IS WATER THE SAME IN OCEANS, RIVERS, AND LAKES? - CULTURE VOCABULARY - 2025

The water in oceans, rivers and lakes is not the same. Although they apparently have a similar appearance, their chemical composition is different, which gives them well-differentiated characteristics.

The water of the seas and oceans is a solution composed of water and salts, in an estimated proportion of 65 by 35%.

In contrast, other bodies of water such as rivers and lakes have a minimal composition of dissolved salts. Because of this antagonism, river and lake water is commonly referred to as fresh water.

The vast majority of the water present on the planet corresponds to ocean waters and seas. The remnant is the water contained in lakes, rivers, waterfalls, streams, glaciers, swamps, groundwater, lagoons, and springs.

The salt and fresh water bodies have multiple differences, depending on the analysis of each physico-chemical property.

The 4 main differences between fresh water and salt water

1- Salinity

The water in the oceans and seas has a salinity of 3.5%. This salinity, in order of importance, is distributed between sodium chloride (common salt), magnesium chloride, magnesium sulfate, and calcium sulfate.

That is, for every liter of sea or ocean water, there are 35 grams of salts to its credit.

In contrast, the salinity of rivers is quite low. If the concentration of salts is higher than 0.5%, it may be due to the geology of the land, weather conditions or water pollution.

For its part, the salinity of the lakes is usually very variable. Generally the concentration of salts in the water will depend on the opening of the lakes towards the sea:

- If the lake is closed (that is, if it does not have an outlet to the sea) the salinity can be quite high due to the concentration of saline compounds.

- If the lake is open, it will have an abundant and constant flow of water, and the salinity is usually much lower due to the circulation of the body of water.

2- Color

Sea or ocean water normally has a bluish color whose hue tends to become more intense depending on the depth of the water.

Unlike rivers and lakes, the coloration of its waters comes as a consequence of the elements that are present in the ecosystem, as a product of the decomposition of plants and organic materials.

The color of the water is also related to the pH of this element: the water becomes darker as the pH increases.

3- Density

Salt water is much denser than fresh water, due to the high concentration of sodium chloride found in seas and oceans.

That is why it is always easier to float in salt water, because the density of sea water is 3% higher than the density of water in rivers and lakes.

4- Temperature

The temperature of seas and oceans varies depending on the altitude. The oceans are generally colder, given the depth of their waters.

In the case of lakes and rivers, the temperature depends on the distribution and flow of the sun's rays throughout the body of water.

References

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