Atlantic Ocean dissolution

Figure 2.14. The log of dissolution rate in percent per day versus the log of (1-fi). A = whole Indian Ocean sediment dissolved in deep-sea sediment pore water B = whole Pacific Ocean sediment dissolved in Atlantic Ocean deep seawater C = whole Atlantic Ocean sediment dissolved in Long Island Sound seawater (Morse and Berner, 1972) D = > 62 pm size fraction of the Indian Ocean sediment dissolved in Atlantic Ocean deep seawater, E = the 125 to 500 pm size fraction of Pacific Ocean sediment dissolved in Atlantic Ocean deep seawater F = 150 to 500 pm Foraminifera dissolved in the Pacific Ocean water column. (After Morse, 1978.)...

One of the more "aesthetically pleasing" relations was put forth for the eastern and western Atlantic Ocean basins by Berger (1977). In his plots (see Figure 4.21) the R0, FL and CCD were generally widely separated and usually close to parallel. The saturation depth (SD) was close to coincident with the R0 level. However, even this picture has problems. If the R0 and SD are closely coincident, how can the 50% dissolution occur that is required to produce the R0 level (Adelseck, 1978) ... 

Schneidermann N. (1977) Chapter 12. Selective Dissolution of Recent Coccoliths in the Atlantic Ocean. In Oceanic Micropalaeontology, Volume 2 (ed. A.T.S. Ramsay), 1009-1046. Academic Press Inc., New York. 

Thunell R.C. (1982) Carbonate dissolution and abyssal hydrography in the Atlantic Ocean. Mar. Geol. 47, 165-180. 

Figure 8, A detailed profile of calcite and aragonite saturation states and sediment marker depth in the Northwestern Atlantic Ocean, (Percentages are estimates of the amount of calcite dissolution which must occur to produce a given marker level.)...

Honjo, S. and Erez, J. Dissolution rates of calcium carbonate in the deep ocean an in situ experiment in the North Atlantic Ocean, Earth Planet Sci. Lett, (in press). 

The distribution patterns of coccoliths and foraminifera differ significantly in deep-sea sediments (Schneidermann, 1973 Roth et al, 1975). In most sediments the more easily dissolved coccoliths are missing. Even in areas where the overlying water is supersaturated with respect to calcite (e.g., 3,000 m in the Atlantic Ocean Schneidermann, 1973), significant dissolution of coccoliths has been observed. Solution-resistant coccoliths, however, may survive in sediments in which all foraminiferal tests have been dissolved. Schneidermann (1973) used these characteristics to create additional subdivisions of the region near the CCD, and Roth et al. (1975) emphasized that coccolith and foraminifera solution indices can be used in a complementary manner. Coccoliths are good indicators of dissolution above the lysocline, whereas foraminifera are better indicators of dissolution below the lysochne. 

Figure 2 Rate of carbonate dissolution from deep-sea sediment versus (1 — O). SoUd Une from Hales and Emerson (1996), dotted line from Keir (1980), dashed line from Atlantic Ocean, and dotted and dashed line from Pacific Ocean sediment results of Morse (1978). Note that Hales and Emerson (1996) used a different calcite solubility product.

They suggested that most of the carbonate dissolution in the deep ocean (Fig. 9.5) occurs within the sediments (85 %). The extension of their results from Pacific and Indian Ocean to the Atlantic Ocean leading to 120 10 molyr of global dissolved carbon fluxes from sediments may, however, be critical because of the completely different deep-water conditions in the Indo-Pacific and the Atlantic. Deep ocean waters in the Indian and Pacific Oceans are known to be much older and depleted in CO implying that a much higher proportion of calcite dissolution contributes to the total alkalinity input there. However, despite this problem of different bottom-... 

Milliman, J.D. Dissolution of calcium carbonate in the Sargasso sea (Northwest Atlantic), p. 641-654, in Andersen, N.R. and Malahoff, A., eds., "The Fate of Fossel Fuel CO2 in the Oceans,", Plenum Press, New York, 1977. 

Aluminum is the best illustration of a trace metal with a scavenged-type distribution in the oceans. The major external input of aluminum is from the partial dissolution of atmospheric dust delivered to the surface ocean. Vertical profiles in the Mediterranean, the North Atlantic, and the North Pacific are presented in Figure 4. Extremely elevated concentrations of dissolved aluminum are observed in the Mediterranean Sea (Hydes et al., 1988), a region that receives a high atmospheric input of dust. Concentrations in... 

Data from GEOSECS and TTO Expeditions The GEOSECS and TTO (Transient Tracers in the Oceans) programs have provided a large source of data in the Atlantic (see Broecker 1985, and Takahashi et al., 1985). The interpretation of the chemical data from isopycnal surfaces yields a Redfield ratio of P/N/C/O2 of 1 16 103 172. The ratio of P/CaCO dissolution has been estimated to be about 1 12. This indicates that the ratio of CO2 produced by the oxidation of organic carbon to that derived from the dissolution of CaC03 is about 10 1. 

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