Ecology of picocyanobacteria

 

Picocyanobacteria are the main components of autotrophic picoplankton (size range 0.2-2 um); they are distributed worldwide in oceans and lakes of different trophic state. They are of great importance in the carbon flow of aquatic environments as they can fix up to 70% of the inorganic carbon. Two main genera, Synechococcus and Cyanobium, dominate in freshwaters.
We have been studying their ecology since ’90 in lakes in Europe, Mexico, Argentina (North Patagonia) and recently in the Black Sea thanks to international cooperation with Universities and Research Institutes. The book chapter by Springer in 2012, summarizes many of the results of our research on the ecology of picocyanobacteria. There you can find information on their dynamics in lakes along a trophic gradient, as well as the effect of chemical, physical and biological drivers on their activity. In the mini review published in 2017 there are some updated data on picocyanobacteria.

At present we mainly focus on Synechococcus strain isolation, sequencing, phylogeny, and microcolony formation. In our Institute we have a monoclonal strain collection of phycoetrythrin and phycocyanin Synechococcus from different lakes and from the Black Sea. We isolated Synechococcus from the deep anoxic Black Sea (BS55D and BS56D) able to survive in harsh conditions and to accumulate Chlorophyll in the dark. We studied microcolony formation mechanisms at gene level and the interaction Synechococcus-associated bacteria. We are focussing on functional genes that can be active and could be the secret for the adaptability of Synechococcus along its evolutionary history.