engleski

Bacterial abundance and production in oligotrophic south Adriatic waters: relation to plankton food web structure

The bacterial abundance and production were investigated according to hydrographic regime and plankton vertical distribution during Medusa 1 (CREICO) cruise in the middle and southern Adriatic in spring 2002. At most stations we observed termocline at the depth of approx. 20m and a prominent fluorescence peak at about 70m. Phytoplankton taxonomic composition was assessed in terms of chemotaxonomic pigments and microzooplankton and net zooplankton were grouped according to their trophic role into pico-, nano-, micro- and omniphageus. The bacterial abundance and production showed values typical for oligotrophic water, with the range from 6.5 x 104 cells/l to 4.3 x 105 cells/l, and the total community incorporation rates of tritiated leucine ([3H]-Leu) from 0.01 mg C/l/hour to 0.39 mgC/l/hour. Phytoplankton was dominated by 19’ ; -hexanoyloxyfucoxanthin – ; containing phytoplankton (prymnesiopytes). Higher bacterial production was associated with increased abundance of pico- and nanophageus zooplankton.

ecology; oligotrophic water; food web

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