South Atlantic water

Passage values (Figure 7). This may indicate a source of neodymium with high isotope ratios in the South Atlantic. However, it is premature to conclude that deep South Atlantic neodymium-isotope ratios overstep the Southern Ocean values, for the following reasons. The maxima for all of the deep South Atlantic waters are between SNd = 7 to —9, more variable than presently available data from the Drake Passage but still quite similar. This range is also similar to circumpolar Fe-Mn sediments (Albare(c)de et al., 1997). Depth profiles from the western Indian Ocean near southern Africa are similar to the South Atlantic and Drake Passage, but like the South... 

The frequency distribution of POC with depth as reported by this author is of some interest (Fig. 3) and demonstrates a close agreement between the POC distribution in the Atlantic and Pacific Oceans, with the exception of surface vedues which are higher in South Atlantic waters. These differences in surface waters are however not significant because of the heterogeneity of the samples containing both living matter and detritus. The effects of seasonal or local hydrographic conditions are limited mainly to surface waters, which as a consequence show differences in productivity. 

Over the past decade, plastic debris has become a common feature of beaches and coastal waters adjoining populated areas of Europe (36-38), the Mediterranean (39-41), North and Central America (42-44) and New Zealand (45). Plastics are also present in the open ocean both near the major shipping lanes and in the most remote regions of the world (the Arctic (46), the Benguela Current (47), the Cape Basin area of the South Atlantic (48), the Humboldt Current in the South Pacific (49), and the Antarctic (50, 51). 

The conveyor belt is shown schematically in Fig. 10-11. Warm and salty surface currents in the western North Atlantic (e.g., the Gulf Stream) transport heat to the Norwegian-Greenland Seas where it is transferred to the atmosphere. This heat helps moderate the climate of northern Europe. The cooling increases the density resulting in formation of the now cold and salty North Atlantic Deep Water (NADW) (Worthington, 1970). The NADW travels south through the North and South Atlantic and then joins the Circumpolar Current that travels virtually unimpeded in a clockwise direction around the Antarctic Continent. 

Deep water also forms along the margins of Antartica and feeds the Circumpolar Current. The Weddell Sea, because of its very low temperature, is the main source of Antarctic Bottom Water (AABW) which flows northward at the very bottom into the South Atlantic, and then through the Verna Channel in the Rio Grande Rise into the North Atlantic. It ultimately returns southward as part of the NADW. 

Class and Ballschmitter (1988) suggested that brown algae may be the source of the <0.01-0.03 ppt of 1,2-dibromoethane found in the marine water samples collected from the North and South Atlantic Oceans. 

Evidence has been detected of the biomethylation of cadmium. Studies with differential pulse anodic stripping voltammetry have shown detectable amounts of monomethylcadmium ion, H3CCd+, in surface water of the South Atlantic.5 Examination of water from some Arctic meltwater ponds showed that up to half of the cadmium present in the water was in the monomethylcadmium ion form. 

Schreitmuller, J., Ballschmiter, K. (1995) Air-water equilibrium of hexachlorocyclohexanes and chloromethoxy-benzenes in North and South Atlantic. Environ. Sci. Technol. 29, 207-215. 

Even in the deeper coastal waters of the South Atlantic Bight (SAB) (USA)... 

The density of the water controls the deepwater circulation. If the density of a water body increases, it has a tendency to sink. Subsequently, it will spread out over a horizon of uniform circulatory system is also known as thermohaline circulation. As shown in Figure 5 of the ocean conveyor belt, the densest oceanic waters are formed in Polar Regions due to the relatively low temperatures and the salinity increase that results from ice formation. Antarctic Bottom Water (ABW) is generated in the Weddell Sea and flows northward into the South Atlantic. North Atlantic Deep Water (NADW)... 

Diverse processes can form intermediate waters within the water column. In the southern South Atlantic, the NADW overrides the denser ABW. Antarctic Intermediate Water results from water sinking along the Antarctic Convergence ( 50°S). Relatively warm, saline... 

Figure 4.10 Enantiomer fractions (EFs) of a-HCH in water and air of the southern Atlantic Ocean as a function of latitude. (Reproduced with permission from Deep-Sea Research Part II Topical Studies In Oceanography, Air-water gas exchange of a-hexachlorohexane enantiomers in the South Atlantic Ocean and Antarctica, by Liisa M. jantunen, Henrik Kylin and Terry F. Bidleman, 51(22-24), 2661-2672. Copyright (2004) Elsevier)...

Jantunen, L.M. Kylin, H. Bidleman, T.F, Air-water gas exchange of a-hexachlorocyclohexane enantiomers in the South Atlantic Ocean and Antarctica Deep-Sea Res. //2004,51,2661-2672. 

Schmidt also measured the H2 content of surface waters in the North and South Atlantic Oceans. The data varied from 0.8 to 5.0 x 10 mL/L(H20), corresponding to saturation factors of E = 0.8 5.4, where F = represents equilibrium conditions between surface water and air, while F < 1 or E > 1 indicate undersaturation or supersaturation, respectively. The H2 supersaturation in ocean water may be due to the production of hydrogen by microbiological activity. 

Schneider, R. R., P. J. Muller, and M. Zabel. 1996. "Biogenic opal in the eastern South Atlantic patterns of surface water productivity, sedimentary accumulation, and benthic silicate fluxes in relation to oceanic and fluvial nutrient supply." In OPALEO On the Use of Opal as a PaleoProductivity Proxy, ed. O. Ragueneau, A. Leynaert, and P. Treguer (Brest, France), pp. 98-103. 

Zubkov, M. V., and Tarran, G. A. (2005). Amino acid uptake of Prochlorococcus spp. in surface waters across the South Atlantic Subtropical Front. Aquat. Microb. Ecol. 40, 241—249. 

Figure 13.2 Section of (A) nitrate versus depth and (B) nitrate versus potential density (sigma theta) using combined data from the 2003 (North Atlantic) and 2005 (South Atlantic) occupations of the A16 line. North Atlantic DeepWater (NADW), Antarctic Bottom Water (A ABW) and Antarctic Intermediate Water (AAIW) are indicated. Units pmol kg. ...

Nitrate-rich signatures of Antarctic Bottom Water (AABW) and Antarctic Intermediate Water (AAIW) extend northward, reflecting the high surface concentrations where these water masses are formed. These water masses are also evident in the zonal structure of the North and South Atlantic, and nitrate-rich (>30 iM) AAIW is evident in the South Atlantic (Fig. 13.3) at mid-depth, along with a hint of AABW with elevated nitrate concentrations in the deep western part of the basin. There is... 

Ganachaud and 0.4 1991-1994 drawdown of inorganic carbon in nitrate depleted waters (data selection criteria SST >20°C NO3- <0.1 pmol kg ), converted to N using C N molar ratio of 7 Subtropical South Atlantic only inverse... 

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