Seaweed resources as a source of carbon fixation

Approximately 2 gigatons of carbon a year is estimated to diffuse across the air-sea interface into the dissolved CO2 pool of surface ocean water. The total area of algal and seagrass beds along the coasts of Japan is 2,012 km2.We are currently estimating the macrophyte production along the coasts of Japan by estimating the annual net production and carbon content, and it is likely to be a value of ca. 2,700,000 tons of carbon a year. Additionally, the Japanese people have historically used seaweeds as food source.

Economically important genera (Porphyra, Laminaria, Undaria etc.) are cultivated and harvested, with an estimated annual production of cultivated seaweeds of 530,000 tons wet weight. The total amount of annual carbon absorption by seaweed cultivation is estimated to be approximately 32,000 tons, corresponding to 1.2 ％ of the annual macrophyte production along the coasts of Japan. It is also well known that seaweeds have a positive impact on moderately eutrophic water by absorbing nutrients from surrounding waters. Seaweed resources are an important source of carbon fixation.