Ocean, salinity

Ocean surface layer salinity SMOS (planned for launch in the future), an ESA satellite to observe soil moisture and ocean salinity, equipped with microwave radiometer MIRAS. 

Changes in precipitation and evaporation over the oceans have led to water freshening in middle and high latitudes and to the growth in ocean salinity in low latitudes. 

Figure 4.7. The mean vertical distribution of (a) alkalinity and (b) total CO2 concentration normalized to the mean world ocean salinity value of 34.78. NA = North Atlantic, SA = South Atlantic, NP = North Pacific, SP = South Pacific, NI = North Indian, SI = South Indian, and A A = Antarctic region. (After Takahashi etal., 1980b.)...

Hay W. W., Wold C. N., Soding E., and Fliigel S. (2001) Evolution of sediment fluxes and ocean salinity. In Geologic Modelling and Simulations Sedimentary Systems (eds. D. F. Merriam and J. C. Davis). Kluwer Academic/ Plenum, Dordrecht, pp. 153-167. 

In hot climates, evaporation rates are high and ocean salinity ranges on the upper end of the scale. In the Red Sea and Persian Gulf, salinity may reach 42 percent. Salinity is also elevated in places where little or no new freshwater enters the system, or where water is trapped without a natural outlet. In the Dead Sea, water flows in from the Jordan River, but it has no path by which to leave the system. 

It should be noted that the lower artificial limit of the temperature range of the MCSST global data set is about —2°C (with regard to oceanic salinity). However, a processing of AVHRR-SST data for 2002-2004 made it possible to determine current freezing temperature Tfr as —7°C and estimate maximum seasonal range of SST for these years as 37°C for the open waters [25]. This value seems to be a world record for the World Ocean and inland seas. 

The scatter diagram of TS vs. TOC illustrates the S/C ratios of our samples (Fig. 7). Although the study area is a normal marine environment Le. clastic sediments overlain by oxic waters of typical oceanic salinity), most of the S/C ratios in the sediments are considerably lower than the average ratio of 1/2.8 obtained for reduced sulfur and organic carbon in sediments beneath oxygenated seawater (Berner, 1982). By contrast, the S/C ratios in our samples are mostly lower than 1/10, typically occurring in fresh water environments. Similarly, low S/C ratios have been observed in Amazon inner shelf muds (Alter et al, 1986 Alter and Blair, 1996). The authors attribute the low ratios to the oxidation power of iron oxides and reworking of sediments. Unlike the Amazon case, our samples are mostly from the slope and submarine canyons rather than the shelf and, therefore, deserve further discussion. 

Seawater is often referred to as saline water. The salinity of seawater is the mass in grams of dry salts present in 1 kg of seawater. In the world ocean, salinity averages about 35. To put it another way, seawater contains about 3.5% dissolved salts by mass. The list of elements present in seawater is very long. Most, however, are present only in very low concentrations. T TABLE 18.5 lists the 11 ionic species most abundant in seawater. 

An ocean is a major body of saline water, and a principal component of our planet s remarkable hydrosphere. Approximately 71% of the Earth s surface (an area of 361 million km (139 million mi ) is covered by ocean, a continuous body of seawater that is customarily divided into several principal named oceans and smaller named seas. More than half of this area is deeper than 3,000 m (9,842 ft). Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 31-38 ppt. Interestingly, the place furthest from the world-ocean—that is, the official pole of inaccessibility is in Asia (46° 17 N 86° 40 E), according to Garcia-Castellanos and Lombardo (2007). The volume of Earth s ocean is approximately 1.3 billion km (0.312 billion mi ), and its average depth is 3,790 m (12,434 ft). The vast volume of the deep ocean (anything below 200 m, 656 ft) covers about 66% of our Earth s surface. 

Earth s oceans Salinity is a measure of the mass of salts dissolved in seawater, usually measured in grams of salt per kilogram of seawater. Most salt in the ocean is dissociated into ions. 

---