Marine organic matter chemical properties

The integration of biotic and abiotic dynamics also needs to take into account interactions between organisms and chemical properties of the environment, which are stmctured, not only by the synthesis of metabolites, but also by local disturbances of the physicochemical equilibria. The study of organic matter degradation processes, in the form of particulate or macrodebris, in benthic marine enviromnents, combined with that of community diversity and d5rnamic, helps illustrate this integration. 

Humic substances in marine sediments originate from both marine and terrestrial sources of organic matter, depending on the nature of sedimentary input. In some cases, a set of criteria based on chemical properties makes it possible to determine their origin. However, these criteria are less clear-cut than those established for kerogens. 

The fluorescence decay rates of samples of dissolved organic matter of marine and terrestrial origin have been measured. The lifetimes were all closely similar (2-2.4 ns) despite their widely different origins and histories. Implications of this similarity to other physical and chemical properties of humlc/fulvlc substances Is discussed as Is the Interpretation of the deactivation pathways of the excited states of marine chromophores. 

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