North Atlantic Deep Water properties

A useful apphcation of preformed nutrient concentrations is that they are intrinsic to different water masses and sometimes can be used as conservative tracers. For example, the main sources of deep water in the Pacific Ocean are North Atlantic Deep Water (NADW), Antarctic Intermediate Water (AAIW) and Antarctic Bottom Water (AABW), all of which are at least partly homogenized in the Antarctic Circumpolar Water (AACW). It is not possible to determine how much of each of these sources contributes to Pacific deep water by using end member mixing of the conservative properties temperature and salinity because salinities of the end members are not sufficiently different. Since concentrations of DIP are well above detection limits in... 

Experience gained during the last decade in the determination of CBs in off-shore surface and deep waters has shown that concentrations are extremely low, much lower than reported earlier (see Table 22-1). Concentrations reported for the Mediterranean Sea (Tolosa et al, 1997 Schulz-Bull et al., 1997), the North Sea Schulz-Bull et al., 1991) and the Baltic Sea Schulz-Bull et al., 1995) were well above those found in surface waters of the open ocean Iwata et al., 1993 Schulz-Bull et a/.,1998). In deep-ocean water Schulz et al., 1988 Petrick et al, 1996 Schulz-Bull et al, 1998) much lower concentrations were found than in surface waters. In North Atlantic Deep Water, values of individual CBs were found to be < 0.01 pg/L, yet concentrations in solution were higher than those in suspended material on an equal volume basis. It turns out that the distribution of CBs between solution and suspension is determined primarily by molecular properties (characterized by octanol/water distribution coefficients). However, biological processes disturb the establishment of equilibria. This phenomenon has been observed in river water, in estuarine and coastal waters and during biologically active periods in the surface layer of the open ocean. 

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