The researchers collected data on phytoplankton in Korean coastal waters to understand their ecology. They found that the number of phytoplankton individuals and the amount of chlorophyll were more closely related than the size of the phytoplankton and the chlorophyll amount. This means that smaller phytoplankton have more chlorophyll compared to their size than larger phytoplankton. Therefore, using the number of phytoplankton individuals is a better way to understand their ecology in Korean coastal waters.