Harmful blooms of Cochlodinium geminatum have been occurring in the Pearl River Estuary, South China since 2006. A recent study looked at the environmental factors and phytoplankton changes during and after a bloom in 2018. They found that water temperature and salinity played a big role in the bloom. The phytoplankton community shifted during the bloom, with fewer dominant species. After the bloom, diatoms increased in number and diversity. The researchers also found retinal, a teratogenic agent, in the field samples and C. geminatum. This suggests that retinal can accumulate during a bloom and pose a risk to aquatic organisms. This study gives us more insight into the ecological impacts of C. geminatum blooms.