engleski

Phytoplankton abundance and composition in the oligotrophic, phosphate limited NE coastal Adriatic Sea

The research has been performed in the NE coastal Adriatic Sea (Rijeka Bay and Vinodol Channel), during 2002 - 2005. The area is strongly influenced by the karstic hydrology and catabaric wind (bora) from Dinaric Alps, and relatively isolated by islands extending parallel to the coast. Proliferation of diatoms (microphytoplankton) appears in spring, a period enriched with nutrients. Nanoplankton containing Cryptophytes, dinoflagellates, coccolithophorids and green algae dominated during oligotrophic summer. Development of phytoplankton was mainly detected in the surface layer (0– 10 m). The appearance of cryptophytes was positively and significantly correlated with dinoflagellates, indicating their metabolic mutualism (mixotrophic potential) in the oligotrophic conditions. Low summer concentration of orthophosphates and total inorganic nitrogen (frequently less than 0.01, and 0.1 µ ; ; mol L-1, as well as low abundance of diatoms (less than 5 x 10^5 cells L-1) and dinoflagellates (less than 5x10^3 cells L-1), indicated oligotrophic conditions in this specific coastal environment.

Phytoplankton; limiting nutrients; seasonality; Adriatic Sea

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