How noisy is too noisy? Understanding how underwater noise from offshore wind turbines can impact the environment.

In July 2013 the RV Princess Royal was home to a group of UK underwater sound specialists, called the Bio-Acoustic Research Consortium (BARC). This new project is led by Dr Per Berggren from Newcastle University’s School of Marine Science and Technology and it brings together a range of noise specialists, ecologists and industry professionals with a common aim: to better understand the impact of underwater noise on marine ecosystems.

The consortium has attracted grant funding from the Natural Environment Research Council’s Marine Renewables Knowledge Exchange Programme to explore the environmental challenges associated with offshore wind development, an industry that continues to grow rapidly. The Newcastle Institute for Research on Sustainability (NIReS), also supplied a small grant towards equipment costs which has funded the purchase of six hydrophones, called C-Pods, for detecting marine mammals. It is hoped the knowledge gained from the project can be fed directly back to industry to assist them in minimising their environmental impact.

We carried out a week of field work in July, focussing on the proposed Narec Offshore Wind Demonstration Site which lies around 6km off the coast of Blyth, Northumberland. There will be up to 15 turbines built at this site, with a maximum output of 99.9 megawatts, enough to power approximate 30,000 homes. There is already an offshore tower at the site, installed in November 2012, which is collecting data on wind speed and climate for the prospective wind farm developers.  The BARC team carried out preliminary noise monitoring work during the installation of this mast last winter. Offshore wind is seen as an important part of the UK’s future energy strategy, so it’s important we fully understand the impact of these structures on the environment.

Underwater noise associated with offshore wind developments can change the ecosystem around the turbines in ways that are not fully understood. Turbines are typically installed using a method called piling. This involves hammering heavy steel cores into the sea bed which provide a platform for the generating equipment above the surface. The technique is very loud and creates radiating waves of sound of a very high amplitude. Studies in other countries have shown that this sound has very immediate impacts on marine mammals, fish and invertebrates which will often leave the area or be stressed by the noise. The turbines also vibrate and make noise during their operation, which adds to the other existing man made noise in the area from fishing and onshore development.

The BARC brings together specialists in marine mammal ecology (Newcastle), marine microbiology (Newcastle/NIReS) fish behaviour and ecology (Bristol and Exeter), underwater noise (Swansea) and noise sensing technology (Industry) for the first time. The work we carried out in July near Blyth was about collecting baseline measurements, so understanding the condition of the environment prior to construction commencing. To do this we used many different field techniques and recording equipment. We are using a special acoustic tank at Newcastle University to calibrate this equipment to ensure the data from the various equipment is comparable. Newcastle deployed several technologies for recording the underwater sounds made by mammals. We used C-Pods, which are sensors that can be left in the water moored to the sea bed, to detect porpoise and dolphin clicks. These provide excellent data over long periods of time at specific locations, known as temporal data. We also used a towed hydrophone system to listen for marine mammals, this is useful to understand variations in cetacean numbers across the survey areas, known as spatial data. We used visual observers on top of the ship with binoculars to record the animals we could see at the surface too. We had sightings of Harbour Porpoise (Phocoena phocoena) and White-Beaked Dolphin (Lagenorhynchus albirostris) during the week of field work. Dr Lynsay Blake from NIReS carried out a microbiological assessment of the site to examine the bacteria that live in the sediments near the proposed turbines as microbial changes in response to high amplitude underwater noise have not previously been studied.

Our partners from other universities used trawl nets, sediment grabs and a range of sensing technologies to conduct their surveys. All together we spent four full days at sea collecting data using a range of equipment and techniques. Between us we have built up a comprehensive picture of the ecosystem around the offshore wind site prior to its construction. The challenge now is to design experiments that will allow us to continue monitoring the site during the later phases of the development, including construction.

This work is important as we need to understand ecosystem level changes that occur in response to offshore wind sites. Studying one particular species can provide a great deal of information, but as we all know, all animals in a particular environment are connected though complex food webs and other ecological factors. When you affect one species that will affect others indirectly. We are looking at a range of species responses at the development site, from bacteria at the base of the food chain to mammals at the top. This will provide a greater understanding of how these complex interactions change in response to offshore noise.

We will report back on how this work progresses in the next few months and years, so keep watching the blog. For more information on the project, contact Dr. Per Berggren, per.berggren@ncl.ac.uk or Simon Laing, E-mail: simon.laing@ncl.ac.uk.

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1 Response to How noisy is too noisy? Understanding how underwater noise from offshore wind turbines can impact the environment.

  1. Pingback: How Noisy is Too Noisy? | Eco Books 4 Kids

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