engleski

The influence of organic matter and phytoplankton pigments on the distribution of bacteria in sediments of Kaštela Bay (Adriatic Sea)

Bacterial abundance, biomass, volume and morphological diversity were studied in sediments collected in the Eastern Adriatic Sea (Kaštela Bay) in order to investigate their relations with the changes of different environmental parameters. For assessing the changes of investigated parameters on temporal scale and between sediment layers, the sediment samples were collected monthly during 2002 with a piston corer from the sediment surface to the depth of 10 cm. The concentrations of organic matter (OM), chloroplastic pigment equivalents (CPE), chlorophyll a (chl a) and phaeopigments (PHAEO) were used as indicators of substrate concentrations in sediments. Sediment depth was a significant factor influencing the distribution of bacterial abundance, biomass and volume. Granulometric properties of the sediment had no effect on the distribution of bacteria. Bacterial abundance, biomass and volume were strongly related to the indicators of substrate concentrations on both scales. The accumulation of labile OM in deeper layers also had a profound effect on the size and structure of bacteria. High amounts of OM and the low proportion of labile organic fraction (CPE ; chl a and PHAEO) indicate that this environment acts as a sink for accumulation of detrital material.

Benthos; bacterial biomass; cell volume; chlorophyll a; phaeopigments

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