Ocean open waters

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.,... 

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. 

The oceanic distribution of cobalt is similar to that of manganese, although cobalt concentrations are 10-100 times smaller maximum concentrations are 100-300 pM in surface waters, decreasing to 10 pM at depths below 1000 m. As concentrations of cobalt in seawater are so low, it may become biolimiting in open ocean surface waters. 

One with concentrations of metals corresponding to open-ocean surface water with an information value for total iron concentration. 

Nutrient calibration solutions in seawater are commonly prepared by dissolving known amounts of pre-dried, solid, primary standard salts in low-nutrient seawater. Low-nutrient seawater must be collected from oligotrophic open-ocean surface water to minimize background nutrient... 

In the open ocean, surfece water salinities exhibit meridional gradients largely controlled by the local balance between water loss through evaporation and water gain through... 

The sediment oxygen penetration depth as a function of water coiumn depth in the Atlantic Ocean (open symbols) and Pacific Ocean (closed symbols). Source-. From Martin, W. R., and F. L. Sayles (2003). Treatise on Geochemistry, Elsevier. 

Idealized depth profiles of redox species in (a) open-ocean sediments (water depth >1000m) and (b) coastal sediments (water depth <1000 m). 

Note that for the total (dissolved and particulate) concentration, Ct, the abrupt change of the solid-to-water-phase ratio, rsw (Eq. 9-15), at the sediment surface acts like a phase change. The numerical example given in Table 19.1 demonstrates that the transition from the open water column of a lake or the ocean to the sediments involves an increase of rsw by 5 to 6 orders of magnitude. Typically, in the open water, rs p is of order 10 3 kg m-3 while in the sediment column lies between 102 and 103 kg nr3. Thus, at equilibrium the total (dissolved and sorbed) concentration per unit bulk volume on either side of the interface for compounds with small to moderate solid-water distribution ratios (Ki <10 m3kg ) is approximatively given by (see Box 19.1, Eq. 4) ... 

Fuck ice is icc covering more than half the visible sea surface no open water whatever is visible in unbroken pack ice. such as that which sometimes covers the central Arctic Ocean. 

Emulsification. This is a water-in-oil process in which water is incorporated into the floating oil. Such emulsions, which may contain from 20 to 80% water, are often very viscous and referred to as mousse. Mousse formation is highly dependent on oil composition. High levels of asphalt-type compounds, as well as waxes, appear to promote the formation of these emulsions. Ocean turbulence also accelerates mousse formation, although a fully developed, stable emulsion may be formed from some oils under relatively quiescent open-water conditions. Early treatment of spilled oil with chemical dispersants is an excellent way to prevent emulsification. 

This is reflected in the complexation capacity. Usually a high organic matter content of river and estuarine waters will, together with the colloids in the "dissolved" fraction, result in a high CCqu (100 - 500 nM Cu2+), Fig. 7a. Coastal waters (Fig. 7b), as a result of mixing with seawater, have a lower CCcu (60 - 150 nM Cu2+). Open ocean surface waters of the North Atlantic have a CC u of 20 - 70 nM Cu2+, which in case of low in situ biological activity might be well below this value (Fig. 7c). 

We hypothesized that the input of terrestrial organic matter relative to the input of autochthonous carbon would be a good predictor of the relative importance of heterotrophic organic N formation in different aquatic systems. Following a flow path from streams to lakes to rivers to estuaries to oceans, this hypothesis would suggest that microbial organic N formation would be highest in wooded streams and rivers, moderate in lakes and estuaries, and lowest in open-water marine systems. 

Compared with the open water of the Arctic Ocean, the shelf seas of the Russian Arctic are more heavily contaminated. 

Garside, C. (1985). The vertical distribution of nitrate in open ocean surface water. Deep Sea Res. 132, 723-732. 

Figure 13-13 Nitrogen budget for the North Atlantic, modified from Galloway et al. (1996), demonstrating the m or fluxes (xlO mol year ) across the boundaries of the hasin as well as sinks (denitrification) and new sources (nitrogen fixation nitrogen deposition (N dep.)) of reactive N. Fluxes into the m or physical realms of the North Atlantic (open ocean, shelf waters, and estuaries) are highlighted hy diagonal-line fills loss terms and exchange fluxes between realms are indicated by open arrows.

Nitrogen exists in the ocean at oxidation states from -3 to +5. There are three forms of fixed inorganic N NOs", N02 and NH4+. Nitrate is the final oxidation product and is the dominant form of fixed N in the deep ocean. Nitrite generally occurs at very low concentrations because it is an intermediate in the processes of nitrification (NH4+ —> N02 —> NOs") and denitrification (N03 —> N02 —> NO —> N2O —> N2) and so seldom accumulates to a large degree. Concentrations of NH4+ are highly variable but tend to be near the limit of detection in open ocean surface waters. Each of the inorganic forms has a number of manual and automated methods of analysis. We discuss the most widely used below. 

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