Together with our partners from GEOMAR, Seafields and Carbonwave, and with support from BASF, our group at AWI will develop novel monitoring tools to quantify and verify carbon sequestration by Sargassum aquafarms in the open ocean. The C-CAUSE consortium addresses one of the most important challenges of decarbonization - the provision of biological, renewable carbon feedstocks for the chemical industry. Our idea is to use marine algae that do not require land, freshwater or artificial fertilizers and absorb carbon through photosynthesis. The vision is to create huge aquafarms with the fast-growing, free-floating marine algae Sargassum in the open sea. To operate Sargassum aquafarms for large-scale carbon sequestration, we need to find the optimal trade-off between a fast growth rate and a high carbon to nutrient ratio and apply innovative techniques to monitor large ocean areas.

Our group will conduct incubations that add nutrients recovered through post-harvest processing steps and measure carbon uptake and nutrient storage in Sargassum biomass using stable isotopes. Our partners will process the algae to produce ethanol through fermentation and biomethane through anaerobic digestion. The ethanol can be used to produce durable engineering plastics that store carbon for decades, and the methane can be used as a fuel for operations, creating a carbon-negative approach that actively sequesters CO2 into valuable products.
 

If you want to learn more about the big picture, you can watch the full presentations of our mentor Prof. Em. Victor Smetacek under this link:

https://ml.zmml.uni-bremen.de/series/654227e0d42f1c750a8b457a

MacroCarbon, an AWI spin-off, is a Gran Canaria-based company developing a supply chain for the large-scale cultivation of drifting algae to produce bio-based feedstocks (e.g. bionaphtha) for the chemical industry and biochar for permanent carbon sequestration. Our approach is unique as it covers the entire value chain from aquaculture to product. We will apply a biorefinery concept to extract high-value products from the algae before converting them into biofuels and biochar through pyrolysis. Our aim is to build the processing plant on a ship or platform close to the aquafarm to avoid costly transportation of the wet algae biomass. In this way, we will develop an integrated supply chain that will enable a global role for an algae-based blue circular bioeconomy that will significantly contribute to the de-fossilization of our current system and help mitigate climate change.