Carbon sink potential and environmental benefits of seaweed: A case study of the seaweed cultivation industry on China coast

Abstract

Initiatives to mitigate climate change have recently aroused great interest in the role of natural carbon sinks in coastal ecosystems. Seaweeds are widely distributed in the world and represent a large biomass. Since they are part of the global carbon reserves, they remove carbon dioxide and influence climate change. Using the recent 20 years of seaweed mariculture in China's coastal areas as a case, this paper quantifies the carbon storage in cultivated seaweed biomass, and evaluates the carbon sink potential, the remediation ability of nitrogen and phosphorus and other environmental benefits. The carbon sink potential of cultivated seaweeds exhibits a rising trend from 2000 to 2019. The total carbon, nitrogen, and phosphorus removal amount of seaweed were 3,551,754.9 ± 177,587.75, 297,772.25 ± 14,888.61, 39,967.15 ± 1998.36 tons according to the seaweed cultivation yield in China coast. The total benefit of carbon sequestration was 22,405.67 ± 259.59 million CNY, and the average benefit was 1120.28 ± 263.27 million CNY, with the average annual growth rate of 4.00%. The total environmental benefit was 1,962,020.88 ± 22,747.42 million CNY, and the average benefit was 98,103.04 ± 23,073.08 million CNY, with the average annual growth rate of 4.00%. The present study illustrates distinctly the ecological value of large-scale cultivated seaweeds in increasing marine carbon sequestration and resolving offshore environmental issues, which is an efficient approach and comparable to other key marine ecosystems. Based on the carbon sink role of seaweed mariculture, and with the goal of global carbon neutrality, more attention should be paid to the carbon sink capacity of large-scale seaweed cultivation industry and be vigorously developed worldwide.