Environmental impacts of seaweed cultivation: kelp farming and preservation

This chapter provides an overview of the environmental impacts of the supply chain for preserved seaweed. The supply chain includes the hatchery, marine infrastructure, deployment of juveniles and monitoring during cultivation (grow-out of seaweed), harvest, transport back to shore and preservation of the biomass. The chapter starts with a short overview of the life cycle assessment (LCA) methodology, and how it can be used to quantify the environmental impacts of seaweed supply chains. After a discussion of the overall environmental impacts of the preserved seaweed supply chain, the chapter focuses on specific life cycle stages: spore preparation and seeding of juvenile seaweed onto string in the hatchery, seaweed cultivation, harvesting preservation and storage of harvested seaweed. The chapter ends with a summary and discussion of future trends in the subject.

Technical challenges for offshore cultivation of kelp species: lessons learned and future directions

Traditional kelp farming methods require a high amount of labor and are limited in geographic distribution – occurring mainly in nearshore, sheltered sites. To address growing global demand for sustainable biomass, the continued expansion of kelp cultivation will most likely have to move further offshore. Although many offshore cultivation trials have been done over the last 50 years, few were sufficiently robust to be viable in exposed and deep-water areas. In the North Atlantic Ocean, a Faroese company developed and tested a structural farm design that has survived in open-ocean conditions since 2010. The durable structure has withstood harsh weather events common in the Faroe Islands and thereby presents a potential strategy and method for moving kelp farming further offshore. This paper describes the primary challenges of offshore kelp farming and provides an overview of work previously done. Ultimately, the improved productivity, system survivability and scalability the MacroAlgal Cultivation Rig (Faroe Islands) and the BioArchitecture Lab cultivation grid (Chile) represent state-of-the-art and powerfully transformative strategies to pursue large-scale offshore farming to support mass production of kelp in the near future.