Seawater salinity effect

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... 

It was also observed that the compaction did not stop in the waterflooded areas, even though the reservoir was repressurized to the initial condition. Thus, seawater appeared to have a special interaction with chaUc at high temperatures, which has an impact on oil recovery and rock mechanics (Austad et ah, 2008). Austad and his coworkers started to work on the issues related to seawater flooding in carbonate reservoirs in 1990s. In the next section, the salinity effect on oil recovery is briefly summarized. 

In the 1990s, the thmst of surfactant flooding work has been to develop surfactants which provide low interfacial tensions in saline media, particularly seawater require less cosurfactant are effective at low concentrations and exhibit lower adsorption on rock. Nonionic surfactants such as alcohol ethoxylates, alkylphenol ethoxylates (215) and propoxylates (216), and alcohol propoxylates (216) have been evaluated for this appHcation. More recently, anionic surfactants have been used (216—230). 

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... 

Most of the published evidence suggests that marine fouling cover— particularly where it is continuous and well established — reduces corrosion rates of steels . Indeed, 35%o seawater is by no means the most corrosive of saline environments towards steel. Brackish water, as found in estuarine or certain other coastal areas, is considerably more aggressive towards steel, and careful design measures should be taken to ensure that effective corrosion control is achieved in such circumstances. 

Temperature is of particular importance to the performance of anodes, especially when anodes are buried. Anodes may often be used to protect pipelines containing hot products. Thus temperature effects must be considered. Figure 10.14 illustrates the effect of temperature on different anodes in hot saline mud. Al-Zn-In anodes experience greatly reduced capacity in open seawater at temperatures above 70°C (down to 1200Ah/kg at 100°C) and in seabed muds in excess of (900 Ah/kg at 80°C). At... 

A commonly used procedure for the determination of phosphate in seawater and estuarine waters involves the formation of the molybdenum blue complex at 35-40 °C in an autoanalyser, and spectrophotometric evaluation of the colour produced [3]. Unfortunately, when applied to seawater samples, depending on the chloride content of the sample, peak distortion or even negative peaks occur which make it impossible to obtain reliable phosphate values. This effect can be overcome by the replacement of the distilled water used in such methods by a solution of sodium chloride of appropriate concentration related to the chloride concentration of the sample. The chloride content of the wash solution need not be exactly equal to that of the sample. For chloride contents in a sample up to 18 000 mg/1, (i.e., seawater), the chloride concentration in the wash should b e within 15% of that in the sample. The use of saline standards is optional but the use of saline control solutions is mandatory. Using good equipment, down to 0.02 mg/1 phosphate can be determined by such procedures. For chloride contents above 18 000 mg/1, the chloride content of the wash should be within 5% of that in the sample. See also Sect. 3.6.1. 

At present, inductively coupled plasma mass spectrometry provides a unique, powerful alternative for the determination of rare earths in natural samples [638,639]. Nevertheless, its application to the determination of rare earths at ultratrace concentration level in seawater is limited, because highly saline samples can cause both spectral interferences and matrix effects [640]. Therefore, a separation of the matrix components and preconcentration of the analytes are prerequisites. To achieve this goal, many preconcentration techniques have been used, including coprecipitation with... 

Carr [562] has studied the effects of salinity on the determination of strontium in seawater by atomic absorption spectrometry using an air-acetylene flame. Using solutions containing 7.5 mg/1 strontium and between 5 and 14% sodium chloride, he demonstrated a decrease in absorption with increasing sodium chloride concentration. To overcome this effect a standard additions procedure is recommended. 

Figure 6.2. (a) The effects of salinity on the sensitivity of standard additions of ammonia in laboratory mixed waters ( ) and in waters from the Tamar estuary (A) expressed as percentage of response in river water. For comparison, the salt error curves reported by Loder and Gilbert [3] are also shown (... and —, respectively), (b) Contribution of reactive index and organic absorbance to the optical blacks in the Chemlab Colorimeter. = River water-seawater mixture, o = De-ionized water-seawater mixture. Source [2]... 

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. 

Sugatt, R.H. 1980a. Effects of sublethal sodium dichromate exposure in freshwater on the salinity tolerance and serum osmolality of juvenile coho salmon Oncorhynchus kisutch, in seawater. Arch. Environ. Contam. Toxicol. 9 41-52. 

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