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Q79- Though local salinity patterns are largely determined by rainfall and evaporation, the salinity of the oceans is determined globally by a number of factors. Evaluate. (250 words)
- Paper & Topic: GS I à Geography
- The entire content of dissolved salts in sea water is referred to as salinity.
- The amount of salt (in gm) dissolved in 1,000 gm (1 kg) of saltwater is used to calculate it.
- At 0 degrees Celsius, the salinity of ocean water is normally around 35 parts per thousand.
- This means that dissolved salts account for 3.5 percent of the total weight of ocean water.
- The most prevalent dissolved salt in the sea is sodium chloride, sometimes known as common salt.
- Salinity is influenced by a number of factors, including:
- Controlling variables of oceanic salinity are elements that influence the quantity of salt in different oceans and seas.
- Evaporation: Evaporation determines the salinity of water in the ocean's surface layer. Salinity is higher where evaporation is greater, as as in the Mediterranean Sea.
- Inflow of freshwater: Freshwater flow from rivers has a big impact on surface salinity in coastal areas, while ice freezing and thawing has a big impact in polar regions.
- Where there is a higher flow of freshwater into the oceans, the salinity is lower.
- The ocean surface salinity in the mouths of rivers like the Amazon, Congo, and Ganga, for example, is found to be lower than the average surface salinity.
- Temperature and density: Water's salinity, temperature, and density are all linked. As a result, any change in temperature or density has an impact on an area's salinity.
- In general, places with high temperatures also have high saline levels.
- Ocean currents: They influence the spatial distribution of dissolved salts in ocean waters.
- Warm currents near the equator push salts away from the ocean's eastern boundaries, where they collect near the western margins.
- In temperate locations, ocean currents enhance the salinity of ocean waters near the eastern edges. For example, the Gulf Stream in the North Atlantic Ocean raises the salinity of ocean waters around the Atlantic Ocean's western edges.
- Precipitation: There is an inverse link between precipitation and salinity.
- In general, regions with higher precipitation levels have lower salinity levels.
- This is why, although being as hot as the subtropics, the equatorial region has lower salinity than the subtropics because the former receives more precipitation each day.
- Wind direction and atmospheric pressure: anti-cyclonic circumstances with steady air and high temperatures increase the salinity of ocean surface water.
- Winds aid in salinity redistribution by driving saline waters away from more saline locations, resulting in a decrease in salinity in the former and an increase in the latter.
- The density of saltwater, as well as its vertical flow patterns in thermohaline circulation, is determined by salinity and temperature.
- Around 3 billion tonnes of salt are introduced to the oceans each year from the land.
- Humans remove only a small portion of this salt for everyday ingestion.