Antarctic Convergence

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... 

There are substantial differences between glaciation of the southern and the northern polar regions. In the south, Antarctica is a sole continent in polar position. It is surrounded by large oceans, and is screened from warm equatorial currents at about 60 S by the Antarctic Convergence. In the north, a relatively small but deep Arctic Ocean is surrounded by continents, its waters coihmimicating with the Atlantic and the Pacific oceans by narrow straits, the Nansen Strait and the Bering Strait, respectively. 

Sampling in Mediterranean deep waters has revealed the first secondary n tabolites from brachiopods and unique 10-hydroxyeicosa- and docosapolyenoic acids from scleractinian corals. That these fetty acids have also been foimd in a deep-water pre-Antarctic antipatharian coral (Table 9.III) must be attributed to convergence. Deep-water Mediterranean medusae and a lithistid sponge from New Caledonia, Corallistes sp., contain huge amounts of free porphyrins. 

Chen, L., A.L. DeVries, and C.-H. C. Cheng (1997b). Convergent evolution of antifreeze glycoproteins in Antarctic notothenioid fish and Arctic cod. Proc. Natl. Acad. Sci. USA 94 3817-3822. 

Within the main thermocline, relatively low-NOs waters of the southern subtropical gyre are separated from those rich in NOs in the monsoon gyre to the north and the sub-Antarctic zone to the south by the Hydrochemical Front and the Subtropical Convergence (STC), respectively (Fig. 14.IB). The maximum in NOs generally occurs in the 1-2 km depth range north of the STC, and at... 

Fig. 9-7 Global map of major ocean currents. AND, Antarctic divergence STC, subtropical convergence ARC, Arctic convergence.

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