engleski

Epiphytic diatoms on Posidonia oceanica (L.) Delile leaves from eastern Adriatic Sea

This research provides a description of the epiphytic diatom community living on the blades of the marine seagrass Posidonia oceanica in the coastal area of the eastern Adriatic Sea. Samples were collected in May 2017, from a meadow located in Tetevišćica Bay, on the western side of Dugi otok island (43° 58' 22'' N ; 15° 03' 36'' E) at three depths: 10, 15 and 20 m. Each blade sample was divided into three segments along the leaf axis (basal meristemal, middle and apical) to explore the possible community zonation pattern. Twenty-one samples were analyzed by light microscope and the epiphytic diatom community structure was determined. A total of 68 taxa belonging to 30 genera were found: 43 from 10 m depth, 41 from 15 m depth and 39 from 20 m depth. All identified species are commonly recorded from other marine benthic periphytic and epiphytic habitats. The genus Cocconeis was dominant in all samples, which is typical for epiphytic biofouling of P. oceanica leaves. Although no changes in the community structure related to the position on P. oceanica blade were observed, ANOSIM tests (p<0.05) performed on species' relative abundances confirmed that the diatom communities differed significantly according to their depths. This study contributed to the knowledge on biodiversity associated with Adriatic P. oceanica meadows, which are threatened by human activities and invasive species. Additionally, this research provided important information on the identification of the taxa-specific epiphytic diatom community on seagrasses in the eastern Adriatic Sea.

Bacillariophyta ; Neptune grass ; Mediterranean Sea ; Cocconeis ; species identification ; light microscopy

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