The researchers studied the types of small sea creatures living on the ocean floor in the southern coast of the East Sea, Korea. They collected samples over a few years and found 76 different species, including some that are at risk of disappearing. The number of species and how many of each were found changed depending on the season. More species were seen in spring and summer, while fewer were found in autumn and winter. Overall, there were fewer types of creatures in the summer compared to other seasons.