Discuss the chemical composition of seawater - Book Report/Review Example

That is why salinity is often measured in terms of conductivity. The salinity of sea water that is usually found at 3.5 percent is important for survival of marine organism as water follows the principle of natural osmosis under which water flows toward higher concentration through cell walls. In cold seas salinity is found low when ice starts melting. In contrast, high salinity is found in ocean deserts where rainfalls are low and subjected to high evaporation. The Red Sea has high salinity due to its location in the desert region up to 4.0 percent. In contrast, the lowest salinity is found at 0.

5% in the Baltic Sea and the salinity of the Dead Sea is quite high up to 24 percent. It needs to be noted that proteins, carbohydrates, hormones are dissolve organics found in low concentrations in sea water but that are not a part of salinity. All dissolve elements of seawater can be further segregated as major elements, minor and trace elements, gases, nutrients, and organics. Content of Major Elements at Salinity of 35 Name of element Content, gms/kg Percentage of total Sodium 10.76 30.74 Chloride 19.353 55.29 Magnesium 1.292 3.69 Sulphate 2.712 7.75 Calcium 0.412 1.18 Potassium 0.399 1.14 Source:http://www.soest.hawaii.

edu/oceanography/courses/OCN623/Spring2012/Salinity2012web.pdf Major element in the sea water is sodium chloride that constitutes almost 85 percent of all the dissolved matter. When ca, mg, k and so4 are added to this than together they cover almost 99 percent of all the dissolved matter. During 1800s, it was discovered by the Challenger expedition that in most part of sea water, the relative proportion of constituents remains same. In simple terms, ratio of sodium and chloride by weight is found to be 0.

556 uniformly everywhere in the ocean. Regardless of salinity in sea water, this ratio does not change. Minor and trace elements are those which are found in quantity less than 1 ppm. Minor and trace elements are needed for the survival of species. It is pertinent to note that other 92 natural elements are traced in the ocean; however, they constitute a very small part of the total dissolve solids. Some of the elements such as cu, co, zn, Mn are so less in quantity that they are measured in parts per billion.

Nutrients in the ocean are silicon, phosphorus and nitrogen. Most marine plants in seawater use them in their dissolved forms instead of their elemental forms. For example nitrogen is consumed as ammonia, nitrate and nitrite; phosphorus in phosphates and silicon in sio2. These components vary in their concentrations across depth and length. Due to photosynthesis at the surface level they are found in very less concentration; however, they are found more at depth because creatures on their death release their bodily nutrients back in the water.

Biological activity is greatly associated with nutrient concentration. It is interesting to note that the concentration of prominent dissolved gases such as nitrogen, oxygen, carbon dioxide, argon in sea water differ from its concentration in atmosphere. Oxygen concentration in sea water goes down but at the same time nitrogen concentration increases. Similarly carbon dioxide concentration at the surface, due to photosynthesis goes down substantially. It is to be noted that nitrogen and argon do not support to life processes.

The chemical composition of sea water is also segregated in terms of