The density of the radioactive material that leaked into the ocean off Fukushima prefecture following the Fukushima Daiichi nuclear power plant accident in March of 2011 diminished as it was diffused by ocean currents, but also followed a transition process unique to radioactive materials, including decay and sedimentation. Even with the current reduced amount of leakage, conditions of the ocean water and seabed have not returned to those from before the accident. This article examines the mid-to-long range accumulation of radioactive materials and their transition mechanism based on an assessment perspective.

The ocean areas around the maritime state of Japan are important for providing a variety of resources but are also the focus of conservation and protection efforts. One approach to understanding and using the marine environment is marine biology research. This article gives an overview of research into microbiology, those life forms too small to be seen with the naked eye but which play important roles in marine ecosystems.

A joint research project for protection of the Chinese sturgeon was undertaken between Japan and China from 2005 to 2007, making use of the world's most advanced biologging methodology. Environmental conditions along the Yangtze have worsened with construction of the Three Gorges Dam however, necessitating appropriate and immediate countermeasures. Conservation of new spawning areas, avoidance of collision with boat traffic, and management of silt accumulation at the dam are identified as necessary measures for protection of the species.