Relationships between bacteria and phytoplankton in the Mar Piccolo of Taranto (Ionian Sea) in two years of sampling ( 2006- 2008).

In aquatic ecosystems, phytoplanktonic organisms are the major primary producers and bacteria the major decomposers. The interactions between phytoplankton and bacteria may be dependent on nutrient resources. Anthropogenic inputs, by modifying nutrient status of sea, might induce changes in these interactions and thus, could have many consequences on some ecological processes such as primary production or importance of microbial recycling activity. To verify this hypothesis, we have continued our studies on the interactions of bacteria and phytoplankton in the Mar Piccolo of Taranto (Ionian Sea). Particularly, the aims of this work were to analyse the qualitative and quantitative composition of heterotrophic bacteria and phytoplankton communities and the interactions between these two planktonic components. Data of the second year confirm the results of the former year in the sense that in both years phytoplanktonic blooms anticipate the bacterial ones suggesting that phytoplanktonic blooms could be probably responsible for the availability of organic matter for bacterial populations.