Calcium Carbonate Sedimentation in the Global Ocean: Linkages Between the Neritic and Pelagic Environments

Other than fluvial sediment, calcium carbonate (CaCO3) is the greatest source of sediment in the present-day ocean. Interest in carbonate sedimentation extends beyond geologists because the carbonate system involves biologic and geochemicalprocesses. Carbonate production, for example, releases CO2 but its accumulation becomes a major sink for inorganic carbon.Unlike fluvial sediments, modern carbonates accumulate more or less equally in the neritic and pelagic environments. Neritic carbonates (benthic) are characterized by rapid production of (mostly) metastable aragonite and magnesian calcite:pelagic production of (primarily) calcite in the open ocean occurs at much slower rates but overmuch larger areas than does neritic production (Table 1). A global understanding of the production, preservation, and accumulation of calcium carbonate thus necessitates understanding both theneritic and pelagic systems, even though communication between researchers in the two subdisciplines often has been minimal.