One of the United Nations Sustainable Development Goals -- "Life Below Water," is of particular importance to Japan. This episode introduces Japanese companies that are taking action to help counter the effects of seafloor desertification by helping to bring kelp forests back to coastal seabeds. A young startup has come up with a clever way to slow the spread of kelp-eating sea urchins and provide additional economic benefits to local communities by collecting, fattening up and selling the prickly pests. Elsewhere, a major steel maker is producing a special fertilizer made from a mixture of steel slag and other organic compounds that is promoting the regrowth of marine plant life off of Japan's coastal waters.