Seaweed has high industrial, agricultural, edible and medicinal value. Macroalgae is a very important industrial raw material. It can not only be extracted from it or used to make a variety of industrial products such as iodine, potassium, algin, mannitol, methane, ethanol, light oil, lubricating oil, paraffin, rubber, plastics, etc., but also Can be used as a new bioenergy source. American marine scientists once established an underwater planting field about 100 kilometers away from the Pacific coast city of San Diego, and artificially transplanted a giant brown algae in 12 meters of sea water. This seaweed can grow up to 60 centimeters a day and is rich in organic matter. These organic substances can be easily turned into flammable gas - methane with the help of bacteria, and they can also be turned into "petroleum-like" products by simple heating. According to calculations by relevant experts, an underwater plantation with an area of ??4,108 square meters can provide all the oil for a small city with a population of 50,000. A large seaweed farm stretching 750 kilometers would provide enough methane to replace all the natural gas currently used in the United States. Currently, the U.S. Department of Energy and the Solar Energy Research Institute are expanding experiments to inject seawater into pools to cultivate this single-cell algae to directly refine gasoline and diesel for automobiles.