MARRES, the continuation of the SPHERE project, aims to put in focus Rogoznica lake as an unique example of the threatened marine ecosystems, which feels hydrographic and atmospheric conditions of the Adriatic Sea. Rogoznica lake will be a model for monitoring and characterization of biogeochemical processes related to sulfur and carbon cycling at different redox boundaries under different environmental conditions. The project will achieve scientific mission by state-of-the art laboratory studies and field monitoring integrated in an unique biogeochemical research. Discussion and synthesis of new and long term data of the Lake’s ecological status is fundamental for development of biogeochemical model. An important part of the project will be focused on the exchange and transport between atmosphere, water column and sediment by measuring the atmospheric input (wet deposition) of sulfur compounds (organic and inorganic), organic carbon, radionuclides (Be-7, Pb-210), nutrients and trace metals. Additionally, the ecology of the microorganisms, phyto- and zoo-plankton, bentos will be correlated with specific lake water physico-chemical conditions. The northern Adriatic as a semi closed, shallow and potentially eutrophic marine basin with occasional appearance of bottom anoxia will be used as another system for tracking environmental changes related to eutrophication. The MARRES is planned for the period of 4 years, and its result will contribute substantially to the improvement of the knowledge on the studied ecosystems responses to likely changes of physical, chemical and biological conditions affected by natural and anthropogenic i.e. global environmental change. Research objectives listed above, especially those related to mobilization of human, technical, and infrastructural capacities of the RBI and involved partner Institutions are closely in line with strategic priorities and promotion of Croatian science, knowledge and experience on the world science market.