Sebastian Jian Ernst Krause, Sara Matsumura, Chance James English , Craig A Carlson, Robert Miller, David Valentine, David Siegel

One promising carbon dioxide removal (CDR) strategy to achieve negative emissions of carbon dioxide is the sinking of farmed seaweed into the ocean where it may be sequestered. Methods to quantify the sinking rates, degradation rates and the release of degradation products from kelp is fundamental to understanding the durability of the strategy if applied to scale. The aim of this white paper is to describe the methods we plan to use to determine the sinking rates, quantify kelp degradation and the release of kelp degradation products such as particulate and dissolved organic carbon, as well as dissolved inorganic carbon. The methods design is guided by previously published methods and considers the type of packaging and conveyance of kelp biomass as well as, the necessary parameters needed to model this CDR strategy to scale. This white paper will show our planned approach includes the combination of both laboratory and field-based experiments to determine each of these parameters, and provide foundational guidelines in future work to test the durability of this CDR strategy.