Since childhood, Koreans have often heard that "our country is surrounded by the sea on three sides, and the sea is the resource of the future." However, the times we live in now are witnessing rapid changes due to factors like population growth and industrialization. The oceans, being one of the last resource frontiers, are now facing multiple threats that could make them our final refuge.

Unfortunately, our understanding of the current state of these crucial waters is limited. In recent years, the oceans have been subjected to various perils, including warming caused by increased carbon dioxide in the atmosphere, ocean acidification, oxygen depletion, pollution, invasive species, red tides, blooms, coral bleaching, and overfishing. In this course, we will examine these issues, exploring their root causes and examining how they impact marine ecosystems and human life.