engleski

First record of aerobic anoxygenic phototrophs in the Eastern Adriatic Sea

The presence and spatial patterns of aerobic anoxygenic phototrophs were investigated, for the first time, in the Adriatic Sea. Also, the spatial patterns of the whole picoplankton community as well as the environmental factors that potentially influence these patterns were highlighted. Aerobic anoxygenic phototrophs abundances ranged from 10 x103 to 240 x 103 cells mL-1 and their proportion in total bacteria abundances ranged from 2.49 to 19.89%. These values are in the upper range of aerobic anoxygenic phototrophs abundances observed in marine environments. Aerobic anoxygenic phototrophs seem to be more abundant in mesotrophic coastal and estuarine waters than in the oligotrophic open sea implying their clear preference for higher trophic environments. Multivariate analyses proved that environmental factors influenced the picoplankton community interdependently. Chlorophyll a was the main driving factor for the picoplankton community, accounting for 33.3% of picoplankton community variance, followed by NO2 (17.9% of variance explained) and temperature (14.2% of variance explained). Chlorophyll a showed stronger correlation with aerobic anoxygenic phototrophs, non-pigmented bacteria and picoeukaryotes than with cyanobacteria. Abundance of cyanobacteria was more correlated to salinity and the N:P ratio than to nutrient concentrations.

aerobic anoxygenic phototrophs ; Adriatic Sea ; picoplankton community

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