Why do we study the HYDROSPHERE?
About two-thirds of the world's population lives within 500 km of a coastline. Therefore, the natural variations in the oceans have an impact on many people. In addition, oceans, seas, lakes, ponds, rivers and streams that make up the hydrosphere contribute many things to society:
1. Nourishment Many early people used the water in cooking, cleaning, and other aspects of living to help sustain their people. They also used the fish and seafood from the nearby bodies of water to feed themselves. This is also true today of people who live near large bodies of water. Today many people dedicate their lives to harvesting the fish and seafood from the hydrosphere. Fishing vessels, sometimes traveling very far from home, gather fish and seafood to feed the world. Drinking water is critical to life - without fresh water, humans can live only a few days.
In Peru, the anchovy fishermen depend on the harvest of anchovies to provide for their families; however, the occurrence of El Niño, a large warming of the waters in the tropical Pacific, has a large impact on the anchovy harvest. The normally cold waters in the eastern tropical Pacific Ocean contain many nutrients that feed the anchovies. When the warm waters from the western tropical Pacific Ocean move to the east, these nutrients remain at deep levels in the ocean and are unavailable for the anchovies. As a result, the anchovies die or move elsewhere, destroying the annual harvest for the Peruvian fishermen. Thus, the Peruvian fishermen would benefit greatly if the phenomenon of El Nino could be predicted, so that they can be better prepared to deal with the impact on their lives.
2. Transportation Rivers and ocean currents were the original highways of mankind. Rivers permitted people to travel relatively quickly from one region to another and to move large quantities of goods from where they were obtained or made to the marketplace.
Once mankind could reliably sail across the Atlantic Ocean, the ocean currents provided a means by which trade could occur between continents. Today these trade routes across the ocean are still being used.
3. Power Moving water can also be used for power. In historical times, water wheels on small rivers and streams provided the power needed to grind wheat and corn into meal for use in making food. Today large dams are built on rivers, and the release of the water produces large quantities of hydroelectric power used by many cities. In addition, the large lakes that form upstream of the dam provide large recreational areas.
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