Element in ocean

Murray, J.W. (1987), "Mechanisms controlling the distribution of trace elements in oceans and lakes", in R.A. Hites and S.J. Eisenreich, Eds., Sources and Fates of Aquatic Pollutants, Adv. Chem. Ser. 216. 

The geochemical fate of most reactive substances (trace metals, pollutants) is controlled by the reaction of solutes with solid surfaces. Simple chemical models for the residence time of reactive elements in oceans, lakes, sediment, and soil systems are based on the partitioning of chemical species between the aqueous solution and the particle surface. The rates of processes involved in precipitation (heterogeneous nucleation, crystal growth) and dissolution of mineral phases, of importance in the weathering of rocks, in the formation of soils, and sediment diagenesis, are critically dependent on surface species and their structural identity. 

Recent reviews on chemical speciation are published by e.g. Stumm and Brauner (1975), Florence and Batley (1980) and Leppard (1983) sometimes, with special reference to metal-organic interactions (Mantoura, 1982) or complexation in natural waters (Kramer and Duinker, 1984b). Bruland (1983) summarized the distribution and behaviour of trace elements in ocean waters. The occurrence of certain species is largely dependent on the environmental conditions. There exists a strong competition of trace metals with H+ or major cations like Ca2+ and Mg2+ in seawater, but also with other trace metals which might form more stable complexes with the ligand in question on the other side, many potential ligands or chelators compete for one trace element. 

Radioactive Elements in Ocean Waters and Sediments. In Paul, H. Nuclear Geology, S. 115—120, 329—331. New York J. Wiley Sons, 1957. 

Hertogen J., Janssens M. J., and Palme H. (1980) Trace elements in ocean ridge basalt glasses implications for fractionations during mantle evolution and petrogenesis. Geochim. Cosmochim. Acta 44, 2125-2143. 

Martin J.-M. and Windom H. L. (1991) Present and future roles of ocean margins in regulating marine biogeochem-ical cycles of trace elements. In Ocean Margin Process in Global Change (eds. R. F. C. Mantoura, J.-M. Martin, and R. Wollast). Wiley-Interscience, New York, pp. 45-67. 

Within this chapter, we focus on four elements (C, O, N, S), which participate in most marine geochemical reactions and which are important elements in the biological system. Some recent developments in the use of B isotopes are added to this chapter. We summarize the influence of geochemical processes on the stable isotope distribution of those elements in ocean water and marine sediments. After a short review on the fundamentals of stable isotope fractionation and mass spectrometry, the most important fractionation mechanisms for each el-... 

The dissolved concentrations of the 25 selected elements in ocean deep water are controlled by natural processes. This is not principally the case for river water and rain. The data on river water listed in Table 1.2 (according to Turekian 1969 Wedepohl 1969-1978 and Martin and Mey-beck 1979) are mainly from rivers without major contamination from industrialized areas. Suspended clay materials in the rivers have a high capacity to adsorb organic residues and metals from anthropogenic and natural sources (sewage, industrial immissions, soil extraction by acid rain water, etc.), and in this way they keep the level of dissolved metals reasonably low. 

Over the past 60 years refined techniques of analysis have shown the patterns of distribution of the trace elements in ocean water profiles in all the oceans. These results are summarized by the late Yoshiyuki Nozaki in this volume. Similarly the understanding of the stable isotopes of oxygen, carbon and nitrogen in the oceans have played important roles in deciphering both the ancient temperature history of the oceans and the biological pathways of nutrient elements in the marine system. 

Bougault H., Joron J.L. and Treuil M., 1980, The primordial chondritic nature and large-scale heterogeneities in the mantle evidence from high and low partition coeflicienc elements in oceanic basalts. Phil Tram. R. Soc. Land., A 297, 203-213. 

Kay R.W. and Hubbard N.J., 1978, Trace elements in ocean ridge basalts. Earth Planet. Sci. Lett., 38, 95-116. 

Table 12-1. Concentrations and distribution types of the trace elements in ocean waters (according to Donat and Bruland, 1995).

On this basis, Bowen states that only in the case of the elements, chromium, copper, lead and tin, would the mean concentration in fresh water rise significantly, while the change in concentration of all elements in ocean water would be immeasurably small. Of these four elements, copper is asserted to be potentially the most dangerous, since the dissolution of the world output of copper in the total mass of fresh water would raise its concentration above the toxic limit for some algae. Mercury must also be considered as a candidate for the distinction of being the most hazardous metal pollutant of the hydrosphere, since it is highly toxic and the amount produced annually is greater than the amount added to the ocean in fresh water (Table 40). 

If we compare the total amounts of trace elements present in solution in sea water with the annual levels of production (Table 40), it is clear that the total dissolution of the global annual production of most elements would have a negligible effect on their concentrations in the ocean. With the notable exception of the element lead, it would require the dissolution of over one hundred years production of every element to double its present concentration in sea water. For some elements like boron, fluorine, molybdenum and nickel, this level of enhancement would require the dissolution in the ocean of thousands of years of production at present levels. This is to say that any significant enhancement of the levels of these elements in ocean water as a result of human activity is impossible. 

While the possibility that the overall trace-element composition of the ocean will ever be significantly affected by any of man s industrial activity seems remote, the wisdom of bringing about even slight temporary increases in the content of potentially toxic non-essential trace elements in ocean water can certainly be called in question, and there is no doubt that pollution problems frequently arise before dispersion becomes effective. 

A main feature of the lanthanide distribution in these materials is a substantial depletion in Ce. Excess Ce is found in authigenic ferromanganese nodules (e.g., Goldberg et al., 1963 Ehrlich, 1968 Glasby, 1972-73). Presumably, the selective uptake of Ce by these common oceanic materials accounts for the relative deficiency of that element in ocean water. Concentrations of lanthanides in most biogenic and authigenic oceanic materials are relatively low, and the proportions of those materials in common ocean sediments are low, so their relative abundance distributions do not appreciably affect the overall abundances for the sediments that contain them. 

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