Pacific Ocean averages

Ninety per cent of destructive tsunamis occur within the Pacific Ocean, averaging more than two each year. The Pacific Tsunami Warning System, PTWS, is a communications network... 

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. 10-4 Average temperature/salinity diagrams for Pacific Oceans. (Reproduced with permission from G. L. Oceanography," pp. 138-139, Pergamon Press.)...

Table 1.11 Average composition of Pacific Ocean nodules and mineralogical composition of manganese nodules.

The average concentration and standard deviation of the Pacific Ocean waters ( xg/l) were 2.00 0.09 by neutron activation analysis, and 1.86 0.12 by atomic absorption spectrometry. For the Adriatic water the corresponding values were about 1.7 xg/l. The difference between the values for the same seawater is within the range to be expected from the standard deviations observed. 

Tsunogai and Nozaki [6] analysed Pacific Oceans surface water by consecutive coprecipitations of polonium with calcium carbonate and bismuth oxychloride after addition of lead and bismuth carriers to acidified seawater samples. After concentration, polonium was spontaneously deposited onto silver planchets. Quantitative recoveries of polonium were assumed at the extraction steps and plating step. Shannon et al. [7], who analysed surface water from the Atlantic Ocean near the tip of South Africa, extracted polonium from acidified samples as the ammonium pyrrolidine dithiocarbamate complex into methyl isobutyl ketone. They also autoplated polonium onto silver counting disks. An average efficiency of 92% was assigned to their procedure after calibration with 210Po-210Pb tracer experiments. 

Since iron can serve as a model for the behaviour of plutonium it is worth considering the behaviour of iron in the environment. Iron in oceanic water has been shown to exist principally as a non-filterable (0.45 q) form (162). This non-filterable form, in the case of the Atlantic Ocean waters, represented an average concentration of 0.2 jug/1 (163). Similar concentrations have been reported for the Pacific Ocean (164). In coastal waters the iron concentration is very variable (165). 

In the Pacific Ocean, most of the waters at 2500 m have a prefiormed phosphate concentration intermediate between NADW and AABW. Because preformed phosphate is a conservative tracer, it can be used to estimate the proportions of NADW and AABW present in the deep zones of the ocean basins. The average deep-water preformed phosphate concentration is 1.4 (jlM. This concentration would result from an equal-volume admixture of NADW and AABW. This conservative mixing estimate is based on the assumption that the preformed phosphate concentrations of the end-member water masses have remained constant over time scales at least as long as the mixing time of the ocean. 

North Atlantic Deep Water (NADW), which is formed with an initial 5 C-value between 1.0 and 1.5%c, becomes gradually depleted in C as it travels southward and mixes with Antarctic bottom water, which has an average 8 C-value of 0.3%c (Kroopnick 1985). As this deep water travels to the Pacific Ocean, its C/ C ratio is further reduced by 0.5%o by the continuous flux and oxidation of organic matter in the water column. This is the basis for using 8 C-values as a tracer of paleo-oceanographic changes in deep water circulation (e.g., Curry et al. 1988). 

Of the simple alkyl nitrates, methyl nitrate is present in the highest concentration. For example, in measurements made in Schauinsland, a rural area in Germany, concentrations of CH30N02 up to 216 ppt were measured. The median value, however, was only 19 ppt (Flocke et al., 1998). In the same studies, the median concentrations for ethyl nitrate, n-propyl nitrate, 2-pro-pyl nitrate, and 1-butyl nitrate were 9, 3, 12, and 2 ppt, respectively. The sum of the C,-C8 alkyl nitrates averaged 120 ppt, which is only 3% of the NO. Similarly, in rural Ontario, Canada, 17 different organic nitrates were identified in air, but their sum was only 0.5-3% of NOj. (O Brien et al., 1995). In aircraft measurements over the Pacific Ocean near Hawaii, average values for methyl nitrate near the surface were 6 ppt and the sum of C,-C5 alkyl nitrates was <5% of the total NO, (Ridley et al., 1997). 

Fig. 1. Regions where manganese nodules containing more than 1.8% nickel-copper occur in the northeastern equatorial Pacific Ocean. Numbers indicate average percent of nickel-copper in onc-dcgrcc squares. Areas a, b, and c indicate locations of activity carried out as part of Deep Ocean Mining Environmental Studies Program. (After McKelvey, U.S. Geological Surrey)...

Climate researchers Palutikof and Holt (2004) say that droughts appear to be linked to the formation of blocking zones of intense high pressure over the Atlantic Ocean that divert rain-bearing wind depressions away from the Mediterranean. This blocking may be related to the cycles of El Nino, the periodic reversal of winds and waves in the tropical Pacific Ocean. Due to the effects of toxic gases, it is assumed that year-round average temperature in southern Europe will reach 18°C by the year 2030 and rainfall will diminish by 19% to 20%. 

Figure 12.6 Vertical distributions of Group 4 elements in the North Pacific. Data sources Ti (Orians et at., 1990), Zr (McKelvey and Orians, 1993) and Hf (Godfrey et at., 1996). The Hf distribution (dotted line) was calculated based on the average Atlantic Ocean Zr/Hf ratio of Godfrey et at. (1996) and the Pacific Ocean Zr profile of McKelvey and Orians (1993).

The data from remote marine air are of particular interest because both the sulfur sources and the atmospheric oxidant fields should be fairly homogeneous. Andreae and Raemdonck (141 presented the first data showing the diurnal variations of DMS over the open ocean, from the equatorial Pacific ocean. They obtained a mean concentration of 128 ppt with a standard deviation of S3 ppt. By averaging the data into 4 hour intervals they showed a daytime minimum and nighttime maximum with a diurnal range of 90 to 149 ppt. Dividing the maximum by the minimum gives a factor of 1.65 diurnal variation for this data set. 

The whole Pacific Ocean floor contains 1.5 trillion tons of manganese nodules but the percentages of commercially useful metals are lower for the average of the total Pacific than in the radiolarian ooze area. 

Measured size distributions of salt particles are monomodal and can by parameterized by the power law, with the index varying within 0.97-4.2 (average 2.3-2.6). The density of MSA particles is close to 2.35 — 2.40 g/m The spatial distribution of Cn MSA (r > 1 pm) for different regions of the world ocean can be illustrated by the following values in the Pacific Ocean Cn = (1.2-1.5) cm in the Indian Ocean (0.9-1.0) cm" near the Australian coastline 0.4 cm near the boundaries of the Antarctic ice sheet (1.8-2.1) cm" and near the Black Sea coastline (0.32-1.93) cm" [8]. The vertical distribution of Cn MSA has some specific features. A maximum of Cn distribution is often observed at altitudes of several hundred meters (apparently, because of a decrease in the Cn MSA near the water surface, resulting from the capture of salt particles by sea waves). At altitudes 2-3 km the value of Cn MSA constitutes < 1 % of the total Cn value, which is explained by the cloud filter . However, over land, near the coastline, at an altitude of 3 km, Cn MSA is somewhat higher than at the same level over the sea surface. This is connected with a more intensive turbulence over land. In general, sea-salt aerosol particles have to be chemically composed of dried sea water 88.7% chlorides, 70.8% sulfates, 0.3% carbonates, and 0.2% other salts. 

The information on the quantities of combusted materials, and on aerosol and elemental carbon production, which is collected in Tables II-V, has been combined in Table VI to derive the state of the atmosphere during the nuclear war. We assume that the war would last for only a few days the aerosol particles would also be given off to the atmosphere in such a short time. Most fire produced aerosol would initially be located between 30°N and 60 N, where most of the nuclear targets are located. If the nuclear explosions would occur over a period of three days, the fire plumes produced on the West and East coast of the US and over Europe (including the USSR) could cover most of the 30-60°N latitude belt, except the Pacific Ocean. This is based on an average westerly wind speed of 20 m/s in tbe middle and upper troposphere (Oort and Rasmussen, 1971). Spread in South-North direction within the latitude zone should... 

Based on the data of Stallard and Edmond (1981) it can be calculated that average Amazon rainwater contains (tt moles 1 ) 12.4 Na, 1.0 K, 1.2 Mg, 1.1 Ca, 13.7 Cl, 5.1 SO4, 2.1 NO3, 0.5 NH4 and 0.0 Si. Of course there is some variability depending on location, etc. This is well seen in the case of Cl , the concentration of which declines from east to west and is negligible in upper Amazon precipitation tending to confirm the insignificance of Pacific Ocean water for Amazon precipitation. 

Only occasionally has the N content of solid phase extracts been reported. At a site in the Atlantic Ocean the carbon to nitrogen ratio (C N) of XAD 8 and XAD 2 extracts fell in the range of 40-57 (57 0.9 and 41.1 3.3, respectively DrufFel et ai, 1992). In contrast, at the same site XAD 4, when used as the second resin in series with XAD 8 or XAD 2, extracted compounds with lower C N ratios - 19—24 (21.0 2.4). These values are only slighdy higher than ratios reported for total DOM (see below). McKnight and Aiken (1998) reported a C N value of 37 for DOM extracted by XAD 8 at one site in the Pacific Ocean at other sites in the N. Pacific Ocean XAD 2 was found to extract DOM with a C N ratio between 32 and 46.5 (Druffel et al, 1992 Meyers-Schulte and Hedges, 1986). Bronk (2002, Table III) compiled various literature values and arrived at an average C N ratio of 32.8 19.5 for total humic substances isolated from a variety of aqueous environments (see McCarthy and Bronk, this volume). 

Values discussed in the previous section represent an oceanic average and individual regions and parts of the water column may behave differendy. For example, Abell et al. (2000, 2005) found that the DOM reminerahzed along isopycnals outcropping in the subtropical North Pacific Ocean is C-rich (C N 30) based on this C N ratio these authors concluded that DOM contributes between 70 and 90% of the total organic matter remineralized in the upper thermocHne. As more data are collected, other sites in the ocean may show similar variabiHty. 

Table 3.1 Average carbon (6 3C) and nitrogen (6 5 ) isotope signature of HMWDOM isolated from several different sites in the Atlantic Ocean. Pacific Ocean, and the Gulf of Mexico...

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