Mapping the global mass flow of seaweed: Cultivation to industry application

The global flows of cultivated seaweed were estimated for the year 2019 using a combination of literature review, assumptions, and simple conservation of mass calculations. Red seaweeds were found to be the largest contributors to the hydrocolloids industry, for both food and non-food applications. Carrageenan-containing species were found to be the largest contributors to both food (62%) and non-food (55%) hydrocolloids and are the primary source for water gels, which make up 27% of non-food hydrocolloids, followed by pet food (16%), toothpaste (6%), and others (6%). Carrageenan also accounts for almost all meat products, which make up 35% of the food hydrocolloid industry, and dairy products, which make up 26%. Agar-containing seaweeds are used in confections (10% of food hydrocolloids), baking (9%), and other (2%) and make up 15% of non-food hydrocolloids. Porphyra (nori) is cultivated for direct consumption and makes up 23% of direct food consumption. Cultivated brown seaweeds were found to comprise Laminaria/Saccharina for alginate production (30%), Laminaria/Saccharina for direct consumption (44%), and Undaria for direct consumption (16%). About half of the alginates produced make up 18% of food hydrocolloids, and the other half is used in non-food hydrocolloids comprising technical grades (28% of non-food) and animal feed (3%). The results are discussed in the context of emerging markets for seaweed and the potential for seaweeds as a substitute for staple foods, and the environmental impact of seaweed farming is explored through a review of life cycle assessment studies.