Studies of the Decomposition of Organic Matter in the Marine Environment

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This study continues research on the decomposition of organic matter, which comprises a major fraction of carbon in the ocean. The study is directed toward further defining pathways and rates of organic matter decomposition in the oceanic water column, from production in surface waters, through the zones of remineralization in the water column, to preservation in the underlying sediments. The decomposition of organic matter is one of the major processes controlling the chemical composition of seawater and sediments. On a global scale, oxic decomposition is the major pathway of degradation in marine sediments, with anaerobic processes consuming much less organic matter. However, the majority of carbon preservation occurs in anoxic systems, typically coastal marine sediments where organic matter sedimentation rates are highest. Understanding the controls on organic matter decomposition and carbon preservation is a key to interpreting changes in sedimentary carbon content, and thus paleoproductivity of the oceans. The major goals of this research are to investigate the formation of methane from, methylamines in particulate matter, to measure the effects of adsorption and desorption of organic compounds on their decomposition rates and mechanisms, to determine the influence of oxic vs anoxic conditions on decomposition, and to explore the use of cell-surface enzymes in the decomposition of amino acids and amines by phytoplankton and bacteria.