Vertical South Atlantic Ocean

Fig. 27. Vertical profiles for a station in the South Atlantic Ocean (data from German et al. 1995) (a) dissolved concentrations of Nd and Er and (b) dissolved concentrations of Nd and Er normalized to their respective...

Fig. 11-9 (a) The vertical distributions of alkalinity (Aik) and dissolved inorganic carbon (DIC) in the world oceans. Ocean regions shown are the North Atlantic (NA), South Atlantic (SA), Antarctic (AA), South Indian (SI), North Indian (NI), South Pacific (SP), and North Pacific (NP) oceans. (Modified with permission from T. Takahashi et ah, The alkalinity and total carbon dioxide concentration in the world oceans, in B. Bolin (1981). Carbon Cycle Modelling," pp. 276-277, John Wiley, Chichester.)... 

PFOA observations To evaluate MPI-MCTM model results observational data of PFOA from ship cruises in the Atlantic, Indian and Pacific Oceans were taken from literature (summarised in Yamashita et al (2008)). The data was collected between 2002 and 2006 in a global ocean monitoring initiative. Samples were taken from ocean surface water. Vertical profiles were sampled in the Labrador sea, the Mid Atlantic ocean, the South Pacific ocean and the Japanese sea, where water probes were done at several depths down to 5500 m. The limit of quantification for PFOA was determined as 6 pg/L. 

Vertical distributions of total dissolved inorganic carbon (TDIC) in the subtropical South Atlantic (19°S 16°W) and equatorial North Pacific (9°N 135°W) oceans. These are WOCE data obtained from Java Ocean Atlas. 

Figure 4.7. The mean vertical distribution of (a) alkalinity and (b) total CO2 concentration normalized to the mean world ocean salinity value of 34.78. NA = North Atlantic, SA = South Atlantic, NP = North Pacific, SP = South Pacific, NI = North Indian, SI = South Indian, and A A = Antarctic region. (After Takahashi etal., 1980b.)...

Figure 13. The vertical distribution of alkalinity (a) and dissolved inorganic carbon in the World s Ocean. Ocean regions are shown as NA (North Atlantic), SA (South Atlantic), AA (Antarctic). SI (South Indian), Nl (North Indian), SP (South Pacific) and NP (North Pacific) (Molten, 1992).

The density of seawater thus depends both on its temperature and salinity. Highly saline waters at about 4°C are the most dense and will tend to sink, whereas warm, less saline water is less dense, and will tend to rise. This behavior has important implications for vertical motions in the sea. Descent of surface waters to the deep ocean is possible only where saline waters are cooled. This actually occurs in only a few locations, most notably in the North Atlantic off Greenland, and in the Weddell Sea, part of the Antarctic Ocean south of the Atlantic. North Atlantic deep water has a temperature of 2.5°C and a salinity of 35 g salt per kg of seawater. Deep water forming in the Weddell Sea has a temperature of — 1.0°C and a salinity of 34.6 g salt per kg seawater. In both of these locations, saline surface waters are cooled and sink, a process known as downwelling. The surface waters are made saline by evaporation nearer the equator in the case of the North Atlantic, and by the formation of sea ice in the case of the Weddell Sea. Shallower downwelling, to intermediate depths in the oceans, also occurs in areas of high evaporation. 

---