Atlantic Ocean, salinity, temperature

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... 

Fig. 21.4 Vertical sections showing distribution of temperature, salinity, and oxygen in the Western Atlantic Ocean (After Wiist). (After Sverdrup, H. U., Oceanography for Meteorologists,...

Longitudinal profiles in the Atlantic Ocean at about 25°W. (a) Potential temperature (°C), (b) salinity, (o) potential density (0 dbar), (d) potential density (4000 dbar), and (e) dissolved oxygen ( j,mol/kg). Source-. After Talley, L. (1996). Atlantic Ocean Vertical Sections and datasets for selected lines. http /sam.ucsd.edu/vertical.sections/Atlantic.html. Scripps Institute of Oceanography, University of California - San Diego. Data are from WOCE hydrographic program. (See companion website for color version.)... 

Fig. 4. Schematic representation of surface currents in the north Atlantic Ocean and stations where surface waters were collected. Areas I to V indicate regions with common temperature, salinity and nutrient characteristics.

North Atlantic Ocean. Surface samples in north Atlantic waters were collected at 20 stations in Tuly-August 1983. The area is influenced mainly by the Gulfstream, the North Atlantic Drift and the much colder East Greenland Current. The surface samples can be grouped into fives areas with common characteristics of temperature, salinity, phosphate and silicate concentrations, Fig. 4 (Kramer, 1986). 

Ocean, which is slightly higher than that of the Atlantic Ocean. The third driving force is the difference between the salinity and the temperature of the waters near the equator and near Greenland in the north. 

Figure 2.6 Air-sea flux densities of N2 (bold lines) calculated as F = (0.39ujq ) (SRCair-Cair) (Scn2/660) (Wanninkhof, 1992). SR stands for the N2 saturation ratio and Um stands for the wind speed in a height of 10m. Water temperature and salinity were set to 25° C and 35, respectively. C ir is the equilibrium concentration of atmospheric N2 and was calculated with the equation given by Hamme and Emerson (2004). The dashed lines represent maximum (3110 pmol N m day ) and minimum (161 pmol N m day ) mean N2 fixation rates for the North Atlantic Ocean (Capone et a/., 2005).

Superimposed on the general depth-dependent decrease of carbonate accumulation observed everywhere in the deep sea are preservation patterns that differ between the major ocean basins. Today, carbonate-rich sediments tend to accumulate in the Atlantic Ocean, while more carbonate-poor sediments are generally found at comparable water depths in the Indian and Pacific Oceans. This modern pattern is largely the product of the ocean s thermohaline circulation and has been termed basin-to-basin fractionation . In the Atlantic, deep and bottom waters tend to be produced at high latitudes because cold temperatures and high sea surface salinities lead to the formation of dense water... 

Fig. 21.4 Distribution of temperature, salinity and oxygen in the western Atlantic Ocean...

Deep Ocean— The deep ocean environment is very different from the ocean at the surface. At sites in the North Atlantic and North Pacific Oceans, oxygen, temperature, and salinity vary with depth. At the ocean surface, the oxygen concentration in the North Pacific is 1.4 times the oxygen content in the North Atlantic. In addition, both the surface temperature and surface salinity are lower in the North Pacific than in the North Atlantic. Below about 1500 m, however, temperature and salinity levels are approximately the same at these two ocean sites [1,6. ... 

The dynamics of fecal coliforms in coastal waters depends in part on bacterial loading from streams and rivers, mass transport, and bacterial losses due to death and sedimentation. The rates at which they disappear from surface waters depend on many factors such as availability of nutrients, temperature, salinity, turbidity, degree of water mixing, solar radiation, predation, and competition [3,41,47,64,92,97,143]. However, temperature and solar radiation are considered the most important abiotic factors [39,153]. For example, Xu et al. [153] found that temperature, solar radiation, and temperature and insolation combined, explained 31%, 78%, and 87%, respectively, of coliform bacteria dieoff coefficients in a lagoon on a French Island (Noirmountier), in the Atlantic Ocean. Predation by protozoans is a major biotic factor influencing fecal coliform death rates it accounted for 47%-99% of the mortality in the Seine River, France [54,98]. 

Because temperature (T) and salinity (S) are the main factors controlling density, oceanographers use T-S diagrams to describe the features of the different water masses. The average temperature and salinity of the world ocean and various parts of the ocean are given in Fig. 10-3 and Table 10-3. The North Atlantic contains the warmest and saltiest water of the major oceans. The Southern Ocean (the region around Antarctica) is the coldest and the North Pacific has the lowest average salinity. 

The density of the water controls the deepwater circulation. If the density of a water body increases, it has a tendency to sink. Subsequently, it will spread out over a horizon of uniform circulatory system is also known as thermohaline circulation. As shown in Figure 5 of the ocean conveyor belt, the densest oceanic waters are formed in Polar Regions due to the relatively low temperatures and the salinity increase that results from ice formation. Antarctic Bottom Water (ABW) is generated in the Weddell Sea and flows northward into the South Atlantic. North Atlantic Deep Water (NADW)... 

Latitudinal cross section of the potential temperature and salinity of the Atlantic (A) and Pacific (B) oceans. Different water masses are definable by their characteristic temperature and salinity (Table 1.3). (Plotted by using Ocean Data View and WOCE hydrographic data (Schlitzer, 2001).)... 

A useful apphcation of preformed nutrient concentrations is that they are intrinsic to different water masses and sometimes can be used as conservative tracers. For example, the main sources of deep water in the Pacific Ocean are North Atlantic Deep Water (NADW), Antarctic Intermediate Water (AAIW) and Antarctic Bottom Water (AABW), all of which are at least partly homogenized in the Antarctic Circumpolar Water (AACW). It is not possible to determine how much of each of these sources contributes to Pacific deep water by using end member mixing of the conservative properties temperature and salinity because salinities of the end members are not sufficiently different. Since concentrations of DIP are well above detection limits in... 

Fig. 9-5 Average temperature/salinity diagrams for the main water masses of the Atlantic, Indian, and Pacific Oceans. Reproduced from Pickard and Emery (1982) with the permission of Pergamon Press.

---