A PHYTOPLANKTON TIME SERIES IN THE NORTHWESTERN ADRIATIC SEA: STRUCTURE AND DYNAMICS OF THE ASSEMBLAGES IN A COASTAL ECOSYSTEM

STUDIO DELLE SERIE TEMPORALI DEL FITOPLANCTON IN MAR ADRIATICO NORDOCCIDENTALE: STRUTTURA E DINAMICA DEI POPOLAMENTI IN UN ECOSISTEMA COSTIERO

Abstract

Phytoplankton is responsible for nearly half of the photosynthetic fixation of CO₂ and represents the first level of the food web in oceans. Due to phytoplankton fundamental ecological role, the aim of this study was to assess whether the phytoplankton assemblage structure could vary in time and space and if this variation could be due to such environmental forcing. Surface seawater samples were collected monthly from 2008 to 2019 at two coastal sites in the Northwestern Adriatic Sea together with physico-chemical and biological parameters recorded by a multiparametric probe. Phytoplankton identification and quantification were performed togethet with chlorophyll a and dissolved inorganic nutrient concentrations determination. Data analysis indicated that Skeletonema marinoi (Sarno and Zingone, 2005), Thalassionema nitzschioides (Mereschkowsky, 1902), Dactyliosolen fragilissimus (Hasle, 1996), and undetermined Dinophyceae, showed a non-random pattern in the binary time series. Moreover, the observed phytoplankton assemblage structure was driven by seasonal and environmental factors.