Seawater volume

In particular for the chemical concentrations in Table 20.4, units referring to a solute volume mean the gas volume under normal conditions (0°C, 101 325 Pa). Units relative to solvent volumes refer to seawater volumes at 20°C, 101 325 Pa with unspecified salinity rather than to in situ conditions (IOC, 1987). Because of the small haline contraction... 

The following sequence of steps is repeated during sample analysis first, the peristaltic pump is switched on, and the sample loop is flushed with filtered seawater from the selected intake, while the cryogenic unit is operated to cool the column. Then, the 6-port valve is actuated into the sample injection position and the trapped seawater volume is forced into the purge vessel by the carrier gas stream. The sample is degassed, and volatiles are cryocon-... 

The seawater volume flow rate through the duct is 2sw- The duct includes some pumps (main parameters consumed pumping power Pp). The necessary power is provided by PV cells (collection area Apy, produced electrical power pv)- The speed Wsw of seawater in the duct of diameter >duct is given by ... 

The fluxes in hoUow-fiber membranes used in seawater desalination are 20—30-fold smaller, but the overall RO system size does not increase because the hoUow-fiber membranes have a much larger surface area per module unit volume. In use with seawater, their RR is about 12—17.5% and the salt rejection ratio is up to 99.5%. 

Traditional Processes. The two primary stripping vapors are steam and air. Steam is used when the concentration of bromine in brine is greater than 1000 ppm. The advantage is that bromine can be condensed direcdy from the steam. Air is used when seawater is the source of bromine because very large volumes of stripping gas are needed and steam would be too expensive. When air is used the bromine needs to be trapped in an alkaline or reducing solution to concentrate it. 

The procedure for phase separation follows the schematic in Figure 4-115 [32A]. To prepare the three test phases, a 1 9 ratio by volume of mud to seawater is mixed for 30 min. The pH is adjusted to that near seawater (pH = 7.8-9.0) by the addition of acetic acid. The slurry is allowed to settle for one hour. A portion of the supernatant is filtered through a 0.45- im filter. The filtrate is designated as the liquid phase. The remaining unfiltered supernatant of the slurry is the suspended particulate phase, while the solid phase is the settled solid material at the bottom of the mixing vessel. 

The density of seawater is controlled by its salt content or salinity and its temperature. Salinity is historically defined as the total salt content of seawater and the units were given as grams of salt per kilogram of seawater or parts per thousand (%o). Salinity was expressed on a mass of seawater basis because mass, rather than volume, is conserved as temperature and... 

There is some debate about what controls the magnesium concentration in seawater. The main input is rivers. The main removal is by hydrothermal processes (the concentration of Mg in hot vent solutions is essentially zero). First, calculate the residence time of water in the ocean due to (1) river input and (2) hydro-thermal circulation. Second, calculate the residence time of magnesium in seawater with respect to these two processes. Third, draw a sketch to show this box model calculation schematically. You can assume that uncertainties in river input and hydrothermal circulation are 5% and 10%, respectively. What does this tell you about controls on the magnesium concentration Do these calculations support the input/removal balance proposed above Do any questions come to mind Volume of ocean = 1.4 x 10 L River input = 3.2 x lO L/yr Hydrothermal circulation = 1.0 x 10 L/yr Mg concentration in river water = 1.7 X 10 M Mg concentration in seawater = 0.053 M. 

It is experimentally difficult to obtain numerical estimates of the total number of bacteria present in seawater, and the contribution of ultramicroorganisms that have a small cell volume and low concentrations of DNA may be seriously underestimated. Although it is possible to evaluate their contribution to the uptake and mineralization of readily degraded compounds such as amino acids and carbohydrates, it is more difficult to estimate then-potential for degrading xenobiotics at realistic concentrations. 

Fig. 4.3. (A) Composite multispecies benthic foraminiferal Mg/Ca records from three deep-sea sites DSDP Site 573, ODP Site 926, and ODP Site 689. (B) Species-adjusted Mg/Ca data. Error bars represent standard deviations of the means where more than one species was present in a sample. The smoothed curve through the data represents a 15% weighted average. (C) Mg temperature record obtained by applying a Mg calibration to the record in (B). Broken line indicates temperatures calculated from the record assuming an ice-free world. Blue areas indicate periods of substantial ice-sheet growth determined from the S 0 record in conjunction with the Mg temperature. (D) Cenozoic composite benthic foraminiferal S 0 record based on Atlantic cores and normalized to Cibicidoides spp. Vertical dashed line indicates probable existence of ice sheets as estimated by (2). 3w, seawater S 0. (E) Estimated variation in 8 0 composition of seawater, a measure of global ice volume, calculated by substituting Mg temperatures and benthic 8 0 data into the 8 0 paleotemperature equation (Lear et al., 2000).

N. J. E. Dowling, J. Guezennec, and D. C. White. Facilitation of corrosion of stainless steel exposed to aerobic seawater by microbial biofilms containing both facultative and absolute anaerobes. In Proceedings Volume. Inst Petrol Microbiol Comm Microbial Problems in the Offshore Oil Ind Int Conf (Aberdeen, Scotland, 4/15-4/17), 1986. 

J. P. Salanitro, M. P. Williams, and G. C. Langston. Growth and control of sulfidogenic bacteria in a laboratory model seawater flood thermal gradient. In Proceedings Volume, pages 457-467. SPE Oilfield Chem Int Symp (New Orleans, LA, 3/2-3/5), 1993. 

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