Indian Ocean depth profile

Figure 4.24. Estimates of Peterson and Prell (1985a) for the loss of carbonate to dissolution in the equatorial Indian Ocean. Depth profiles were calculated using the n0(= initial weight % non-carbonate fraction) values given in the figure.

Fig. 10-20 Observed depth profiles of (a) phosphate, (b) dissolved inorganic carbon (TC), (c) alkalinity (TA), and (d) oxygen for the Atlantic, the Indian, and the Pacific Oceans as indicated. Data are from GEOSECS stations within 5° of the Equator in each ocean. (Modified from Baes et al. (1985).)...

Typical vertical saturation profiles for the North Atlantic, North Pacific, and Central Indian oceans are presented in Figure 4.10. The profiles in the Atlantic and Indian oceans are similar in shape, but Indian Ocean waters at these GEOSECS sites are definitely more undersaturated than the Atlantic Ocean. The saturation profile in the Pacific Ocean is complex. The water column between 1 and 4 km depth is close to equilibrium with calcite. This finding is primarily the result of a broad oxygen minimum-C02 maximum in mid-water and makes choosing the saturation depth (SD) where Oc = 1 difficult (the saturation depth is also often referred to as the saturation level SL). 

N2O depth profiles from regions with oxic water masses such as found in the major parts the Atlantic (Fig. 2.2), Pacific, and Indian Oceans are characterized by a subsurface N2O maximum which coincidents with the minimum of dissolved O2 and the maximum of N03 (Butler et al., 1989 Cohen and Gordon, 919 Oudot et al., 1990, 2002). The N2O subsurface maximum is less pronounced or even absent... 

Figure 1 Depth profiles of (a) XCO2, (b) dissolved CO2, (c) silicic acid, (d) nitrate, and (e) phosphate from the Indian Ocean (27° 4 S, 56° 58 E GEOSECS Station 427) (source Weiss et al, 1983).

Neodymium-isotope ratios of intermediate and deep water in the Indian Ocean are intermediate to the Atlantic and Pacific. They generally fall between s d = 1 to —9, and are consistent with domination by northward flowing circumpolar water (Bertram and Elderfield, 1993 Jeandel et al., 1998). A depth profile east of southern Africa (Figure 7) displays the same zig-zag pattern as South Atlantic intermediate and deep water, reflecting advection of NADW into the western Indian Ocean (Bertram and Elderfield, 1993). 

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... 

Depth profiles of total alkalinity (Aj) in the Atiantic, Antarctic, indian and Pacific Oceans. Piotted in Ocean Data View, using data from the e-WOCE compiiation. 

Analogous surface maxima were observed studying the distribution of Cu along profiles of the Pacific Ocean and Indian Ocean (83, 135). In both cases the authors emphasized the presence of a minimum of concentration at a depth of about 500 m and they explained this as the effect of an important local surface source. In particular, Boyle et al. provided evidence that the surface maxima may be transient features resulting from the advecting of Cu-rich near-shore surface water into the more central regions of the oceans, while Saager et al. hypothesized the contribution of atmospheric particles to the surface concentration (19). 

Vertical profiles and surface concentrations of DDT dissolved in the ocean were measured by Tanabe and Tatsukawa (1983). Water samples for depths down to 5000 m were taken on three cruises of the Ocean Research Institute, University of Tokyo and on a cruise by the University of Fisheries, Tokyo. The cruises were carried out between 1976 and 1981 in the Western Pacific, Eastern Indian and Antarctic oceans. 

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. 

Figure 15 shows typical profiles of "Ra in the oceans. Its concentration in surface waters falls in the range of 0.07+0.01 d.p.m. 1 which steadily increases with depth such that its abundance in the deep waters of the Pacific>Indian>Atlantic (Figure 15). Ra concentration in the North Pacific bottom water is 0.4 d.p.m. some of the highest in the world s oceans.

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