The governments of the Federal Republic of Germany and the Kingdom of Denmark have decided in September 2008 to realize a crossing of the Fehmarn Belt in form of a bridge or a tunnel between Germany and Denmark until 2018. The IOW is involved with studies on the ecological impact on the Baltic Sea. The implementation of simulation calculations with a circulation and Ecosystem model of the Baltic Sea takes place on the high performance computing system HLRN-II. The ZIB represents his knowledge of modern methods of calculation and on the effective use of the Supercomputer available.