Pacific Ocean depth

Important ore deposits are found in Zaire, Morocco, and Ganada. The U.S. Geological Survey has announced that the bottom of the north central Pacific Ocean may have cobalt-rich deposits at relatively shallow depths in water close to the the Hawaiian Islands and other U.S. Pacific territories. 

You have been asked to prepare an outline design for the pressure hull of a deep-sea submersible vehicle capable of descending to the bottom of the Mariana Trench in the Pacific Ocean. The external pressure at this depth is approximately 100 MPa, and the design pressure is to be taken as 200 MPa. The pressure hull is to have the form of a thin-walled sphere with a specified radius r of 1 m and a uniform thickness t. The sphere can fail in one of two ways ... 

In the corrosion protection of marine structures, it is often found that the corrosion rate decreases strongly with increasing depth of water, and protection at these depths can be ignored. Investigations in the Pacific Ocean are often the source of these assumptions [7], However, they do not apply in the North Sea and other sea areas with oil and gas platforms. Figure 16-1 is an example of measurements in the North Sea. It can be seen that flow velocity and with it, oxygen access, is responsible for the level of protection current density. Increased flow velocity raises the transport of oxygen to the uncoated steel surface and therefore determines the... 

Little scientific examination of the deterioration of materials at depth has been undertaken except that by the US Naval Civil Engineering Laboratory and Naval Research, Laboratory. The results of this work were reported by Reinhart in 1966 and more recently the work has been reviewed by Kirk . Typical corrosion data for a selection of metals exposed in the Pacific Ocean at several sites and for different times are shown in Table 2.19 and are compared with results obtained in surface waters at Wrightsville Beach by International Nickel Inc. 

Many hydrologic reservoirs can be further subdivided into smaller reservoirs, each with a characteristic turnover time. For example, water resides in the Pacific Ocean longer than in the Atlantic, and the oceans surface waters cycle much more quickly than the deep ocean. Similarly, groundwater near the surface is much more active than deep reservoirs, which may cycle over thousands or millions of years, and water frozen in the soil as permafrost. Typical range in turnover times for hydrospheric reservoirs on a hillslope scale (10-10 m) are shown in Table 6-4 (estimates from Falkenmark and Chapman, 1989). Depths are estimated as typical volume averaged over the watershed area. 

The area, volume and average depth of the ocean basins and some marginal seas are given in Table 10-1. The Pacific Ocean is the largest and contains more than one-half of the Earth s water. It also receives the least river water per area of the major oceans (Table 10-2). Paradoxically it is also the least salty (Table 10-3). The land area of the entire Earth is strongly skewed toward the northern hemisphere. 

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).)...

Fig. 18-1 Benthic foraminiferal oxygen isotope record from 3477 m water depth in the eastern tropical Pacific ocean from Ocean Drilling Program site 677 (Shackleton et al, 1990). ratios are expressed in the S...

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. 

Mid-depth maxima are produced by mid-depth sources of metals. Some of these maxima are created by remineralization of detrital biogenic particles, such as seen in Figure 11.4f for cadmium. Others are caused by lateral transport of metals mobilized from coastal sediments as illustrated in Figure 11.17(a) for manganese. Mid-depth maxima can also result from hydrothermal emissions as shown in Figure 11.19 for Mn (aq) and He(g) at a site in the Eastern North Pacific Ocean. Hydrothermal fluids are emitted into the ocean from chimneys located atop the East Pacific Rise at water depths of about 2500 m. After entering the ocean, the Mn and He are entrained in subsurfece currents and... 

The sediment oxygen penetration depth as a function of water coiumn depth in the Atlantic Ocean (open symbols) and Pacific Ocean (closed symbols). Source-. From Martin, W. R., and F. L. Sayles (2003). Treatise on Geochemistry, Elsevier. 

North Atlantic to 500 m in the North Pacific. This reflects an increasing addition of CO2 to deep waters as meridional overturning circulation moves them from the Atlantic to the Indian and then to the Pacific Ocean. Thus, as a water mass ages, it becomes more corrosive to calcium carbonate. Since aragonite is more soluble than calcite, its saturation horizon lies at shallower depths, rising from 3000 m in the North Atlantic to 200 m in the North Pacific. 

Parameters influencing the distribution of calcium carbonate with increasing water depth in equatorial Pacific sediment. Note that fi is reported as a percentage (%). Source From van Andel, Tj. H., et al. (1975). Cenozoic History and Paleoceanography of the Central Equatorial Pacific Ocean, Geological Society of America, Boulder, CO, p. 40. 

Figure 8,37 REE concentration profiles with depth in Atlantic and Pacific Oceans.

Rakestraw NM, Rudd DP, Dole M (1951) Isotopic composition of oxygen in air dissolved in Pacific Ocean water as a function of depth, J Am Chem Soc 73 2976... 

The seasonal cycle of CCN has also been shown to be correlated with that of cloud optical depth in one remote marine area (Boers et al., 1994), and the isotope composition of non-sea salt sulfate over remote regions of the southern Pacific Ocean has been shown to be consistent with a DMS source (Calhoun et al., 1991). 

The fact that increased Slurry d does not adversely affect SE sensitivity is further illustrated in Fig 7, which shows the variation of d and sensitivity with w content of a SE containing TNT. Note that max d and sensitivity occur at the same w content. This implies that this SE can be used under high hydrostatic pressures (which will squeeze it to high d) which is indeed the case, since it has been shot at a one mile depth in the Pacific Ocean (Ref 5)... 

At their sampling sites in the Pacific Ocean, Santosa et al. (1997) found that MMA(V) and DMA(V) concentrations were highest at the surface with 0.012-0.016 pg L-1 and 0.048-0.185 pg L-1, respectively. The concentrations sharply declined to depths of 200 m. From depths of 200 to at least 5000 m, MMA(V) and DMA(V) concentrations stabilized at about 0.003 pg L-1 (Santosa et al., 1997). Santosa et al. (1996), 703 argue that the presence of methylarsenic in deep ocean waters is probably not due to diffusion from ocean floor sediments. Instead, the deep water methyl forms may result from the diffusion of methylarsenic-bearing surface waters, the circulation of surface waters to greater depths, and the tendency of methylarsenic not to appreciably sorb onto iron (oxy)(hydr)oxides particles. 

Figure 12.2 Observations of total inorganic carbon, nitrate, total inorganic phosphorus, oxygen and H+ in the North Pacific Ocean a ef a/., in prep.). The total inorganic-carbon concentration in this figure is also shown resolved into its components, HCO3, CO and H cal axes here and in subsequent figures give depth in kilometres. Dominant species of each element are shown adjacent to each figure.

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