Dissolved organic matter (DOM) in the oceans is one of the major global carbon reservoirs. It is subject to various degradation and remineralizing processes, constitutes the nutritional basis for mixotrophic and heterotrophic consumers and its dynamics dertermine elemental sequestration balance in the oceans. Radiocarbon dating allows to determine average ages of up to 6000 year for DOM compounds. This can be explained by ad hoc models classifying compounds into classes of different bio-availability. Intriguingly, recent studies revealed that the enormous diversity and a corresponding huge dilution of any given compound may likewise explain resistance to degradation.

We develop models for the analysis of diversification and degradation of DOM compounds to point out and test alternative hypotheses regarding DOM persistence and distribution of concentrations and ages of different compounds. Further, we integrate the microbial component into mechanistic models for global distributions of organic DOM.