Seawater salinity evaporation effects

In the solar evaporation ponds, salinities in the cores reached almost four times oceanic values. In these cores the concentration profile of bimane sulfide with depth also tracked that of methylene blue sulfide and bimane total reduced sulfur tracked DTNB. However, the difference between the bimane method and the other two methods is unacceptably large and suggests that there was some inhibition of the bimane reaction. Pore water samples which were diluted to normal seawater salinity with 200 mM HEPES buffer pH 8 were not inhibited. Dilution will of course lead to a loss of sensitivity for trace thiols. Another factor which can effect the yield of the bimane reaction is the unusual... 

To model the chemical effects of evaporation, we construct a reaction path in which H2O is removed from a solution, thereby progressively concentrating the solutes. We also must account in the model for the exchange of gases such as CO2 and O2 between fluid and atmosphere. In this chapter we construct simulations of this sort, modeling the chemical evolution of water from saline alkaline lakes and the reactions that occur as seawater evaporates to desiccation. 

However, salinity values are easily obtained with a salinometer (which measures electrical conductivity and is appropriately calibrated with standard solutions and adjusted to account for T effects). The salinity of seawater increases if the loss of H2O (evaporation, formation of ice) exceeds the atmospheric input (rain plus rivers), and diminishes near deltas and lagoons. Salinity and temperature concur antithetically to define the density of seawater. The surface temperature of the sea reflects primarily the latitude and season of sampling. The vertical thermal profile defines three zones surface (10-100 m), where T is practically constant thermoclinal (100-1000 m), where T diminishes regularly with depth and abyssal... 

To within a few percent, conservative elements in seawater have constant concentration salinity ratios. That is, their concentrations are not greatly affected by processes other than precipitation and evaporation the same processes that control salinity in the ocean. This definition is of course operational since the ability to determine the effect of biological and chemical processes on concentration depends on the accuracy and precision of the measurement method. Elements of high concentration tend to be conservative because they are relatively unreactive however, conservative elements are present in all concentration ranges because some of them are both low in crustal abundance and relatively unreactive. There are of course... 

The isotope effects (both kinetic and equilibrium) that deplete deuterium, D, and 0 in evaporated water vapor must enrich these isotopes in the surface seawater left behind. This isotope effect can be seen in longitudinal transects of surface waters in both the Atlantic and Pacific Oceans (Fig. 5.12), which indicate a broad maximum of between roughly 30° north and south latitudes. Salinity maxima are evident over the same latitude band, with a slight minimum near the Equator. The parallel maxima in and salinity result because net evaporation from warm surface waters at lower latitudes preferentially leaves behind both H2 0 molecules and salt. Rainfall in excess of evaporation from atmospheric convection cells rising near the Equator is recorded by both a salinity and a minimum. 

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