Search

In the early 2010s, the French government officially launched its energy transition strategy dedicated to offshore renewable energy. Since 2011, the government has launched several calls for tender for the construction of commercial fixed offshore wind farms in the English Channel and off the Atlantic coast. In parallel, in the mid-2010s, the French State showed an interest in floating wind energy, with the planning of four pilot farms off the Atlantic and the Mediterranean coasts. Although the offshore wind energy sector is growing in Europe, floating offshore wind energy deployment is currently at an early stage. Floating offshore wind energy represents a major technological breakthrough, harnessing offshore energy resources that were as yet out of reach, but which are recognized as more abundant. In addition to strengthening France's strategic positioning among the pioneer countries in Europe for the development of increasingly mature technology, floating wind turbines present other assets: diversifying the French offshore renewable energy mix, improving an offshore sector that is, apparently, less controversial or disrupted than its bottom-fixed counterpart (in terms of cohabitation with other maritime uses and preservation of marine ecosystems). To better understand the socio-political impediments to the implementation of floating wind farms, we conducted a study of the local governance process around the implementation of one of the first floating offshore wind farms in France, in the Bay of Biscay. This study focuses on the analysis of perceptions of floating OWF impacts by decision-makers involved in the validation process of the Environmental Impact Assessment: how do these decision-makers perceive, value and relate to the marine ecosystem in the presence of a floating OWF? How do ecological factors shape decision-making, and what ecological factors are involved? The paper applies a network perspective in the analysis of the local marine social-ecological s

The consequences of climate change for marine organisms are now well-known, and include metabolism and behavior modification, distribution area shifts and changes in the community. In the Bay of Biscay, the potential environmental niches of subtropical non-indigenous species (NIS) are projected to expand as a response to sea temperature rise by the mid-century under the RCP8.5 climate change scenario. In this context, this study aims to project the combined effects of changes in indigenous species distribution and metabolism and NIS arrivals on the functioning of the Bay of Biscay trophic network. To do this, we created six different Ecopath food web models: a “current situation” trophic model (2007–2016) and five “future” trophic models. The latter five models included various NIS biomass combinations to reflect different potential scenarios of NIS arrivals. For each model, eight Ecological Network Analysis (ENA) indices were calculated, describing the properties of the food web resulting from the sum of interactions between organisms. Our results illustrate that rising temperature increases the quantity of energy passing through the system due to increased productivity. A decrease in the biomass of some trophic groups due to the reduction of their potential environmental niches also leads to changes in the structure of the trophic network. The arrival of NIS is projected to change the fate of organic matter within the ecosystem, with higher cycling, relative ascendency, and a chain-like food web. It could also cause new trophic interactions that could lead to competition and thus modify the food-web structure, with lower omnivory and higher detritivory. The combined impacts (increasing temperatures and NIS arrivals) could lower the resilience and resistance of the system.

There is a growing interest in the development of offshore wind farms to provide a sustainable source of renewable energy and contribute to the reduction of carbon emissions. In parallel, there is a need to better understand the effects of these installations on coastal marine ecosystems and identify potential sea use conflicts, especially when the area is subject to access restrictions. This study investigated the effects of a spatial closure during the exploitation phase of an offshore wind farm in the extended Bay of Seine (English Channel, France) using Ecospace, a spatially and temporally explicit module of Ecopath with Ecosim. To address this question, simulations were conducted through the evaluation of “what-if scenarios” to assess the effectiveness of a fishing exclusion zone inside and surrounding the offshore wind farm. Several biomass, catch and trophic level-based indicators were calculated to evaluate how the exclusion zone could affect fishing activities and main components of the food web. All the indicators were estimated in the extended Bay of Seine and summarized by sub-area. Findings suggested that the spillover effect could mitigate the negative impact of access loss on fishing activities, in a scenario of simulated closure of the area of the wind farm. The Ecospace model predicted an increase of catches (up to 7% near the wind farm) and a slight increase in the proportion of high trophic level species. However, the influence of spillover effects is limited in space and the expected increase of biomass and catches are highly localized in areas around the offshore wind farm installations. At the scale of the Bay of Seine, further analysis of the spillover effects revealed a spatial pattern and suggested that the implementation of an exclusion zone inside the offshore wind farm could concentrate highly mobile predators.

A combination of modelling tools was applied to simulate the impacts of the future Courseulles-sur-mer offshore wind farm (OWF) construction (Bay of Seine, English Channel) on the ecosystem structure and functioning. To do so, food-web models of the ecosystem under three scenarios were constructed to investigate the effect caused by the OWF of added substrate (reef effect), fishing restriction (reserve effect), and their combined effect. Further, Ecological Network Analysis indices and Mean Trophic Level were derived to investigate their suitability for detecting changes in the ecosystem state. Our analysis suggests changes in the ecosystem structure and functioning after the OWF construction, the ecosystem maturity was predicted to increase, but no alterations in its overall resilience capacity.