engleski

Epiphytic diatom assemblages on invasive algae Caulerpa taxifolia and autochtonous Halimeda tuna and Padina sp. from the Adriatic Sea– summer/autumn aspect

This study focuses on the taxonomy of the epiphytic diatoms in the area of the invasive macroalgae of the genus Caulerpa. Caulerpa species are characterized by the presence of secondary metabolites, such as caulerpenyne (CYN), the main function of which is a chemical defense mechanism against herbivores and epiphytes. Epiphytic diatoms were studied on fronds of Caulepa taxifolia (“killer seaweed”) and, for comparison, on autochthonous macroalgae Padina sp. and Halimeda tuna at eastern Adriatic Sea coast (Island of Hvar) in the summer and autumn of 2010. Light and scanning electron microscopy examinations were used for qualitative analysis. The wide (3.11– 4.88) range of Shannon-Wiener Diversity Index was found on Caulerpa taxifolia, with maximum in August and minimum in October. While the number of taxa on Caulerpa taxifolia fronds increased from June (41) to August (88), in autumn taxa richness of Caulerpa taxifolia decline due to high relative abundance of Cocconeis caulerpacola which is a diatom typical for Caulerpa. On the contrary, the highest numbers of taxa on Padina sp. was observed in September (82). For the first time the detailed composition of epiphytic diatoms and seasonal dynamics in area affected by invasive macroalga Caulerpa taxifolia were determined.

macroalgae ; epibiotic ; Cocconeis ; Mastogloia ; Mediterrranean ; diatom community ; succession

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