Average composition of seawater

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. 

Figure 16. Depth profiles from three ODP Sites, showing Li isotopic composition variations in pore waters (open symbols) and associated sediments (filled symbols), (a) Site 918, Irminger Basin, north Atlantic (Zhang et al. 1998) (b) Site 1038, Escanaba Trough, northeastern Pacific (James et al. 1999) (c) site 1039, Middle American Trench off of Costa Rica (Chan and Kastner 2000). The average composition of seawater is noted on each profile with dashed line (note different scales). Whereas sediments have relatively monotonous compositions, pore waters have compositions reflecting different origins and processes in each site. Interpretations of the data are summarized in the text under, Marine pore fluid-mineral processes. ...

Figure 19. Plot of Li isotopic composition vs. inverse Li concentration for lakes and basinal/oilfield brines. Lakes open circle = major global lakes (Chan and Edmond 1988 Falkner et al. 1997) semi-open circle = western U.S. closed basin lakes (Tomascak et al. 2003). Oilfield brines inverted triangle = Williston basin, Saskatchewan (Bottomley et al. 2003) diamond = Israeli oilfields (Chan et al. 2002d). Mine waters (Canadian Shield basinal brines) square = Yellowknife, NWT (Bottomley et al. 1999) triangle = Sudbury, Ontario, area (Bottomley et al. 2003) star = Thompson, Manitoba, area (Bottomley et al. 2003). Average composition of seawater is included for reference.

Average composition of seawater (major ionic species) (35 ppt) [64,65]... 

It has been estimated that the oceans cover about 70% of the earth s area and contain about 80% of the water on or in the earth. Seawater concentration varies from 25,000 mg/E of total dissolved solids up to over 50,000 mg/E in the Arabian Gulf. The average composition of seawater is about 35,000 mg/E with the major ions being shown in Table 4.9. 

Table 3 Average composition of seawater at a salt content level of 3.5% [2, 3]...

Fig. 4.3. (A) Composite multispecies benthic foraminiferal Mg/Ca records from three deep-sea sites DSDP Site 573, ODP Site 926, and ODP Site 689. (B) Species-adjusted Mg/Ca data. Error bars represent standard deviations of the means where more than one species was present in a sample. The smoothed curve through the data represents a 15% weighted average. (C) Mg temperature record obtained by applying a Mg calibration to the record in (B). Broken line indicates temperatures calculated from the record assuming an ice-free world. Blue areas indicate periods of substantial ice-sheet growth determined from the S 0 record in conjunction with the Mg temperature. (D) Cenozoic composite benthic foraminiferal S 0 record based on Atlantic cores and normalized to Cibicidoides spp. Vertical dashed line indicates probable existence of ice sheets as estimated by (2). 3w, seawater S 0. (E) Estimated variation in 8 0 composition of seawater, a measure of global ice volume, calculated by substituting Mg temperatures and benthic 8 0 data into the 8 0 paleotemperature equation (Lear et al., 2000).

Table 18.1 Average Compositions of the Earth s Upper Continental Crust, Shale, Iron-Manganese Oxides, Phosphorite, and Various Types of Marine Sediments (All in Units of ppm. Unless Noted otherwise), along with Seawater and a Hydrothermal Vent Solution from the East Pacific Rise (both in Units of 10 g L ). 

IP LLE methods are generally employed for the extraction of LASs from river waters and the solvent sublation method of Wickbold is still used for their extraction from seawater [85]. SPE methods making use of C18 and C8 phases are largely employed [85]. The amount of sorbent is optimized as a function of the degree of pollution and the average composition of river waters [85]. The performances of C18 disks and C18 cartridges are compared [85]. 

The average elemental composition of seawater is shown in Table 1 [6]. The elements which exist at more than l/igml 1 are the major elements, and those less than l/rgml-1 are the trace elements. Of these, only twelve elements are present at a concentration greater than 1/igml-1, and most other elements range from 0.5 pg ml-1 to much less than 1 ng ml-1 in content. 

Table 2 Average compositions of the Earth s upper continental crust, shale, marine sediments (all in units of ppm, noted otherwise), along with seawater and hydrothermal vent solution from the East Pacific Rise (both in...

Irreversible reaction paths (dotted and dashed lines are shown in the diagram for the hydrolysis of albite (ABCDEF) and coexisting K-feldspar and albite with relative reaction rates of 1 1 (A b c d e f g h i ) and 0.1 1 (A b"c"d"e"f, weathering of Sierra Nevada rocks (GH), and reaction of clay minerals with Bermuda seawater (IJ. The area labeled M designates the composition of surface seawater and point N represents the average composition of world streams. 

A synopsis of presently known average organic composition of seawater, after Williams (1975)... 

Seamater The isotopic composition of seawater can be understood in terms of the residence time of an element in seawater. This is the average time an element remains in seawater and is defined by the expresion... 

The compositions of seawater and average river water with respect to major solution species are given in Table III with concentration in molarity (M). The composition of seawater appears to have changed little since mid-Precambrian time, about 2 x 10 years ago, although the pH may have varied slightly. The principal factor regulating the concentrations of the major... 

TABLE III Compositions of Seawater and Average River Water, in Molarity (M)... 

So speciation allows us to determine the concentrations and activities of all known species in any chemically analyzed solution. Applied to seawater, it allows us to determine the lAP of calcite and of many other minerals. This is now done routinely on oceanographic research vessels, and a certain amount of variability is found in the composition of seawater from various locations. However, the composition of average seawater is quite well known and is... 

Input of river water to seawater is the most important process controlling chemical composition of seawater. Chemical composition of river water varies widely (Table 4.4). Thus, it is difficult to estimate average chemical composition of river water in the world. However, it can be regarded as average chemical composition of major river water in continent (Missippi, Naile, Yangtze river etc.). Chemical composition of major river water is determined by water-rock interaction, mixing... 

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