The researchers studied the changes in the marine environment and phytoplankton community in the southern part of Yeosu, South Korea, over four seasons. They found that water temperature was higher in Gamak Bay in summer and spring, while it was higher in Yeosuhae Bay in autumn and winter. Salinity levels were mostly consistent, except near a sewage outlet. Phytoplankton species varied throughout the year, with centric diatoms dominating. Dominant species changed with the seasons, with higher phytoplankton levels in Gamak Bay in summer. The study also identified different regions based on marine conditions and phytoplankton communities.