Imperative of TRANSFORMER was to provide understanding and gain practical knowledge on behaviour of emerging contaminants under multiple stress conditions. Likewise, project aimed in providing an integrated view of molecular events in general response of a biofilm to stress and multi-stress events. These issues, being addressed by TRANSFORMER are very important from two perspectives. One is understanding and gaining practical knowledge on the additive effects of multiple stressors because current and future rates of ecosystem response predicted on the basis of individual stressor effects may be underestimated. And the other is studying community global patterns of metabolic activity and response to stress and multi stress perturbations in order to comprehend systems-level behaviour. In summary, TRANSFORMER showed that multi-stress (i.e. flow intermittency and emerging contaminants exposure) conditions enhance biofilm biodegradation ability during short and medium term exposure suggesting indirect antagonistic relationship between drought and emerging contaminants that change water chemical status. Observed effects may suggest that, on a contrary to current believes, the short and medium term ECs biodegradation efficiency in intermittent systems may be higher. Exo-metabolome profiling demonstrates that different perturbations are immediately reflected on biofilm released metabolites. In comparison with classical biofilm descriptors the exo-metabolite response is more specific and significantly faster. Observed dissimilarity, comparing to control samples, is highest for multi-stress perturbation suggesting uppermost disturbance in molecular output for multi-stress samples.
