Posters

Poster Session 1, Monday,  October  3, 15:40–18:00

Poster 61

Island-Trapped Waves (ITWs) effect on plankton primary producers in a Mediterranean hot spot area

Global niche models have predicted a global increase of picocyanobacteria abundances and contribution to primary production, due to temperature rise and enhanced stratification, potentially leading to complex changes in oceanic microbial communities. Here, we report data from island-trapped waves (ITWs) phenomena observed off the Lastovo island (Adriatic Sea), and the related daily thermocline oscillations which may have significant impact on nutrient and phytoplankton transports into the euphotic zone. Due to the nonlinear response of production to light and the strong decay of the light intensity with depth, the combined response of primary production to ITWs is expected to be significant. Since the waves are trapped around the island, at one location on the island perimeter the ITWs is bound to be in phase with the diurnal cycle of irradiance. Because of the mentioned nonlinearities, we expect an overall increase of productivity around the island. During the stratification period in 2021 a set of thermistors was deployed up to 45 m depth at opposite sides of Lastovo island. Bottom-moored ADCP recorded currents every 4 m between 11 and 83 m. Several episodes with large diurnal thermocline oscillations up to 30 m were observed. Deep chlorophyll maxima, dominated by diatoms and Prochloroccocus, were observed in the 40–60 m depth layer and were lagging behind the thermocline oscillations. A microzooplankton and phytoplankton a community shift was observed with time, co-occurring with nutrient dynamics. Cyanobacteria did not follow the observed temporal trend of larger phytoplankton, but have displayed a strong spatial distribution pattern. 

Zrinka Ljubešić, University of Zagreb, [email protected], 0000-0001-5502-3662 

Žarko Kovač, University of Split Faculty of Science, Croatia, [email protected] 

Hrvoje Mihanović, Institute of Oceanography and Fisheries, Croatia, [email protected] 

Mirko Orlić, University of Zagreb Faculty of Science, Department of Geophysics, Croatia, [email protected]

Raffaella Casotti, Stazione Zoologica Anton Dohnr, Naples, Italy, [email protected] 

Anna Chiara Trano, Stazione Zoologica Anton Dohnr, Naples, Italy, [email protected] 

Eric Achterberg, GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, [email protected] 

Davor Lučić, University of Dubrovnik, Institute for Marine and Coastal Research, Croatia, [email protected] 

Branka Pestorić, Institute of Marine Biology, Kotor, Monte Negro, [email protected] 

Melissa Omand, University of Rhode Island, Graduate School of Oceanography, USA, [email protected] 

Ivona Cetinić, Ocean Ecology Laboratory at NASA/Goddard Space Flight Center, Greenbelt, Maryland, USA, [email protected] 

Luka Kovačić, University of Split Faculty of Science, Croatia, [email protected] 

Antonija Matek, University of Zagreb Faculty of Science, Department of Biology, Croatia, [email protected] 

Hrvoje Čižmek, Marine Explorers Society 20.000 leagues, Croatia, [email protected] 

Barbara Čolić, Marine Explorers Society 20.000 leagues, Croatia, [email protected] 

Damir Viličić, University of Zagreb Faculty of Science, Department of Biology, Croatia, [email protected]