Dissolved organic matter (DOM) in the ocean represents about 662 billion tons of C, 200 times more than living biomass. It is produced mainly by microbial primary production. The largest fraction this DOM old (>weeks to months) and both chemically biologically recalcitrant. remainder young (seconds weeks), labile surface active. Part latter changes rheological properties bulk phase water at ...

The depth variation of total organic carbon (TOC), organic matter composition, and porewater composition in marine sediments suggests that different components of the organic matter undergo decomposition at widely different rates. The decomposition of 14C-labeled organic substances was followed in sediment microcosms in the laboratory. The substances used were chosen to simulate a portion of ma...

A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temp...

A modified differential filtration was used to measure extracellular release of primary products by natural phytoplankton populations and subsequent incorporation of these products by bacteria. Water samples were incubated with I4C labelled bicarbonate for 6 h and 24 h , respectively. A time course experiment showed that 6 h are sufficient for attaining an approximate isotopic equilibrium betwe...

REFERENCIAS Y ENLACES [1] F. J. Stevenson, Humus Chemistry: Genesis, Composition, Reactions, Wiley Interscience, New York (1994). [2] G. R. Aiken, “Isolation and concentration technique for aquatic humic substances”, p. 363−385 in Humic Substances in Soil, Sediment and Water, G. R. Aiken, D. M. McKnight, R. L. Wershaw, P. MacCarthy, Edts., Wiley, New York (1985). [3] Y. Inbar, Y. Chen, Y. Hadar...