Biogeochemical Cycling in the Organic-Rich Coastal Environment

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The project focuses on a question of fundamental importance for understanding the global oceanic carbon cycle: What factors and processes control whether organic matter deposited in marine sediments will be remineralized or buried. Organic matter deposition, remineralization, and burial will be studied at sites along transects in a shallow, highly productive North Carolina coastal lagoon and on the upper continental slope off Cape Hatteras, NC. Specific objectives include: (1) determination of how the fraction of organic carbon deposition that is remineralized varies along these two coastal transects, (2) determination of sources and ages of the reactive fraction, (3) determination of the chemical composition of reactive and unreactive fractions of the organic matter at sites along these transects, and (4) determination of the effect of respiratory mode on organic matter remineralization rates and chemical composition of buried material. Objectives (1), (2), and (3) involve extensive field work while objective (4) involves as well-controlled laboratory microcosm study. Combining field data and laboratory experiments provides a powerful tool for directly testing hypotheses regarding the mechanisms by which environmental parameters influence organic matter reactivity.