Deposition of Dissolved and Particulate-Bound Chemicals from the Surface Ocean

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The deep ocean is an important reservoir and sink for chemicals, such as persistent organic pollutants (POPs) (Dachs et al., 2002). Over the last decade, several studies have attempted to parameterize the settling fluxes of particle-associated and dissolved compounds to the deep ocean (Jurado et al., 2004, 2005; Lohmann et al., 2006a). Indeed, this process, which was often overlooked in the past, is now considered one of the most important global sinks of chemicals, together with atmospheric degradation (Wania and Daly, 2002; Lohmann et al., 2006b). The overall paucity of regional and global settling estimates of chemicals is related to both the difficulties of sampling this process and to the complexity of the processes driving the sinking fluxes of organic matter and associated pollutants (Dachs et al., 1999, 2000). While our previous work involvedwill affect organic compounds in general. In this chapter we discuss and quantify the importance of deepmarine waters as a sink for chemicals. Specifically, the importance of the “biological pump” (phytoplankton production) and the “physical pump” (deep water formation) as removal processes of chemicals are discussed, rates are quantified, and methods for estimating these fluxes are provided for a variety of cases. A major vector or vehicle for chemical transport to deep marine waters is organic matter (OM) or organic carbon (OC). Note that in general, OC is actually the measured quantity (by CHN analysis), but it is often used synonymously for OM. Fluxes of OM can be obtained by multiplying the FOC values by 2, which is based on an averaged composition of a diatom, and implies that OM is 50% OC (Hedges et al., 2002).

Publication Title, e.g., Journal

Handbook of Chemical Mass Transport in the Environment