Chance James English , Craig A Carlson

Seaweed cultivation for atmospheric CO2 sequestration requires full accounting of net primary production (NPP). In addition to large amounts of observable biomass produced, a fraction of NPP is released as dissolved organic carbon (DOC), which can fuel heterotrophic metabolisms or resist remineralization and contribute to carbon export and sequestration. We currently lack the ability to predict the amount of NPP released as DOC, and published estimates range from <1 to 62%. This white paper describes technical and experimental considerations needed to quantify and characterize DOC released by seaweeds as well as designs to determine the fraction which is recalcitrant. Additionally, we recommend key variables that should be used to parameterize DOC production for its inclusion in large-scale seaweed farm models.