Atlantic Ocean mean depth

Fig. 1. Mean values of live epifaunal F. wuellerstorfi (squares), C. pachyderma (diamonds), and L. lobatula (dots) from five stations, as well as values of live infaunal G. affinis (crosses), F. mexicana (triangles), and B. mexicana (open circles) from seven, four, and ten stations, respectively, plotted versus sediment depth. Error bars give standard deviations of means of stations. Stations are in the South Atlantic Ocean along the southwest African continental margin. Bottom water values at stations he exactly within the range of F. wuellerstorfi...

Riley, 1975). The 11 ions, except for iodine, compose more than 99.9% of salinity. Iodine is one of the most abundant micronutrients in seawater, with a total concentration of 5 X 10 to 6 X 10 g-l (0.4-0.5pM). Other micronutrients, such as nitrogen and phosphorus and many trace ions, are also contained therein. The three main oceans (i.e., the Atlantic, Indian, and Pacific oceans), including adjacent seas, occupy 70.8% of the earths surface (total sea area of 360.8 X 10 km ). Of the sea area, the ratio of the continental shelf (less than 200m deep), between 200 and 2000 m deep, and over 2000 m deep is 7.6, 8.5, and the remaining 83.9%, respectively. The total volume of seawater is 1.37 X 10 m (mean depth 3795 m) (Bowden, 1975). The ocean is thus a huge reservoir of iodine. 

Unfortunately, the Baltic Sea is one of such inland seas, its depths being predominantly only 40 - 100 m. In addition, the Baltic Sea is subjected to considerable man-made pollution. We may have regrets that after World War II the victors over fascism failed to get the means to convey transports with chemical ammunition to deep-seated breaks in the Atlantic Ocean. 

Figure 2 Horizontal gradients of the annual mean concentration of (a) silicic acid ( jtmol kg ) at 3,000 m depth in the world s oceans (source NODC), and (h) dissolved zinc (nmol kg ) at a depth of 3,000 m based upon the deep-water relationship ([Zn] = 0.05[H4SiO4] - - 0.8) between silicic acid and dissolved zinc from stations in the North Atlantic (Bmland and Franks, 1983 Martin et ah, 1993), North Pacific (Bruland, 1980 Martin et al., 1989 Bruland et al., 1994), and Southern Ocean (Martin et al., 1990).

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