Macroalgae cultivation

Rymättylä & Tvärminne, Finland

Macroalgae have been used on a small scale for centuries as animal feed and fertilizer, but with increased efficiency in agriculture and development of artificial fertilizers these aspects have lost some of their significance. On the other hand, new uses of algae are being developed. An example is the extraction of alginate from macroalgae, which is then used in a number of products from toothpaste to products for the textile printing industry.

Most of the algae used today comes from collection of natural seaweed. This can be done sustainably, but there is a limit to how much can be harvested before the coastal ecosystem will be affected. Cultivating macroalgae could be an alternative that would not affect the ecosystem in the same way and might in fact have a beneficial environmental impact, taking up nutrients from the sea in places where excess loading of nutrients is an environmental problem.

SUBMARINER will carry out a pilot study to assess the possibility to cost-efficiently cultivating macroalgae in the northern Baltic Sea. This could potentially be the start of algal raw material production and has the potential for alleviating the eutrophication problem in this region. The aim is to demonstrate the potential of macroalgal cultivation for producing biomass for industrial applications like bioenergy and removing excess nutrients.

The planned pilot scale facilities consist of net and rope -type cultivation systems. These are placed in various locations covering different degrees of exposure, nutrient concentration and salinity. One site will be located close to fish farms, another in waters with less nutrient loading. The specially-designed net and rope system will be tested as a substrate for cultivation of fast-growing, annual green algae (e.g. Ulva sp.). Analyses will then relate to abundance, dry weight, nutrient content, carbon fractions, heavy metals, epiphytes and environmental variables.