CliPA: Climate-neutral offshore production of algal biomass

Interdisciplinary feasability study between Univ. Rostock, GEOMAR Kiel and Univ. Kiel (DBU 1.3.2023 - 28.2.2026)

Project Summary:

This is a feasibility study on the sustainable production of biomass in the sea, which reduces ongoing nutrient enrichment in the Baltic Sea and at the same produces time fertiliser and energy in an environmentally friendly way. The project is being carried out in close cooperation between science and society. The long-term goal is to reduce nutrients and carbon by macroalgae in offshore cultures and to use the biomass produced as a recyclable material, fertiliser and/or biogas raw material on land, with the initial focus on the bladderwrack (Fucus vesiculosus). Some of these applications reduce the nutrient input by agriculture, others reduce land use for crops (e.g. maize, oilseed rape) that are mainly used for production, rape), which are mainly used to produce biomass as an energy source. The following focal points will be investigated as work packages (WP) during the project:

WP1 - Optimisation of the cultivation of macroalgae on artificial hard substrates that can be used for offshore cultivation.

WP2 - Screening of suitable techniques for offshore bladderwrack cultivation (anchoring, substrates, growth and harvesting rhythms).

WP3 - Qualitative and quantitative assessment of the ecosystem services of bladder wrack cultures (nutrient depletion, oxygen production, reduction of ocean acidification through carbon dioxide through carbon dioxide uptake, biomass production, biodiversity enhancement, etc.).

WP4 - Development of land-based use for the harvested bladderwrack biomass as natural fertiliser, raw material for biogas production or high-value material for cosmetics,

WP5 - Assessment of environmental environmental benefits, costs, funding opportunities, market appropriation.

WP2 and WP4, in particular, will be carried out in close cooperation with regional stakeholders (fishermen, wind farm operators, farmers, biogas plant operators) and government institutions (BSH, BfN, Thünen Institute). The aim is to assess the opportunities and possibilities of large-scale macroalgae offshore cultures in the brackish Baltic Sea with regard to:

I. the creation of a regionally closed nutrient cycle to reduce firther enrichment in the south-western Baltic Sea,

II. the production of rennewable raw materials without fertiliser, pesticide, and watering as typically employed in landside cultures, and

III. the examination of surplus income opportunities for fishermen and saving opportunities for farmers.

The multifaceted potential of ecosystem services of open-land bladderwrack cultures is thus being investigated experimentally in the Baltic Sea for the first time, and contributes to the UN Sustainable Development Goals.

Coordinators: Ulf Karsten (Rostock), Martin Wahl (Kiel)

Advisory board

Project partners

Associated agencies

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Coordination & Funding


Prof. Dr. Ulf Karsten, Uni Rostock

Prof. Dr. Martin Wahl, GEOMAR Kiel



Deutsche Bundesstiftung Umwelt DBU