An agricultural revolution at sea
Before the 1950s, China’s supply of kelp, a large brown seaweed, depended entirely on wild harvesting. The primary species, Laminaria japonica, was introduced from Japan in the late 1920s but could only grow naturally in a few cold-water areas. This scarcity had significant consequences for a population where iodine deficiency was a widespread health issue. Kelp is a rich source of iodine, and its limited availability restricted a dietary tool for preventing goiter and other related conditions. The total annual production of kelp hovered around 60 metric tons, a tiny amount for a large nation.
The Qingdao Marine Biology Laboratory, founded in 1950 and later expanded into the Institute of Oceanology, Chinese Academy of Sciences (IOCAS), addressed this problem. Led by the pioneering phycologist C.K. Tseng (Zeng Chengkui), often called the "Father of Chinese Oceanography," researchers at the station began the difficult process of domesticating a wild sea plant. Tseng and his team developed three foundational techniques. First was the floating raft method, a new form of aquaculture where kelp is attached to ropes suspended from rafts, allowing it to grow at optimal depths regardless of tides. Second, they created a system for cultivating sporelings indoors in cooled water (below 10°C) during the hot summer months when the kelp could not survive in the open sea. Finally, they devised methods for applying fertilizer directly to the raft farms in the nutrient-variable open ocean.