AME 15:255-264 (1998)  -  doi:10.3354/ame015255

Quantitative relationships between phytoplankton, bacteria and protists in an Aegean semi-enclosed embayment (Maliakos Gulf, Greece)

Konstantinos Ar. Kormas*, Konstantinos Kapiris, Maria Thessalou-Legaki, Artemis Nicolaidou

Department of Zoology & Marine Biology, School of Biology, University of Athens, GR-157 84 Panepistimiopoli, Athens, Greece

ABSTRACT: The seasonal variations of temperature, dissolved organic carbon (DOC), chlorophyll a (chl a), and bacterial and protistan abundance were investigated in an enclosed Eastern Mediterranean embayment over an 8 mo period. DOC levels in the gulf were high, likely due to allochthonous input through freshwater discharge. However, after the end of spring, when allochthonous input was minimal, bacterial abundance was linearly related to chl a and DOC, suggesting that during this period the remaining DOC pool (probably autochthonous DOC) was important. Bacterial abundance was significantly correlated with the biomass of the phytoplankton at the end of spring and throughout summer. A correspondence of protistan abundance with bacteria, especially during the warm months, when the phytoplankton biomass was low, suggests that the microbial loop is the dominant component of the food web structure during the oligotrophic period of the year.

KEY WORDS: Phytoplankton · Bacteria · Protists · Microbial loop · Coastal waters · Mediterranean

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