Why Sea Water is Salty
The “salt” in sea water, and some lakes that have no water outlet such as the Great Salt Lake and the Dead Sea, comes from ions of dissolved minerals, mainly chloride and sodium which make up about 90% of salt ions in sea water. There are three main ways that dissolved minerals enter the ocean: The water cycle, underwater geysers know as Hydrothermal Vents, and underwater volcanos.
During the water cycle, water is evaporated from bodies of water by the heat of the sun. The evaporated water rises through the atmosphere as a gas, or vapor. As the vapors rise they cool and turn back into tiny droplets of water which attach to each other forming clouds by the process of condensation. During precipitation, the water falls back to the earth in the form of rain, snow or sleet. Some of the water seeps into the earth to underground reservoirs, or aquifers (UOD, 2004). The rest of the water is runoff, and it flows back to the rivers, lakes, and oceans where it began. Along the way this water picks up minerals from rock and soil and deposits them in these bodies of water. The constant movement of rivers and lakes prevents the buildup of “salt”, but in oceans and other bodies of water without an outlet, the minerals remain in the water because they do not evaporate.
In 1977, scientists discovered geysers, or hydrothermal vents on the seafloor in the Pacific Ocean. These vents form along the Mid-Ocean Ridge when the huge plates that make up the Earth’s crust move apart causing deep cracks in the floor of the ocean. Seawater seeps into these cracks and is heated by the molten rock below the Earth’s crust. As the water heats, chemical reaction begin to occur, and oxygen and minerals are removed from the water. As it goes deeper and gets hotter, certain metals and sulfur dissolve into it, and then the fluid begins to rise. It gushes back to the ocean floor, meeting with the near-freezing, oxygen-rick seawater, causing more...
Please join StudyMode to read the full document