The world’s largest circulation, reaching into the ocean’s depths, is due to the density gradient between dense water sinking and then gradually rising to the surface. Dense water is produced when large amounts of sea ice forms in the Southern Ocean and the Sea of Okhotsk, setting off the Thermohaline Circulation. Using satellite data, we are now able to estimate sea ice production, allowing us to identify the formation area and variability of dense water. We have also revealed that production of sinking dense water is gradually decreasing due to recent global warming.

In Japan, the world’s most volcanic country, there is a one percent probability of a super eruption over the next 100 years, with the possibility of catastrophic disaster. In order to predict such an eruption, precise imaging and monitoring of the massive underground magma reservoir is necessary. However, in practical terms, the carrying out of man-made earthquake probes for this purpose is almost impossible on land. We have therefore decided to target the Kikai Caldera, the one giant submarine volcano in Japan, which underwent a supereruption of 7.3 ka.

Little progress is being made towards solving the problem of ocean debris, as there is currently no public organ for its collection, and its accumulation on the sea floor is out of sight. The Geography/History club at Sanyo Girls Junior and Senior High Schools is carrying out cleanup activities of debris on the floor of the Seto Inland Sea and drift debris in island areas as well as educational outreach activities. Given the extremely low level of awareness of this problem, we want to work towards its solution through dissemination of information and local collaboration.