engleski

Seasonal switching between relative importance of bottom-up and top-down control of bacterial and heterotrophic nanoflagellate abundance

Seasonal dynamics of bacterial and heterotrophic nanoflagellate (HNF) species assemblages were analysed in Kaštela Bay (middle Adriatic Sea). Dominant patterns identified were: (1) during summer and autumn bacterial abundance was mainly controlled by HNF grazing (top-down), whereas HNF abundance was controlled by bacterial abundance (bottom-up); (2) during winter and spring the coupling between bacteria and HNF was very weak, and bacterial abundance was mainly controlled by zooplankton grazimg (top-down); (3) throughout the year, both bacterial and HNF species assemblages alternated with two periods of stable abundance, first with high and second with low values; (4) top-down effect was dominant in bacterial switching from stable abundance with high values to stable abundance with low values, whereas bottom-up model dominated in inverese process; and vice versa for HNF.

Bottom-up; Top-down; Bacteria; Heterotrophic nanoflagellates; Adriatic Sea

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