Ocean, elements found

Calcium is the fifth most abundant element found in the Earths crust. It is not found as a free element, but as calcium compounds (mostly salts and oxides), which are found on all landmasses of the world as limestone, marble, and chalk. Calcium, particularly as the compound calcium chloride (CaCl ), is found in the oceans to the extent of 0.15%. 

Table 5), and several are now being used, or are potentially useful, for measuring key ocean elements. The most common use of direct potentiometry (as compared with potentiometric titrations) is for measurement of pH (Culberson, 1981). Most other cation electrodes are subject to some degree of interference from other major ions. Electrodes for sodium, potassium, calcium, and magnesium have been used successfully. Copper, cadmium, and lead electrodes in seawater have been tested, with variable success. Anion-selective electrodes for chloride, bromide, fluoride, sulfate, sulfide, and silver ions have also been tested but have not yet found wide application. 

Table 1.4 shows a distribution of the major elements found in the earth s crust, the ocean water, and the human body. The composition of the human body, which is reason-... 

Hydrogen is the commonest element found in the Universe and is a major constituent of stars. It is relatively much less common on Earth but nevertheless it forms nearly 1 per cent by mass of the crust and oceans, mainly as water and in hydrates and hydroxide minerals of the crust. It is ubiquitous in biology. 

If one assumes that other elements are transported by the atmosphere from urban centers in a manner similar to that of lead, and are subsequently deposited on the ocean surface and mixed vertically at a rate similar to that of lead, then the expected increase in ocean water concentrations of other elements can be calculated (Table 4). The most probable values show increases of 30% (Table 1) for several of the elements, although higher concentrations may exist. The values of the most probable increases suggest that trace elements in the surface layers bear little relationship to the concentration of elements found in organisms. The uptake of trace elements by the marine biota, however, does depend upon the chemical state of the elements, and we shall discuss this further in the later sections. 

The list of elements found in living matter is very different from those of the Earth s crust, oceans, and atmosphere. The major elements in living organisms are shown in Table 3.2. 

TABLE 7 The Abundance of Elements Found in the Earth s Crust and Oceans that are Commonly Utilized in Electronic Assemblies (After Lyde, Ref. [16], 1999)... 

The ocean is host to a variety and quantity of inorganic raw materials equal to or surpassiag the resources of these materials available on land. Inorganic raw materials are defined here as any mineral deposit found ia the marine environment. The mineral resources are classified generally as iadustrial minerals, mineral sands, phosphorites, metalliferous oxides, metalliferous sulfides, and dissolved minerals and iaclude geothermal resources, precious corals, and some algae. The resources are mosdy unconsoHdated, consoHdated, or fluid materials which are chemically enriched ia certain elements and are found ia or upon the seabeds of the continental shelves and ocean basias. These may be classified according to the environment and form ia which they occur (Table 1) and with few exceptions are similar to traditional mineral deposits on land. 

Chlorine. Chlorine, the material used to make PVC, is the 20th most common element on earth, found virtually everywhere, in rocks, oceans, plants, animals, and human bodies. It is also essential to human life. Eree chlorine is produced geothermally within the earth, and occasionally finds its way to the earth s surface in its elemental state. More usually, however, it reacts with water vapor to form hydrochloric acid. Hydrochloric acid reacts quickly with other elements and compounds, forming stable compounds (usually chloride) such as sodium chloride (common salt), magnesium chloride, and potassium chloride, all found in large quantities in seawater. 

Oxygen occurs free in air in which it forms 21% by volume. It is also found combined with hydrogen in water and constitutes 86% of the oceans, and with other elements such as minerals constituting ca 50% of the earth s crust. In the laboratory it is usually prepared by the thermal decomposition of potassium chlorate in the presence of manganese dioxide catalyst ... 

The seventh element in order of abundance in the Earth s crust is potassium - about the same as sfjdium with similar properties. While sodium is readily available from the ocean, potassium is found and extracted from many mineral formations. About 90 percent of the potassium that is extracted goes to the production of fertilizers. Other purposes for it are ceramics and fire extinguishers for which potassium bicarbonate is better than sodium bicarbonate. 

Table 1.1 lists the names and symbols of several elements that are probably familiar to you. In either free or combined form, they are commonly found in the laboratory or in commercial products. The abundances listed measure the relative amount of each element in the earth s crust, the atmosphere, and the oceans. 

These studies introduce and utilize a natural biogeochemical tracer of sedimentary processes. The use of 210Pb to trace deep ocean currents where flocculent material is transported in one region and deposited in another may provide valuable information on deep sea transport. However, more work is required to verify these initial findings. Additional work also is needed to evaluate mechanisms responsible for the differences in diffusion of certain elements in sediments compared to lead and to identify if two types of biological mixing may indeed be responsible for the high sedimentation rates found in the deep ocean. 

In addition to the dissolved elements and compounds in the oceanic water column, a wide variety of water column chemicals are found in marine organisms and organic detritus. For example, a milliliter of surface seawater can contain on the order of 10 million viruses, 1 million bacteria, 100,000 phytoplankton, and 10,000 zooplankton [9]. With the advent of soft ionization processes for mass spectrometry systems, scientists have been able to study these marine organisms at molecular level. The use of electrospray ionization (ESI see Section 2.1.15), atmospheric pressure chemical ionization... 

Broecker and Li (1970) and Broecker (1974) found that the 14C/12C ratio in the deep ocean was 84 percent of this ratio in the pre-bomb surface ocean. Assuming that surface carbon (dissolved and falling debris) is the only source of deep ocean carbon, calculate the residence time tc of this element in the deep-ocean. The 14C decay constant is 1.2 x 10 4a 1. 

Mantle composition can also be assessed through examination of lavas from other oceanic settings. In a study of well-characterized Hawaiian lavas, Chan and Frey (2003) found a total range indH i that overlaps the range for MORE, +2.5 to +5.7. Other data from Kilauea volcano substantiate this range (Tomascak et al. 1999b). The Hawaii data, when compared with other isotopic and elemental parameters, suggested incorporation of recycled altered oceanic crust into the source of the Hawaiian plume (Chan and Frey 2003). 

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