Assessing the viability of multi-use Macroalgae Aquaculture within Offshore Wind Farms

Project Description:

Seaweed is rich in molecules and compounds of interest, boasting applications across numerous industries, such as cosmetics, pharmaceuticals, biofuels, and the agriculture sector (Garcia-Poza et al. 2020). As a result, the European market for seaweed is estimated to reach €9.3bn by 2030. To achieve this however, macroalgae aquaculture must scale up production to reduce the cost of seaweed products and develop economies of scale – for this to be viable, further utilisation of marine space and industrialisation of farming techniques would be required (Fletcher 2020).

The rapid development of the Offshore Wind Industry brings with it a plethora of opportunities for other marine industries. By 2030 offshore wind farms are expected to cover 8,000km² of the North Sea (Fletcher 2020). Current concerns over the growing demand for marine space has resulted in various ideas around colocation of infrastructure for multiple industries (Burg et al. 2020). Co-locating offshore wind infrastructure with macroalgae farms would satisfy the production needs by providing the required area for commercial production, as well as enabling the reduction of cost through shared labour and equipment (Seaweed for Europe 2020).

Offshore wind operators are required to undertake environmental mitigation and compensation under the UK Conservation of Habitats and Species regulations 2017, and the EU Habitats directive. Macroalgae has also demonstrated benefits for the environment through carbon cycling, supporting high levels of diversity, and provision of nursery habitats, although the role of seaweed aquaculture in providing these functions has received limited research attention. Moreover, the placing of seaweed aquaculture above generally mixed sediment habitats will result in a pulse of detrital material (via thallus erosion and dislodgement from growing lines) to the benthos, which would not occur without the presence of the aquaculture facility. This could positively influence benthic communities by increasing food and decreasing competition, alternatively it could lead to anoxic conditions with negative impacts on benthic diversity. The collocation of offshore wind with seaweed aquaculture could therefore enable offshore wind operators to demonstrate their efforts for improving the environment (but see counter-argument above) as well as potentially supporting other stakeholders (e.g. fishing industry), which may benefit from the turbines and seaweed acting as fisheries aggregation devices.

Not all Offshore wind sites would be suitable for aquaculture, however. Determining which sites hold optimum environmental conditions while also having minimal effect on external stakeholders is needed, as this will enable the future planning of these multi-use areas. By communicating and addressing stakeholder concerns prior to development, the barriers and risks of this concept can be identified (Burg et al. 2020).

Current macroalgae aquaculture sites are usually small – medium in size (typically 0-5 x 200 m lines) and shown to have minimal risk to the surrounding environment if the site is managed correctly (Campbell et al. 2019). As the UK and Europe begin to scale up production however, there is a need to gain a wider understanding on the direct and cumulative impacts that a commercial, large scale (>50 x 200 m lines) aquaculture farm would have (Campbell et al. 2019).

The objectives of this PhD are to:

• Analyse the potential for multi-use, including the current barriers and risks to deployment, as well as stakeholder analysis to gain a wider understanding of industry opinions towards multi-use areas.
• Undertake co-location analysis, identifying current offshore wind sites suitable for macroalgae aquaculture around the UK and Europe.
• Determine the effects of commercial offshore macroalgae aquaculture for biodiversity and the environment.