)
Jan Vanaverbeke, Royal Belgian Institute of Natural Sciences (jvanaverbeke@naturalsciences.be)
Josep Lloret, Universitat de Girona (Josep.lloret@udg.edu)
Presentations
05:00 PM
Underwater ecosystem effects of energy farms: what to expect? (5082)
Tutorial/Invited: Invited, Tutorial
Primary Presenter: Peter Herman, Deltares (peter.herman@deltares.nl)
The large-scale implementation of offshore energy harvesting in shallow coastal seas will likely have ecological consequences. Much attention has been paid to impacts of windmills on birds, but underwater effects of windfarms and offshore solar have received less attention. We summarize known or expected effects in this contribution, and discuss possibilities for mitigating effects. Windfarms extract energy from the wind and consequently modify the air-water interaction. In addition, energy is extracted from the tidal motion of the water and dissipated as turbulence. Both interactions change vertical mixing of the water column, affecting the distribution of dissolved and particulate matter. It is expected that, at least locally, this will lead to changes in primary production. Changes in bottom shear stress lead to altered suspended matter dynamics. Offshore solar primarily affects light climate, but may also interferes with physical effects of windfarms. Energy farms change the physical habitat characteristics of shallow seas, by introducing hard substrate in a soft-sediment environment. The transport of energy as electric current or, in the future, as hydrogen, may entail further habitat modifications. Large energy hubs and extensive cable and pipeline networks extend the physical impacts to sensitive coastal areas. This will change faunal communities and affect the balance between pelagic and benthic grazers. Indirectly, these changes may affect the food web in the sea and the biological factors responsible for pelagic-benthic exchange of mineral and organic matter.
05:15 PM
Is offshore wind energy production compatible with conservation goals of Natura 2000 sites and other marine protected areas in the Mediterranean Sea? (7340)
Primary Presenter: Josep LLORET, University of Girona (josep.lloret@udg.edu)
With the goal of Europe becoming climate neutral by 2050, the European marine space allocated to wind energy will multiply by 15. At the same time, European Union member countries have obligations towards achieving Natura 2000 objectives and the Marine Strategy Framework Objective. As offshore wind energy expands in Europe, maritime planners need to increasingly consider the potential effects of these activities on Natura 2000 sites and other types of marine protected areas (MPAs). The goal of this paper is to critically review the development of offshore wind energy within Mediterranean Natura 2000 sites and other MPA types, taking as example the western Mediterranean Sea, where most of the offshore wind developments have been proposed. In order to open discussion on offshore wind energy policy in Mediterranean MPAs, and guide ecological research that supports holistic decisions of OWF implementation in the region, we (i) outline the context of Natura 2000 and other MPA policy in the Mediterranean for OWF development, (ii) summarize the potential impacts of OWF on EU-protected habitats and species, (iii) assess the interaction of OWF, Natura 2000 sites and other types of MPAs, and (iv) propose recommendations to approach OWF development in the Mediterranean to safeguard Natura 2000 sites and other MPAs. Although this study is focused in the western Mediterranean, lessons learned can be also useful for other areas of the Mediterranean and other European seas.
05:30 PM
STABLE ISOTOPE FINGERPRINTING THROUGH AMINO ACID CONTENT IN FAECAL PELLETS OF FOULING FAUNA FROM OFFSHORE WIND FARMS. (7041)
Primary Presenter: Esther Cepeda Gamella, Royal Belgium Institute of Natural Sciences (ecepedagamella@naturalsciences.be)
The North Sea is a world-leading area in Offshore Wind Farms (OWFs) energy production. The presence of OWF turbines affects the local marine ecosystem structure and its functioning. The turbines provide new artificial hard substrates, rapidly colonized by epifaunal organisms, mainly consisting of suspension-feeding communities dominated by blue mussel (Mytilus edulis), tube-building amphipods (Jassa herdmani), and plumose anemones (Metridium senile). They feed by removing suspended particate matter, zooplankton, and phytoplankton from the water column, and return faecal pellets (FP) to the water column. These FP are thought to play a crucial role in the local organic matter (OM) dynamics and carbon sequestration in the sediment surrounding the turbines. To quantify their importance within the pelagic and benthic OM pools of OWFs ecosystems, it is essential to develop tracers for FP of the dominant species and other contributors (phyto-, zooplankton, and bacteria-degraded OM). We incubated the three species of interest in controlled lab conditions to harvest species-specific FP. We then analyzed the δ15N signal of the individual AA in these FP, and the other components of the marine OM pool, to develop a Compound-Specific Stable Isotope Analysis of amino acids (CSSIA–AA) fingerprint. Through multivariate techniques, the AAs with the strongest discriminating power between the potential sources are identified. These AAs will subsequently be used in a Bayesian Mixing Model, to finally estimate the proportional contribution of FP to the OM pool of the OWF environment.
05:45 PM
Potential ecosystem effects of large-scale implementation of offshore wind in the North Sea (5918)
Primary Presenter: Lauriane Vilmin, Deltares (lauriane.vilmin@deltares.nl)
The southern North Sea is a relatively shallow shelf sea, heavily utilised by human activities. All surrounding countries are developing offshore wind farms and all countries have plans for significant upscaling in the coming decades. The introduction of thousands of turbines in the system may influence local hydrodynamics, stratification patterns, SPM-dynamics and therefore also fundamental ecological processes, such as primary production – the basis of the marine food web. Our aim is to assess which areas of the North Sea may be susceptible to fundamental changes in ecosystem functioning. With a suite of coupled state-of-the-art models, we have run scenarios without any wind farms, and scenarios with different levels of upscaling. Scenarios with significant upscaling of offshore wind indicate that there are large areas in the North Sea, where potentially significant effects may occur on the physical functioning of the system, which in turn may affect the North Sea ecosystem. Ecosystem effects differed in different areas of the North Sea, some areas are likely to see an increase in primary production, others a reduction. Changes can also be expected in the timing of the spring bloom. Within this project we are trying to understand the bottom up effects of offshore wind farms on the North Sea food web and the potential knock-on effects on higher trophic levels. This presentation shows the first steps to understand effects that are perhaps not so visible and obvious, but potentially far-reaching.
06:00 PM
Near-field measurements around offshore wind turbines show how they enhance hydrodynamics in their direct environment (5805)
Primary Presenter: Erik Hendriks, Deltares (erik.hendriks@deltares.nl)
In the southern North Sea, a relatively shallow shelf sea, offshore wind farms are being constructed and planned on an extensive scale, upscaling from 20GW in 2020 to 220 GW in 2050. The wind turbines could alter local hydrodynamics and suspended matter dynamics such that the ecosystem becomes affected. In this study, we present the results of a field campaign aiming at quantifying these changes in hydrodynamics and suspended matter dynamics, allowing the assessment of their ecological impact. The campaign was undertaken in June 2022 in the Belgian Coastal Zone. We measured a set of hydrodynamic parameters at various locations around a single turbine, supplemented with water and sediment samples. The data show how the turbine enhances the local hydrodynamics. In the turbine wake, we observed an increase in turbulent kinetic energy. This led to a more well-mixed water column. At the water surface, this resulted in colder and more saline water, while the water near the seabed became warmer and less saline. These effects were closely linked to the direction of the tidal current, as the turbine-induced wake is only several turbine diameters wide. The wake length is much longer, extending for several hundreds of meters behind the turbine. This presentation discusses the study setup and the steps required to quantify the impact of turbines on local hydrodynamics. Furthermore, we will discuss how this knowledge is implemented in large-scale models, as this step is crucial for assessing the ecosystem impact of upscaled offshore wind installations.
SS062 Ecosystem Consequences of the Energy Transition
Description
Time: 5:00 PM
Date: 5/6/2023
Room: Sala Ibiza B