Many organic compounds, including both polar and nonpolar substances, are adsorbed by marine sediments. Adsorbed organic substances determine the physicochemical properties ofmostparticle surfaces in natural waters. Further,adsorptionaffects thr rate of decomposition of organic substancesbybacteria. The proposed research will investigate theadsorptionof the amino acids alanine, glutamic acid, lysine, andleucine:several alanine peptides, and the monosaccharide glucose. Thegoals are to determine which organic constituents ofsedimentsadsorb amino acids, the effects of adsorption ondecompositionrates, and the mechanisms of adsorption. THeapproach willinvolve both field studies on fresh, intactsediments andlaboratory experiments with extracted sedimentorganic matter.The results of these studies will help answer thequestion: Isadsorption responsible, in part, for variation indecompositionrates of different organic substances? Doesadsorptioncontribute to differences in decomposition rates of thesameorganic compound in sediments of differing composition?