Empirical relationships for use in global diagenetic models

A database containing published rates of sediment and pore-water transport and biogeochemical transformations has been established to derive empirical predictive equations to calibrate and parameterize global diagenetic models. Rates of sediment accumulation, organic carbon burial, organic matter decomposition via aerobic and anaerobic pathways and bioturbation (in terms of bioturbation coefficients) can be predicted quite well using exponential relationships with water depth as an independent variable. The relationships are corrected for skewness to reduce the bias inherent in the back transformation from a lognormal to an arithmetic estimate. Bioturbation is shown to be the dominant mode of sediment transport in the upper centimeters of oceanic sediments. The derived empirical relationships are combined with bathymetric maps to estimate globally integrated rates of benthic processes. Ocean margin sediments account for about 85% of the materials accumulating in the ocean and about 80-90% of the mineralization in marine sediments. (C) 1997 Elsevier Science Ltd.