Impact of the Winter Convective Event on Gelatinous Zooplankton in the Open Southern Adriatic

The southern Adriatic is the deepest part of the Adriatic Sea (1242 m) and one of three sites of open-sea deep convection in the Mediterranean. By analyzing zooplankton samples taken in the open southern Adriatic in winter and spring/summer 2021 we investigated effect of winter vertical mixing on distribution of gelatinous zooplankton. During the convection time in winter, gelatinous zooplankton abundance was low and unusual vertical distribution for some species was occurred. In the spring-summer time an increase in gelatinous zooplankton abundance in upper and deeper layer was registered. This is probably related to the early spring phytoplankton bloom enhanced by nutrient input into euphotic zone due to winter mixing phase. As a consequence of this event, there is also availability of more food for deep-sea gelatinous organisms.