The “Sustainable Cultivation of Seaweed” (SUSCULT) project has come to an end, with interesting outcomes and plenty of ideas for future research. The project, funded by the Nordic Council of Minsters, explored the potential of seaweed cultivation in the Nordic region based in literature research and by conducting small-scale tests. Based on already-existing commercial production, the species with the best potential in the Atlantic coasts of the Nordic countries are sugar kelp (Saccharina latissima) and badderlocks (Alaria esculenta). These species are already produced and yielding 70 to 200 tons fresh weight (FW) per hectare annually. In the Baltic Sea area, bladder wrack (Fucus vesiculosus) and the green sea lettuce (Ulva intestinalis) has been identified as the most promising species. At present there are pilot scale cultivation trials but no full-scale commercial production taking place in the Baltic Sea.

SUSCULT was led by the Finnish Environmental Institute and included partners from Denmark, Estonia, Iceland, Norway and Sweden. In each area, partners set out small-scale cultivation tests focused on the low-tech solution of putting out substrate (lines) to see what and how much seaweed would naturally settle and grow on the lines. This is in contrast to what is generally done in seaweed cultivation, which is seeding the lines in a laboratory. There were variations across the partners, but it seems filamentous brown algae, Pilayella sp and Ectocarpus sp were the dominant groups both in the Baltic Sea and Atlantic coasts. The growth potential was relatively low with an optimistic estimate of 10 tons FW per hectare, and this study confirms that pre-seeding the lines be-fore putting them out to sea would be required for any commercial production.

The UW team of SUSCULT was lead by Dr. Catherine Chambers, research manager, and involved two UW students Kerstin Frank and Nick Hoad who worked as interns on the project, and UW Alum Justin Brown who worked as a research assistant in cooperation with Eldey Aqua, a local seaweed start-up company. The research company BioPol in Skagaströnd also took part in the research. The team designed and deployed the test lines, monitored growth, and collected the final samples which were weighed and sent for laboratory analysis. Heavy metals, specifically cadmium and arsenic, occur naturally in Icelandic waters and were of particular interest in the project. The seaweed growing on the lines did not have amounts of these metals that exceed European food safety standards, although levels of arsenic were slightly elevated. This can be taken as positive news for potential seaweed farmers but more research is needed.

In another angle, Kerstin conducted research on the legal aspects of seaweed cultivation, her final report has been circulated among Icelandic start-up companies and decision-makers interested in supporting seaweed cultivation in Iceland. Details from that report can be found here.

Interest in seaweed continues to grow in Iceland and we hope to be involved in future research projects like SUSCULT that address the interdisciplinary aspects of seaweed cultivation!