9711596 Hatcher The role of macromolecular organic matter will be examined with respect to the long-term stabilization or sequestration of protein nitrogen in marine systems using the combined application of geochemical and biochemical tools. The study will focus upon samples already obtained from a natural mineral-matter depleted marine sediment (Mangrove Lake, Bermuda), oceanic organic-rich sediments from the Peru upwelling zone and the Santa Barbara Basin, oceanic sediment trap material, and on samples obtained from laboratory degradations of algae grown to enrich them in 13C and 15N. Electrophoretic techniques and NMR will follow the fate of protein in laboratory incubations during its incorporation into the macromolecular pool. Protein's role in forming macromolecular organic matter which resists degradation in sediments over the long term will be studied. To address this issue, a novel dual/selective labeling experiment will be used to examine any cross-coupling of carbon and nitrogen from each of two parallel but selectively labeled pools of algae during degradation. Understanding the mechanisms and processes involved in the formation of refractory nitrogen-containing organic material in sediments and sediment-trap material will improve our understanding of nitrogen cycling in marine systems and will also provide a conceptual framework for improved predictive models of global nitrogen cycling.
