The fate of seaweed-derived DOC - mineralization or sequestration?

We aim to study the bioavailability and turn-over of seaweed-derived dissolved organic carbon (DOC) from a range of morphologically distinct seaweeds to evaluate their role for carbon (C) sequestration as a CO2-mitigation tool. Seaweed systems cover 6-7×106 km2 globally and contribute with a net primary production (NPP) of 1.3 Pg C yr-1, equal to 1-2% of the global NPP. Part of that C is buried for centuries or millennia as dead seaweed material and represents thus C removed from the atmosphere. About 25% of the C fixed by seaweeds is however released as DOC from living and senescing seaweeds and it is presently unknown whether that C is prone to fast biological turnover or if it contains refractory components that may resist decomposition and thus contribute to C-sequestration.