Inorganic nutrients and dissolved organic matter are known to structure the functioning and the productivity of the marine ecosystems. Coastal areas of the Baltic Sea are especially affected by large riverine discharge. It is well known that riverborne nutrients comprise the largest fraction of nutrient inputs into the Baltic Sea. Less attention has been paid to the effect of the river loads in landfast ice-covered regions, such as a large part of the Baltic coasts. Also ship emissions are a major contributing factor to the atmospheric deposition in some areas and seasons and are another important source of inorganic nutrients and contaminants to the Baltic Sea. The Baltic Sea has some of the busiest shipping routes in the world. Current practices include extensive emissions of nitrogen oxides (NOsubX), sulphur oxides and particulate matter. In particular, NOsubX emissions from ships cause acid depositions that can be detrimental to the natural environment and also contribute to eutrophication. To date, no modelling studies exist on theses fundamental and peculiar traits of the Baltic Sea. Moreover, the Baltic Sea presents several peculiarities in comparison with many coastal seas and requires a complex and comprehensive ecosystem model, which may consider, for instance, diazotrophic cyanobacteria and spring-blooming dinoflagelattes as those are important relative contributors to the whole biomass and/or are also of concern for their toxic potential. This poster aims to present the modelling approach and the scientific methods that will be used to study the role and relative contribution of river nutrient loads vs atmospheric deposition to the state of the Baltic Sea ecosystem in the framework of a new 3 year project, recently funded by the Maj and Tor Nessling Foundation. The project aims to develop a comprehensive ecosystem model for the Baltic Sea, which will embed both sea-ice and oceanic systems. Model results will be compared with several datasets available at the Finnish Environment Institute and at the Finnish Meteorological Institute. The ultimate goal is a more complete understanding of the behavior of anthropogenic nutrient loads in the Baltic ecosystem in the coming decades. Final results will be able to provide national and international authorities with new instruments able to support new political decisions in terms of environmental protection of the Baltic Sea and assist the unavoidable implementation of climate change adaptation plans.