Open ocean

This removal may also include diffusion of soluble U(VI) from seawater into the sediment via pore water. Uranium-organic matter complexes are also prevalent in the marine environment. Organically bound uranium was found to make up to 20% of the dissolved U concentration in the open ocean." ° Uranium may also be enriched in estuarine colloids and in suspended organic matter within the surface ocean. " Scott" and Maeda and Windom" have suggested the possibility that humic acids can efficiently scavenge uranium in low salinity regions of some estuaries. Finally, sedimentary organic matter can also efficiently complex or adsorb uranium and other radionuclides. 

If uranium is internally cycled in coastal environments or if the riverine delivery of U shows some variability, residence time estimates (regardless of their precision) cannot be sensitive indicators of oceanic uranium reactivity. Based on very precise measurements of dissolved uranium in the open ocean, Chen et alJ concluded that uranium may be somewhat more reactive in marine environments than previously inferred. Furthermore, recent studies in high-energy coastal environments " indicate that uranium may be actively cycled and repartitioned (non-conservative) from one phase to the next. 

Wave size is determined by wind speed and fetch, the distance over the oceans surface which the wind travels. Favorable wind energy sites are generally western coastlines facing the open ocean such as the Pacific Coast of North America and the Atlantic Coast of Northern Europe. Norway, Denmark, Japan, and the United Kingdom are the world leaders in wave energy technologies. 

Although the relationship of sediment adsorption to water concentration appears to be a controlling feature of shallow water systems such as lakes and coastal shelf water, the open ocean is more likely to contain soluble plutonium which seems to be unaffected by particulate matter. This is particularly evident in two oceanographic studies. Bowen et al have discovered a stratum of plutonium in the North Pacific at about 500m that has not changed depth appreciably from 1973 to 1980. How it arrived at this depth is subject to conjecture but it appears to be soluble plutonium which is not settling(17). Fukai et al have delineated plutonium maxima in the Mediterranean Sea which seem to be due to soluble species(18). Comparison of americium to plutonium ratios in this... 

Observations of the ratio of oxidized plutonium to reduced plutonium may provide some insight to the observations of erratic formation and lack of equilibration in laboratory solutions at ORNL versus fairly consistent and predictable behavior in oligo-trophic lakes and marine systems. In coastal water and the relatively shallow Lake Michigan, Pu(V) is about 90 percent of the soluble plutonium, but in the upper waters of the open ocean, where it does not interact with the seafloor due to the depths,... 

Over the past decade, plastic debris has become a common feature of beaches and coastal waters adjoining populated areas of Europe (36-38), the Mediterranean (39-41), North and Central America (42-44) and New Zealand (45). Plastics are also present in the open ocean both near the major shipping lanes and in the most remote regions of the world (the Arctic (46), the Benguela Current (47), the Cape Basin area of the South Atlantic (48), the Humboldt Current in the South Pacific (49), and the Antarctic (50, 51). 

The /-ratio typically varies from values as low as 0.03 to 0.30 in the open ocean (e.g., McCarthy et al., 1996) to values greater than 0.80 in the coastal ocean (Platt and Harrison, 1985). 

Over 20% of the world s open ocean surface waters are replete in light and major nutrients (nitrate, phosphate, and silicate), yet chlorophyll and productivity values remain low. These so-called "high-nitrate low-chlorophyll" or HNLC regimes (Chisholm and Morel, 1991) include the sub-arctic North Pacific (Martin and Fitzwater, 1988 Martin et al, 1989 Miller et al, 1991), the equatorial Pacific (Murray et al, 1994 Fitzwater et al, 1996) and the southern Ocean (Martin et al.,... 

Sediment trap studies in the open ocean show that the flux of organic carbon at any depth is directly proportional to the rate of primary productivity in the surface water and inversely proportional to the depth of the water column (Suess, 1980) ... 

Emerson, S., Quay, P., Karl, D. et al. (1997). Experimental determination of the organic carbon flux from open-ocean surface waters. Nature 389, 951-954. 

The concentration of trichloroethylene in the open oceans may be an indication of the environmental background levels in water. Levels in open waters of the Gulf of Mexico were below the detection level of 1 ppt (Sauer 1981). Average levels of 7 ng/L (7 ppt) and 0.3 ppt were found in the northeastern Atlantic (Murray and Riley 1973) and in Liverpool Bay (Pearson and McConnell 1975), respectively. 

Sauer TC Jr. 1981. Volatile organic compounds in open ocean and coastal surface waters. Organic Geochem 3 91-101. 

Seawater, rainwater, river water, estuarine water, open ocean water, fresh water, ground water, drinking water... 

National Research Coundl Canada (1992) Certified Reference Material NASS-4 Open Ocean Seawater Reference Material for Trace Metals. National Research Council of Canada. Ottawa. National Research Council Canada (1995) Certified Reference Material CARP-i Groimd Whole Carp Reference Material for Organochlorine Compounds. National Research Council of Canada, Ottawa. 

Kn TL, Knanss KG, Mathien GG (1977) Uraninm in the open ocean Concentration and isotopic composition. Deep-sea Res 24 1005-1017... 

Muhs DR, Kermedy G, Rockwell TK (1994) Uranitun-series ages of marine terrace corals from the Pacific coast of North America and implications for last-interglacial sea level history. Qrrat Res 42 72-87 Nozaki Y, Nakanishi T (1985) Pa and °Th profiles in the open ocean water coltrrrm. Deep-Sea Res 32 1209-1220... 

Chung Y, Finkel R, Bacon MP, Cochran JK, Krishnaswami S (1983) Intercomparison of °Pb measurements at GEOSECS station 500 in the northeast Pacific. Earth Planet Sci Lett 65 393-405 Chung Y, Finkel R (1988) Po-210 in the Western Indian-ocean - distributions, disequilibria and partitioning between the dissolved and particulate phases. Earth Planet Sci Lett 88 232-240 Clegg SL, Whitfield M (1991) A generalized model for the scavenging of trace metals in the open ocean -... 

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