There is abundant aquatic life in the oceans. From the microscopic planktons to huge whales, different types of living things are found in the oceans. Once they die, their remains accumulate in oceans.
All rivers flowing from mountains or hilly areas finally meet the ocean. Sediments from eroded lands, trees and bushes flowing with the water, dead remains, etc. enter the ocean with this river water.
In both the above processes, the dead remains decompose, releasing various minerals and salts in the ocean water.
Volcanic eruptions occur on land. Similar volcanic eruptions take place in the ocean as well. During volcanic eruptions different minerals, ashes, salts and gases are added to the water. Tis increase the level of salts and minerals in ocean water.
Due to the continuous evaporation of oceanic waters, the proportion of salts increases. All these things make the ocean water salty.
The salinity of ocean water is different at different place. The average salinity of oceanic water is 35%. The Dead Sea is known to have the maximum salinity. It salinity higher.
We obtain salt from the salty waters. Salts as a substance is obtained by constructing salt pans in the coastal areas.
Many minerals like phosphate, sulfates, iodine, etc. are also obtained from the sea.
We depend on the oceans to some extent for minerals.
Ocean play important role in humankind. Natural resources are obtaining form ocean depth. Today Scientist has found many medicinal plants to treat dangerous disease form the ocean.