This thesis has two focus points in the framework of boron in marine biogenic calcium carbonates and its potential as a proxy. Focus point one deals with potential factors, which might influence the boron isotopic composition and boron concentration in marine biogenic calcium carbonates. Since boron in marine biogenic calcium carbonates serves as a proxy for the reconstruction of the carbonate system, the awareness and characterization of potential impacts is of great importance. For that purpose investigations on 1) the effects of temperature and growth rate on the boron concentration and isotopic composition in calcium carbonate were investigated and 2) the potential carbonate system parameters controlling boron incorporation into shells of foraminifers have been determined. The second focus point introduces a new analytical technique which for the first time allows to determine the boron isotopic composition and boron concentration simultaneously in marine biogenic calcium carbonates. This is a great opportunity for applications in the field of paleoceanography and paleoclimatology since the determination of the boron isotopic composition and boron concentration provides two parameters of the carbonate system which are at least required to reconstruct it.