Insight into the composition and permanence of biochar produced from pyrolysis of land plant and macroalgae biomass

Production of biochar from pyrolysis under anoxic or oxygen-deficient conditions of agricultural waste products and aquaticbiomass has increasing focus due to a wide range of beneficial applications of biochar. The formation of biochar can reduce CO2emissionsby sequestration ofcarbon fromthe biosphere pool to the geological carbon cycle with long-term storage potential. Biochar is also a byproduct of sustainable biofuel production as a substitute to fossil fuel. Characterization of biochar, including carbon stability in the soil, has primarily been based on elemental composition and incubation experiments. However, organic petrographic and geochemical methods are preferable since they are standardized, well-established and can set biochar properties into the context of the geological bacterial and heat-induced organic carbon evolution in the Earth’s crust (Petersen et al., 2023).