Characterisation of underwater operational sound of a tidal stream turbine

Risch, Denise; Geel, Nienke van; Gillespie, Douglas; Wilson, Ben

doi:10.1121/10.0001124

Cited by 18 publications

(17 citation statements)

References 29 publications

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“…We do not know from these data whether the noise is transmitted to our hydrophones through the steel turbine support structure and how much of the noise is present in the water column, which might alert animals to the presence of the turbine. Measured in-water noise levels around the turbine using drifting hydrophones showed that the 20kHz noise present in our data is higher than ambient noise levels out to a range of 200m and that lower frequency sounds generated by the turbine are 5dB above ambient levels over 2km from the turbine [27].…”

Section: Plos Onementioning

confidence: 46%

Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

et al. 2020

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A wide range of anthropogenic structures exist in the marine environment with the extent of these set to increase as the global offshore renewable energy industry grows. Many of these pose acute risks to marine wildlife; for example, tidal energy generators have the potential to injure or kill seals and small cetaceans through collisions with moving turbine parts. Information on fine scale behaviour of animals close to operational turbines is required to understand the likely impact of these new technologies. There are inherent challenges associated with measuring the underwater movements of marine animals which have, so far, limited data collection. Here, we describe the development and application of a system for monitoring the three-dimensional movements of cetaceans in the immediate vicinity of a subsea structure. The system comprises twelve hydrophones and software for the detection and localisation of vocal marine mammals. We present data demonstrating the systems practical performance during a deployment on an operational tidal turbine between October 2017 and October 2019. Three-dimensional locations of cetaceans were derived from the passive acoustic data using time of arrival differences on each hydrophone. Localisation accuracy was assessed with an artificial sound source at known locations and a refined method of error estimation is presented. Calibration trials show that the system can accurately localise sounds to 2m accuracy within 20m of the turbine but that localisations become highly inaccurate at distances greater than 35m. The system is currently being used to provide data on rates of encounters between cetaceans and the turbine and to provide high resolution tracking data for animals close to the turbine. These data can be used to inform stakeholders and regulators on the likely impact of tidal turbines on cetaceans.

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Section: Plos Onementioning

confidence: 46%

Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

et al. 2020

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“…The functions that we used have been built inferring these responses from other sources of noise rather than OWTs because of current lack of data. Our results suggested the importance of quantitative measures of noise produced (Risch et al, 2020;Tougaard et al, 2020;Stöber and Thomsen, 2021) in relation with species specific responses (Teilmann and Carstensen, 2012).…”

Section: Discussionmentioning

confidence: 61%

“…Here the potential impact of noise was simulated by a response function using preliminary results from a recent study showing dislocation of harbor seal up to 2 km from a tidal turbine noise source (Joe Onoufriou and Laura Palmer, St Andrews University, EIMR2020 conference presentations, April 21st-23rd 2020) (Figure 3 and Supplementary Figure 5). This assumption was reinforced by recent studies that showed that the low frequency noise can be 5 dB higher than ambient noise at 2.3 km distance from an operational tidal turbine (Risch et al, 2020) that can cause significant avoidance (78%) at 140 m from the source (Palmer et al, in review): however tidal turbines produce considerably louder noise than wind farms. Harbor seals can show significant displacement (up to 25 km) from the wind farm construction site during piling activity, however, not significant displacement during construction as a whole was found (Russell et al, 2016).…”

Section: Discussionmentioning

confidence: 98%

Modeling Small Scale Impacts of Multi-Purpose Platforms: An Ecosystem Approach

et al. 2021

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Aquaculture and marine renewable energy are two expanding sectors of the Blue Economy in Europe. Assessing the long-term environmental impacts in terms of eutrophication and noise is a priority for both the EU Water Framework Directive and the Marine Strategy Framework Directive, and cumulative impacts will be important for the Maritime Spatial Planning under the Integrated Maritime Policy. With the constant expansion of aquaculture production, it is expected that farms might be established further offshore in more remote areas, as high-energy conditions offer an opportunity to generate more power locally using Marine Renewable Energy (MRE) devices. A proposed solution is the co-location of MRE devices and aquaculture systems using Multi-Purpose Platforms (MPPs) comprising offshore wind turbines (OWTs) that will provide energy for farm operations as well as potentially shelter the farm. Disentangling the impacts, conflicts and synergies of MPP elements on the surrounding marine ecosystem is challenging. Here we created a high-resolution spatiotemporal Ecospace model of the West of Scotland, in order to assess impacts of a simple MPP configuration on the surrounding ecosystem and how these impacts can cascade through the food web. The model evaluated the following specific ecosystem responses: (i) top-down control pathways due to distribution changes among top-predators (harbor porpoise, gadoids and seabirds) driven by attraction to the farming sites and/or repulsion/killing due to OWT operations; (ii) bottom-up control pathways due to salmon farm activity providing increasing benthic enrichment predicated by a fish farm particle dispersal model, and sediment nutrient fluxes to the water column by early diagenesis of organic matter (recycled production). Weak responses of the food-web were found for top-down changes, whilst the results showed high sensitivity to increasing changes of bottom-up drivers that cascaded through the food-web from primary producers and detritus to pelagic and benthic consumers, respectively. We assessed the sensitivity of the model to each of these impacts and the cumulative effects on the ecosystem, discuss the capabilities and limitations of the Ecospace modeling approach as a potential tool for marine spatial planning and the impact that these results could have for the Blue Economy and the EU’s New Green Deal.

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“…Harbour porpoises have previously been shown to exhibit behavioural changes or spatial avoidance responses to anthropogenic noise sources, including operation of acoustic deterrent devices (Johnston, 2002) and pile driving during installation of offshore wind turbines (Brandt et al, 2011). Independent measurements obtained using drifting hydrophones showed high‐amplitude noise associated with operation of the turbine in the 50–1,000 Hz band and at 20 kHz (Risch et al, 2020). Harbour porpoise hearing is relatively poor below 1,000 Hz; however, the 20 kHz component of the turbine noise falls within the most sensitive hearing range for harbour porpoises (Kastelein, Helder‐Hoek & Van de Voorde, 2017) and was detectable above ambient noise levels up to 200 m from the turbine (Risch et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Independent measurements obtained using drifting hydrophones showed high‐amplitude noise associated with operation of the turbine in the 50–1,000 Hz band and at 20 kHz (Risch et al, 2020). Harbour porpoise hearing is relatively poor below 1,000 Hz; however, the 20 kHz component of the turbine noise falls within the most sensitive hearing range for harbour porpoises (Kastelein, Helder‐Hoek & Van de Voorde, 2017) and was detectable above ambient noise levels up to 200 m from the turbine (Risch et al, 2020). It is therefore conceivable that this noise may drive the observed avoidance response in this study.…”

Section: Discussionmentioning

confidence: 99%

Harbour porpoise (Phocoena phocoena) presence is reduced during tidal turbine operation

Palmer

Gillespie

Macaulay

et al. 2021

Aquatic Conservation

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Uptake of tidal turbine technology to generate renewable energy has been partly limited by poor understanding of ecological impacts, including the potential for collisions between cetaceans and rotating turbine blades. To address this concern, it is necessary to identify whether cetaceans behaviourally respond to operating turbines. A turbine in Scotland was instrumented with hydrophones to detect cetacean vocalizations. A generalized additive model was used to investigate temporal variability in harbour porpoise presence close to the turbine. As there were incidentally periods when the turbine was not operating, it was possible to determine the effect of blade rotation, whilst accounting for the potentially confounding effect of tidal flow. Harbour porpoise presence varied intra‐annually, diurnally and with tidal state. Peak presence occurred during winter (September–February), at night and at high flow speeds on the flood tide. Porpoises exhibited significant avoidance of the tidal turbine when it was operating; avoidance increased with flow speed, whereby mean porpoise presence was reduced by up to 78% (95% CIs, 51%, 91%) on the flood tide and up to 64% (95% CI, 3%, 91%) on the ebb tide. The temporal variability in encounter rate in the present study highlights that collision risk assessments assuming static densities probably fail to capture the temporal variability of collision risk. Future studies should conduct long‐term baseline monitoring to derive encounter rates at larger spatio‐temporal scales and as a reference from which to measure change in habitat use. It is also critical that the generality of the avoidance rates presented here is assessed for other sites, turbine types, array sizes and cetacean species. As the tidal industry expands, it will be important to reconcile the benefits of avoidance responses from a collision risk perspective with potential chronic effects of displacement from, or barriers between, important habitats.

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Characterisation of underwater operational sound of a tidal stream turbine

Cited by 18 publications

References 29 publications

Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

Modeling Small Scale Impacts of Multi-Purpose Platforms: An Ecosystem Approach

Harbour porpoise (Phocoena phocoena) presence is reduced during tidal turbine operation

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