engleski

Seasonal cycle of transparent exopolymer particles' formation in the northern Adriatic during years with (2000) and without mucilage events (1999)

Transparent exopolymer particles' (TEP) concentrations were measured approximately monthly in 1999 (year without mucilage events) and 2000 (with a late spring event) along an eutrophication gradient between the Po River delta (NE Italy) and Rovinj (Istria, Croatia). The highest TEP concentrations (up to 2600 &micro ; g equiv. L-1) and significant correlations with chlorophyll a concentrations, salinity, bacterial abundance and secondary production were observed in the upper water column (0-10 m), while in the deeper water column the TEP concentrations were significantly lower (<500 &micro ; g equiv.L-1), without seasonal pattern. In the period February-August, when TEP formation is the most intensive, analyzed correlations were more often significant in 1999, but TEP high values were more frequent in 2000. In contrast, in the period September-December of 2000, when the Po nutrient contributions were exceptionally high, TEP values were lower than in the same period of 1999. In both years phytoplankton spring blooms in the western coastal area represented an important factor of TEP formation. A part of produced TEP was then transported by transversal currents eastwards, accumulating in the physical fronts of the eastern basin.

TEP; Chlorophyll a; Salinity; Bacteria; Northern Adriatic

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