Projets terminés

Metal Bioavailability to aquatic photosynthetic organisms in Changing Environment (BioChEn)

The interactions of climate variability and the changes in the surface radiation are anticipated to affect the aquatic biogeochemical cycles and thus to increase the uncertainty in predicting environmental risks associated with chemical pollution. Therefore, the understanding of the underlying mechanisms that govern the contaminant (e.g. toxic metal) interactions with different biotic and abiotic components in a changing environment is of crucial importance for the development of predictive models for environmental risk assessment and sustainable water quality in the 21st century.

The present project, supported by the Swiss National Science Foundation, focuses on the metal bioavailability as a mechanistic concept allowing to quantitatively link the physical and chemical processes in the medium surrounding biota to the induced biological effects. A unique array of novel and powerful technologies will be used to determine how the interacting effects of toxic metals, increased solar radiation and dissolved organic matter (DOM) alterations will impact the photosynthetic organisms in surface waters.

Photosynthetic organisms are major players in the surface water primary productivity and represent the basis of the aquatic food chain. The following key questions will be addressed: (i) To what extent does increased solar radiation affect the kinetics and size speciation of metal - DOM complexes of red-ox sensitive and insensitive metals?; (ii) How does the combination of enhanced solar radiation and DOM - alteration affect metal bioavailability?; (iii) What are the consequences for photosynthetic organisms in surface waters? Laboratory work investigating the impact of solar radiation on metal bioavailability and effects on phytoplankton and macrophytes will provide useful insights at a mechanistic level; the proposed small scale simulations in a microcosm will increase our understanding of complex parameters controlling bioavailability and its effect on photosynthetic freshwater organisms. The project aims at filling the existing knowledge gaps and reducing uncertainties, concerning the combined action of chemical and other environmental stressors on two major groups of aquatic primary producers.

Contact: Giulia Cheloni, Dr Claudia Cosio and Prof. Vera Slaveykova