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Abstract

We investigated the molecular composition of dissolved organic matter (DOM) from 15 various rivers, bogs and soil sites to test for their ecosystems unique molecular patterns. 16 This information is prerequisite for searching of new marker compounds that might help 17 tracing the fate of ecosystem-derived organic matter from terrestrial to marine systems. 18 We used electrospray ionization Fourier transform ion cyclotron resonance mass 19 spectrometry (ESI-FT-ICR-MS) to identify the ecosystem-specific molecular DOM 20 characteristics. We investigated 39 samples and explored their patterns through non21 metric multidimensional scaling (NMDS). Based on the intra-system similarity, we 22 identified unique molecular formulae for each ecosystem and compared their main 23 characteristics. Our data indicate a pH influence on all samples and possibly a 24 vegetation influence on soil water samples. We interpreted the lack of nitrogen25 containing compounds in the surface water and the lower molecular size in the soil 26 water as related to higher microbial activity and reworking in soils and the lack of 27 aromatic compounds in surface waters as the result of photo degradation.