The efficiency of storing carbon in seagrass beds is 90 times higher than that of forests, and they have the functions of water purification and regulation. They are a natural barrier for protecting the coast. In midsummer, strolling along the coast of the Yellow Sea and Bohai Sea, one can see seagrass beds blooming with flowers. Seaweed plants absorb sunlight and dance with the waves in the seawater. Seaweed is a higher plant that evolved from terrestrial plants to adapt to marine environments, and is the only type of angiosperm on Earth that can fully live in seawater. Except for Antarctica, seagrass is found in shallow coastal waters around the world. One or several seagrasses grow together in patches, forming a vast and soft 'underwater grassland', also known as a 'seagrass bed'. Seaweed beds, mangroves, and coral reefs are three typical nearshore marine ecosystems. Seaweed beds are one of the most efficient carbon capture and storage systems, with a carbon storage efficiency 90 times higher than forests and a carbon sequestration time of up to thousands of years. The existing seagrass beds worldwide cover an area of approximately 170000 square kilometers and can absorb over 100 million tons of carbon dioxide annually. The reason why seagrass beds can sequester carbon is due to their ability to absorb inorganic carbon from the environment through photosynthesis, efficiently fix and convert it into organic carbon, and accumulate it. At the same time, seagrass beds have strong ability to capture suspended solids, stable sedimentary environments, and extremely low decomposition rates of litter, which enable them to effectively sequester carbon in the long term. Although the distribution area of seagrass beds worldwide accounts for less than 0.2% of the ocean area, they contribute over 10% annually to the burial of organic carbon in the ocean, making them an important blue carbon sink and reservoir. In addition to its strong carbon sequestration capacity, seagrass beds also have water purification and regulation functions such as absorbing nutrients and heavy metals from water bodies, reducing suspended solids concentration in seawater, and preventing or slowing down beach and coastal erosion. They are a natural barrier for protecting coasts and play an important role in embankment disaster reduction. Seaweed beds are still an important source of food for benthic animals. Its complex physical space and abundant biological resources can provide spawning grounds, breeding grounds, feeding grounds, and habitats for marine animals, as well as food for dugongs, swans, and other species, and have important resource conservation functions. However, seagrass beds belong to fragile ecosystems and are facing severe degradation trends globally due to natural environmental changes and human activities. Research has shown that since 1990, seagrass beds worldwide have rapidly degraded at a rate of 7% per year. To restore the 'underwater grassland', it is urgent to strengthen protection, such as establishing protected areas; Ecological restoration, also known as' planting grass on the seabed ', needs to be carried out. Similar to rice cultivation, "underwater grass planting" typically involves processes such as environmental remediation, sowing, seedling cultivation, and transplanting. In recent years, the ecological restoration technology of seagrass beds in China has developed rapidly, with the emergence of seagrass seed sowing methods such as bagging, gauze wrapping, and mud block wrapping, as well as plant transplantation methods such as hemp rope seedling clamping and substrate fixation, greatly improving the efficiency and effectiveness of seagrass bed ecological restoration. After years of dedicated research, we have made some breakthroughs in the theory and technology of ecological restoration of temperate seagrass beds, established a relatively complete technical system, and promoted the large-scale development of seagrass bed ecological restoration projects in China. As of now, we have restored and maintained over 20000 acres of "underwater grasslands" in offshore areas such as Xiaoyao Lake and Swan Lake in Weihai, Shandong, Zhaoyuan and Changdao in Yantai, Kendong in Dongying, and Caofeidian in Tangshan, Hebei. In the future, we will continue to dive underwater and plant even more vast 'underwater grasslands'. (New Society)