engleski

Different intensity of TEP formation along the trophic gradient in the northern Adriatic

Alochthonous Po River discharge into the northern Adriatic ecosystem has major influence on its functioning, since this river has high flow rates and flows through the most intensive agricultural and industrial Italian regions. Not only primary production is strongly affected by Po River inputs, but also polysaccharidic particles (TEP, transparent exopolymer particles) which are mostly result of aggregation of excreted microorganisms’ polysaccharides. Abundant and sticky TEP as a step in organic matter aggregation are hypothesized to have important role as precursors in northern Adriatic mucilages’ appearances, especially knowing that peak values in spring and summer reported herein are among the highest measured in oceans. Our results clearly indicate the gradual west-east gradient, from the highest values toward the lower ones. Significantly positive correlations between TEP and autotrophic biomass (chlorophyll a) were observed, confirming TEP dependence on phytoplankton, specially at the most western stations. At the same time the correlations with salinity were often significantly negative, indicating the importance of the freshened water influenced by Po River for TEP formation. In conclusion, increased TEP formation, as a phase in organic matter aggregation processes, is in the northern Adriatic considerably supported by alochthonous Po River inputs.

TEP; Northern Adriatic; Trophic gradient

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