Current circumpolar

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. 

The Circumpolar Current is a blend of waters of North Atlantic ( 47%) and Antarctic margin ( 53%) origin (Broecker, 1997). This current is referred to as the Pacific Common Water and is the source of deep water to the Indian and... 

Smetacek, V., de Baar, H. J. W., Bathmann, U. V. et al. (eds) (1997). Ecology and biogeochemistry of the Antarctic Circumpolar current during austral spring Southern Ocean JGOFS Cruise ANT X/6 of R.V. Polarstem. Deep-Sea Res. II44,1-519. 

Fig. 6 Geographic origin of the four P. antarctica strains (Table 2). To indicate the position of the Antarctic circumpolar current (ACC) encircling the Antarctic a schematic presentation was chosen (Lange et al. 2002 Olbers et al. 1962). [1 SK21, 2 SK22,3 D5, 4 Al-3]...

Coale KH, Wang X, Tanner SJ, Johnson KS (2003) Phytoplankton growth and biological response to iron and zinc addition in the Ross Sea and Antarctic Circumpolar Current along 170°W. Deep Sea Res II 50 635-653... 

Vaillancourt RD, Marra J, Barber RT, Smith WO Jr (2003) Primary productivity and in situ quantum yields in the Ross Sea and Pacific Sector of the Antarctic Circumpolar Current. Deep-Sea Res II 50 559-578 van Leeuwe MA, Stefels J (1998) Effects of iron and light stress on the biochemical composition of Antarctic Phaeocystis sp. (Prymnesiophycea). II. Pigment composition. J Phycol 34 496-503... 

Law, C. S., and Ling, R. D. (2001). Nitrous oxide flux and response to increased iron avadabdity in the Antarctic Circumpolar Current. Deep-Sea Res. 7/48, 2509—2527. 

The NO3 content of upweUing water is strongly influenced by the location of a system (Codispoti et al., 1982) in the global oceanic conveyer belt that transports deep water through the ocean basins (Broecker and Peng, 1982, their Fig. 1.12). From the North Atlantic to the Pacific and Indian Oceans through the Antarctic Circumpolar Current, there are increasing nutrients, from the faUout of surface productivity. 

Paleoproductivity studies in the Southern Ocean, where the deep-reaching Antarctic circumpolar current causes substantial sediment redistribution, have been especially dependent on the °Th-profiling method to obtain accumulation rates of opal, excess barium, organic carbon, and other paleoproductivity proxies (Anderson et al., 2002, 1998 Chase et al., 2003a Francois et al., 1997, 1993 Frank, 1996 Frank et al., 2000 Kumar et al., 1995). Studies of the Atlantic and Indian sectors of the Southern Ocean concluded that productivity in regions south of the Antarctic polar front was lower... 

Frank M. (1996) Reconstructions of Late Quaternary environmental conditions applying the natural radionucUdes Th, e, Pa and a study of deep-sea sediments from the eastern sector of the Antarctic Circumpolar Current System. Rep. Polar Res. 186, 1—136. 

Friedrich J. and Rutgers van der Loeff M. M. (2002) A two-tracer ( Po- Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current. Deep-Sea Res. I Oceanogr. Res. Pap. 49(1), 101-120. 

Stations in the Circumpolar Current South of New Zealand, Nature (1975) 253,107. 

Figure 5.1. Approximate circumpolar paths of the principal fronts within the Antarctic Circumpolar Current based on historical data compilation. Adapted from Whitworth (2).

As the Antarctic Bottom Water flows north, it gradually mixes with the southward flowing North Atlantic Deep Water, which lies immediately above. As the North Atlantic Deep Water flows to the south, it incorporates not only the Antarctic Bottom Water but also the Mediterranean Water and the Antarctic Intermediate Water which lie above. The North Atlantic Deep Water is eventually entrained into the Antarctic Circumpolar Current and flows unimpeded into the Indian and Pacific Oceans. 

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