engleski

Periphyton pigments and diatom community composition in the Zrmanja Estuary (Eastern Adriatic)

We defined slow colonisation of periphyton community on Plexiglas plates in the surface, brackish layer of the small, oligotrophic, karstic estuary (Zrmanja, eastern Adriatic coast) during the summer 2000. The 28 days colonisation process was measured every three days. High-performance liquid chromatography (HPLC) was used to quantify contribution of different algae in periphytic community. Abundance and taxonomical composition of diatoms were determined using inverted microscope (magnification of 400x and 1000x) (Utermöhl 1958). Colonisation could be differentiated in three phases: lag phase (lasted 13 days), growth phase (13-25 days) and decline phase (after 25 days). Maximum periphyton biomass was detected during 19-25 days of colonisation, with concentration of chlorophyll a of 1630-1674 ng cm-2. Chemotaxonomic characterization of periphyton community provided diatoms as dominant group (maximum concentration of fucoxanthin 1371 ng cm-2). Maximum abundance of diatoms (1.8 x 107 cells cm-2) was determined after 25 days of colonisation. Low concentrations of zeaxanthin, lutein and chlorophyll b (maximum concentration < 28 ng cm-2) indicated small contribution of cyanobacteria and green algae in the periphyton community.

Periphytic diatoms; colonisation; pigments; Zrmanja Estuary; Adriatic Sea

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