The principal source of organic matter in marine systems is from in situ primary production by photosynthetic microorganisms. The bulk of the produced organic matter is remineralized in the water column and sediments, but a small fraction survives diagenesis to be preserved. Of particular importance to global carbon and nitrogen budgets is organic matter's inherent resistance to decay and its transformation into refractory substances, both of which remove it from the reactive biotic and abiotic marine cycles. Little is known, however, about the chemical composition of this refractory, macromolecular organic matter, or mechanisms contributing to its resistance during diagenesis.
Scientists from the State University of New York, Stony Brook and Old Dominion University propose to determine the biological and chemical basis for the observed distribution of protein, peptide, and amino acid pools in the marine environment. Specifically, they plan to compare the rates of competing chemical, physical, and biological reactions of peptides to gain a better understanding of the distribution, cycling, and fate of proteinaceous material in seawater. Through the use of state-of-the-art analytical methods (i.e., matrix-assisted laser desorption/ionization mass spectrometry-MALDI-MS, electrospray mass spectrometry coupled to Fourier transform ion cyclotron mass spectrometry-ESI FTICR, 2D nuclear magnetic resonance approaches) the principle investigators plan to synthesize peptides of biological interest and monitor their rates of production and removal. This would lead to observations of the importance of chemical and biological loss mechanisms in various environments with respect to change in light, pH, nutrients, and temperature.
As regards broader impacts, results from this study would provide a better understanding of the bioavailability of organic matter to microbes, the mechanisms where organic matter is rendered less available in the water column, and how organic matter is preserved. One graduate student and one undergraduate student from the State University of New York, Stony Brook, and one postdoc and one graduate student from Old Dominion University would be supported and trained as part of this project. Results and methods from this project would be integrated into graduate and undergraduate education and training at both universities.
