Seawater composition table

The use of synthetic media is preferable to natural filtered and/or sterilised media, as trace substances are expensive to remove from natural waters. In addition to this, the reproducibility of assays is improved if synthetic media are used. Different artificial seawater compositions have been used in toxicity testing. From the media investigated by our group, (see Table 7.1.2) the ASTM substitute ocean water [66] gave the best results for growing microalgae. 

Table I shows the composition of some natural seawaters around the world. This wide seawater composition variation affects the quality of the product, i. e. the product salinity. This, of course, in the unlikely case that all we had to contend with in the RO conversion were the composition variations. In fact, the other variables such as the number and the nature of microorganisms, the amount, size, and nature of suspended solids and their variability, presence or absence of pollutants, each and all of which can be affected by the prevailing atmospheric condltionspresent, are much more consequential to trouble-free operations than the seawater composition variations.

The oceans at this time can be thought of as the solution resulting from an acid leach of basaltic rocks, and because the neutralization of the volatile acid gases was not restricted primarily to land areas as it is today, much of this alteration may have occurred by submarine processes. The atmosphere at the time was oxygen deficient anaerobic depositional environments with internal CO2 pressures of about 10-2-5 atmospheres were prevalent, and the atmosphere itself may have had a CO2 pressure near lO-25 atmospheres. If so, the pH of early ocean water was lower than that of modern seawater, the calcium concentration was higher, and early global ocean water was probably saturated with respect to amorphous silica (—120 ppm). Hydrogen peroxide may have been an important oxidant and formaldehyde, an important reductant in rain water at this time (Holland et al., 1986). Table 10.5 is one estimate of seawater composition at this time. 

Table 10.5. An example of early seawater composition. (After Garrels and Perry,...

Table 4.6. Change in Seawater Composition Resulting from the Doubling of Atmospheric CO2 (compare Figure 15.17)...

The bulk chemical composition of seawater DOM (Table 8.8), however, is not consistent with a predominant riverine origin. In particular, seawater DOM is depleted in C and enriched in C and compared with most DOM discharged by rivers (with the Amazon being taken here as an example). Seawater DOM is also depleted in aromatic carbon (as measured by C NMR) and lignin phenol structural units (as determined by CuO oxidation), possibly as a consequence both of the low phenol content of marine plankton, and of selective alteration of aromatic carbon by photodegradation. Thus all evidence to date, including elevated total concentrations in surface marine waters (Fig. 8.19), indicates that seawater DOM is largely... 

Atmospheres are usually classified subjectively (Table 2.1) as industrial, urban, or rural, with the classification usually corresponding to high, medium, or low sulfur dioxide, respectively. The numerical value relates both to the geographical area considered and the year environmental controls worldwide are leading to diminution in the amount of sulfur dioxide in the air. A fourth category, marine or coastal, reflects the presence of chlorides from the sea and should be subdivided into tropical and temperate areas (because of the difference in seawater composition and temperature) as well as industrial, urban, or rural. 

Generalised conclusions can be based on salt content levels of approx. 35 g/kg and a chloride ion content of 19 g/kg. An assumed total salt content (or salinity) of 35 g/kg (3.5%) results in the seawater composition shown in Table 3 [2, 3]. 

There is a large variation in the total dissolved solid contents (TDS) from one ocean to another. The total dissolved solid content in the Baltic Sea is represented to be on an average of 8000 ppm as against the TDS content of 44000-60000 ppm in Arabian Gulf water. The degree of corrosivity of seawater varies with the TDS content. The chloride ion is the most aggressive (corrosive) constituent in seawater, as it has a tendency to penetrate the passive films on the metal surface and destroy them. A typical seawater composition is shown in Table 9.4. 

The source of the Dead Sea s mineral content, and especially the calcium chloride, is somewhat uncertain. Its composition (Table 2.8) is very similar to a seawater dolomitization brine (from potash end liquor) that has had only limited... 

Table 17-1 Composition and average concentrations of chemicals in seawater and Rhine River water (Duisburg)...

Seawater muds are commonly used on offshore locations, which eliminate the necessity of transporting large quantities of freshwater to the drilling location. The other advantage of seawater muds is their inhibition to the hydration and dispersion of clays, because of the salt concentration in seawater. The typical composition of seawater is presented in Table 4-48 most of the hardness of seawater is due to magnesium. 

MacKenzie and Carrels (1966) approached this problem by constructing a model based on a river balance. They first calculated the mass of ions added to the ocean by rivers over 10 years. This time period was chosen because geologic evidence suggests that the chemical composition of seawater has remained constant over that period. They assumed that the river input is balanced only by sediment removal. The results of this balance are shown in Table 10-13. 

Several workers have intended to estimate the chemical compositions of Kuroko ore fluids based on the chemical equilibrium model (Sato, 1973 Kajiwara, 1973 Ichikuni, 1975 Shikazono, 1976 Ohmoto et al., 1983) and computer simulation of the changes in mineralogy and chemical composition of hydrothermal solution during seawater-rock interaction. Although the calculated results (Tables 1.5 and 1.6) are different, they all show that the Kuroko ore fluids have the chemical features (1 )-(4) mentioned above. 

During the last two decades, many experimental studies on the seawater-rock interaction at elevated temperatures (100-400°C) have been conducted. Particularly, detailed seawater-basalt interaction experiments have been done. Several experimental studies on seawater-rhyolite interaction and seawater-sedimentary rock interaction are also available (Bischoff et al., 1981). Examples of chemical compositions of modified seawater experimentally interacted with various kinds of rocks are shown in Table 1.9. 

Isotopic compositions of minerals and fluid inclusions can be used to estimate those of Kuroko ore fluids. Estimated isotopic compositions of Kuroko ore fluids are given in Table 1.10. All these data indicate that the isotopic compositions lie between seawater value and igneous value. For instance, Sr/ Sr of ore fluids responsible for barite and anhydrite precipitations is 0.7069-0.7087, and 0.7082-0.7087, respectively which are between present-day. seawater value (0.7091) and igneous value (0.704-0.705). From these data, Shikazono et al. (1983), Farrell and Holland (1983) and Kusakabe and Chiba (1983) thought that barite and anhydrite precipitated by the mixing of hydrothermal solution with low Sr/ Sr and seawater with high Sr/ Sr. 

The average composition of seawater is shown in Table 1-3. Seawater muds have sodium chloride concentrations above 10,000 ppm. Most of the hardness in seawater is caused by magnesium. 

For a first chemical model, we calculate the distribution of species in surface seawater, a problem first undertaken by Garrels and Thompson (1962 see also Thompson, 1992). We base our calculation on the major element composition of seawater (Table 6.2), as determined by chemical analysis. To set pH, we assume equilibrium with CO2 in the atmosphere (Table 6.3). Since the program will determine the HCOJ and water activities, setting the CO2 fugacity (about equal to partial pressure) fixes pH according to the reaction,... 

Table 6.2. Major element composition of seawater (Drever, 1988)...

We turn our attention now to the hydrothermal brines of the Red Sea. An oceanic survey in 1963 discovered pools of hot, saline, and metal-rich brines along the axial rift of the Red Sea (Degens and Ross, 1969 Hoffmann, 1991). The dense brines pond in the rift s depressions, or deeps. The Atlantis II deep contains the largest pool, which measures 5 x 14 km and holds about 5 km3 of supersaline brine. The deep holds two layers of brine. The lower brine contains about 25 wt.% dissolved salts and exists at temperatures up to 60 °C. Table 6.8 shows the brine s average composition. A somewhat cooler, less saline water overlies the lower brine, separating it from normal seawater. 

Table 22.3. Endmember compositions of a hydrothermal fluid and seawater, East Pacific Rise near 21 °N (Von Damm et al., 1985 Drever, 1988 Mottl and...

Table 30.1 shows the compositions of formation waters from three North Sea oil fields, and the composition of seawater (from Drever, 1988). The origin of the scaling problem is clear. Seawater contains more than 2500 mg kg-1 of sulfate but... 

Table 30.1. Compositions offormation fluids from three North Sea oilfields (Edward Warren, personal communication) and seawater...

Fig. 30.1. Volumes of minerals precipitated during a reaction model simulating the mixing at reservoir temperature of seawater into formation fluids from the Miller, Forties, and Amethyst oil fields in the North Sea. The reservoir temperatures and compositions of the formation fluids are given in Table 30.1. The initial extent of the system in each case is 1 kg of solvent water. Not shown for the Amethyst results are small volumes of strontianite, barite, and dolomite that form during mixing.

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