Characterization of a major refractory component of marine dissolved organic matter
2006; Elsevier BV; Volume: 70; Issue: 12 Linguagem: Inglês
10.1016/j.gca.2006.03.021
ISSN1872-9533
AutoresNorbert Hertkorn, Ronald Benner, Moritz Frommberger, Philippe Schmitt‐Kopplin, Matthias Witt, Karl Kaiser, A. Kettrup, John I. Hedges,
Tópico(s)Atmospheric and Environmental Gas Dynamics
ResumoRefractory carboxyl-rich alicyclic molecules (CRAM) are characterized in marine dissolved organic matter (DOM) using nuclear magnetic resonance spectroscopy and ultrahigh resolution mass spectrometry. CRAM are distributed throughout the water column and are the most abundant components of deep ocean DOM ever characterized. CRAM are comprised of a complex mixture of carboxylated and fused alicyclic structures with a carboxyl-C:aliphatic-C ratio of 1:2 to 1:7. CRAM are expected to constitute a strong ligand for metal binding, and multiple coordination across cations could promote aggregation and marine gel formation thereby affecting CRAM reactivity and the bioavailability of nutrients and trace metals. It appears CRAM are ultimately derived from biomolecules with structural similarities to sterols and hopanoids. The occurrence of CRAM in freshwater and terrestrial environments seems likely, considering the global distribution of biomolecules and the similarities of biogeochemical processes among environments.
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