Salinity stratification

Water. Many factors must be considered to obtain representative samples of water. The most important are the pollutant and the point at which it entered the aquatic environment. Pollutants can be contributed by agricultural, industrial, municipal, or other sources, such as spills from wrecks or train derailments. The prevailing wind direction and speed, the velocity of stream or river flow, temperature, thermal and salinity stratification, and sediment content are other important factors. 

Keywords Large Aral Sea, Salinization, Stratification, Thermohaline regime. Internal waves... 

Specific Adaptation to Depth and Salinity Stratification Across the Basins and in the Channel... 

Figure 7. Proposed model of the Phosphoria sea showing the interplay of continental wind currents, upwelling ocean currents, algal blooms, and salinity stratification (modified from Stephens and Carroll 1999).

Slansky M (1986) Geology of Sedimentaiy Phosphates. North Oxford Academic, London Smith JP, Lehr JR (1966) An X-ray investigations of carbonate apatite. J Agric Food Chem 14 342-349 Stephens NP, Carroll AR (1999) Salinity stratification in the Permian Phosphoria sea a proposed paleoceanographic model. Geology 27 899-902... 

ITl The lower atmospheric boundary layer with diel characteristics (thermal density stratification) 1T2 The stratified aquatic system (thermal and salinity stratification)... 

Bottom water currents in sluggish streams (i.e., bayous), lakes, estuaries, and other near-shore marine waters are moved by the wind at the surface. Both thermal and salinity stratification in these waters is a factor influencing the magnitudes of the bottom-water transport coefficients. Although this subject of MTCs has received limited study, some estimation methods are proposed. For unstratified water bodies. Equation 12.10 is useful wind speed is a key independent variable. For stratified lakes surface winds cause seiches that generate bottom water currents. Equations 12.11 through 12.13 can be used with seiche water displacement heights. To estimate bottom currents, these values are converted to bottom friction velocities with Equation 12.8, Equation 12.1 is then used for the MTC estimate. Bed characteristics can be used as proxies for bottom currents see Table 12.5. 

Land (1987) has reviewed and discussed theories for the formation of saline brines in sedimentary basins. We will summarize his major relevant conclusions here. He points out that theories for deriving most brines from connate seawater, by processes such as shale membrane filtration, or connate evaporitic brines are usually inadequate to explain their composition, volume and distribution, and that most brines must be related, at least in part, to the interaction of subsurface waters with evaporite beds (primarily halite). The commonly observed increase in dissolved solids with depth is probably largely the result of simple "thermo-haline" circulation and density stratification. Also many basins have basal sequences of evaporites in them. Cation concentrations are largely controlled by mineral solubilities, with carbonate and feldspar minerals dominating so that Ca2+ must exceed Mg2+, and Na+ must exceed K+ (Figures 8.8 and 8.9). Land (1987) hypothesizes that in deep basins devolatilization reactions associated with basement metamorphism may also provide an important source of dissolved components. 

Figure 3.7 The general categories of estuarine circulation identified as Type A, well-mixed estuaries, where there is minimal vertical stratification in salinity Type B, partially mixed estuaries, where the vertical mixing is inhibited to some degree Type C, highly stratified with lower freshwater discharge than the salt wedge system and Type D, salt wedge estuary and many fjords. (Modified from Bowden, 1980.)...

Hansen and Rattray (1966) first introduced the idea of using stratification-circulation diagrams to describe a spectrum of circulation and geomorphometric types of estuaries that can be defined by stratification (figure 3.9). The basic classification parameters are as follows the stratification is defined by SS/Sq where <5,8 is the difference in the salinity... 

Figure 3.9 Stratification-circulation diagrams used to describe a spectrum of circulation and geomorphometric types of estuaries that can be defined by stratification. Estuarine types are as follows Type 1 estuaries are those without upstream flow requiring tidal transport for salt balance Type 2 estuaries are partially mixed (e.g., Marrows of the Mersey (NM) (UK), James River (J) (USA), Columbia River estuary (C) (USA) Type 3 estuaries are representative of fjords [e.g., Siver Bay (S), Strait of Juan de Fuca (JF) (USA)] and Type 4 estuaries indicative of salt wedge estuaries [e.g., Mississippi River (M) (USA)]. The basic classification parameters are as follows the stratification is defined by SS/Sq where SS is the difference in the salinity between surface and bottom water and So is the mean-depth salinity, both averaged over a tidal cycle and Us/Uf, where U is the surface velocity (averaged over a tidal cycle) and Uf is the vertically averaged net outflow. The subdivisions a and b represent values where SS/Sq <0.1 and SS/Sq >0.1, respectively subscripts h and 1 refer to high and low river flow. The curved line at the top represents the limit of surface freshwater outflow. (From Hansen and Rattray, 1966, as modified by Jay et al., 2000, with permission.)...

Well-mixed estuaries minimal vertical stratification in salinity. 

Increase in the input of the organic matter and nutrients into the Black Sea causes increase of total phytoplankton biomass. In summer due to formation of the temperature, salinity and density stratification and algal blooms, decay of dead phytoplankton leads, in turn, to the oxygen lack and near-bottom hypoxia [9]. These processes have to consider as the consequence of anthropogenic eutrophication of the sea [9]. 

The evolution of the Black Sea anoxic zone is closely connected with the evolution of its stratification pattern, presently characterized by the existence of a strong pycnocline separating the upper freshwater-influenced surface layer, with a salinity of 17.5-18.5%o, and the deep water mass below ca. 150-200 m, with a salinity of 22.3%o at the bottom. Models for evolving Black Sea salinity after the opening of Bosporus agree that salinity in bottom waters reached 90% of present-day values about 3000 years after the Bosporus opening [14-17]. 

In their hypothesis of a glacial decrease in Southern Ocean CO2 leak, early workers considered two causes (i) an increase in biological export production and (ii) a decrease in the exposure rate of deep waters at the polar surface (Figure 7). One can imagine processes that would have reduced the evasion of CO2 from the Southern Ocean by either of the two mechanisms mentioned above. For instance, an increase in the input of dust and its associated trace metals to the Southern Ocean might have driven an increase in the rate of nutrient and carbon uptake by phytoplankton (Martin, 1990). Alternatively, an increase in the salinity-driven stratification of the Antarctic and/or a decrease in wind-driven upwelling could have lowered the rate of nutrient and carbon dioxide supply to the surface... 

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