The researchers studied the bacteria in Gwangyang Bay seawater throughout the seasons. They used two methods to analyze the bacterial community: isolating bacteria in a lab and directly studying DNA from the water. They found that different types of bacteria were more common in different seasons. In the spring, Firmicutes bacteria were dominant, while Proteobacteria were dominant in other seasons. The diversity of bacteria was highest in the fall. Overall, the bacterial community in the seawater changed seasonally, with similar patterns seen using both methods.