Seasonal variability seawater

Variability of Seawater Vertical sections through seawater showing the distribution of temperature, salinity, and oxygen for the Pacific Ocean and Western Atlantic Ocean are shown in Figures 21.3 and 21.4. The global variability of natural seawater and its effects on corrosion have been reviewed in particular with respect to seasonal variation of temperature, salinity, oxygen and pH in the Pacific surface water. Data is also given on... 

First I set the variable prod = fuel. This amounts to a seasonally varying biological productivity, which varies between 1 and — 1 moles of carbon per cubic meter per year. I start the calculation at 1 year, with the initial values equal to the seawater values, and run it out to a time of 10 years. 

Seawater is a unique environment that cannot be duplicated in the laboratory. Throughout the world, seawater can vary widely in terms of its specific chemical composition, oxygen content, temperature, salinity, pH, and biological activity. At a given location, seawater is also prone to v uia-tions from seasonal influences. All of these variables, combined with the long-term time dependence of many metal reactions, will affect the corrosion occurring on metals and alloys in seawater. In addition, the composition of corrosion products and of calcareous deposits formed under cathodic polarization conditions will influence metal corrosion. 

Mercury has been found in seawater in a variety of operationally characterized particulate (> 0.4 or > 0.45 jum) and dissolved ( ionic , colloidal , gaseous , reactive , easily reducible , labile , organically associated , non-reactive ) forms. In addition, chemically defined species have been determined, such as elemental (H, monomethyl- (MMHg) and dimethylmercury (DMHg) Bloom et aL, 1995 Coquery and Cossa, 1995 Iverfeldt, 1988 Leermakers et al, 1995 Mason et aL, 1995). The relationship between the different species of Hg and its total concentration (Hgx) is highly variable in space (with sea area and water depth) and time (daily and seasonal changes). The procedure described here applies to the determination of total mercury . A brief outline, however, is also given on the determination of some of the major species for which more or less standardized methods are in common use. 

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