The reactions between seawater and oceanic basalt, the rock of ocean crust, are not one-way, however; some of the dissolved salts react with the rock and are removed from seawater. A final process that provides salts to the oceans is submarine volcanism, the eruption of volcanoes under water.
This is similar to the previous process in that seawater is reacting with hot rock and dissolving some of the mineral constituents. Humans cannot drink saline water, but, saline water can be made into freshwater, for which there are many uses. The process is called "desalination", and it is being used more and more around the world to provide people with needed freshwater. In your everyday life you are not involved much with saline water.
You are concerned with freshwater to serve your life's every need. But, most of Earth's water, and almost all of the water that people can access, is saline, or salty water. Do you wear contact lenses? If so, you most likely use a saline water solution to clean them. But what else do we use saline water for and do we really use that much? Read on to learn all about the use of saline water. Skip to main content. Search Search. Water Science School. Why is the Ocean Salty?
Water Basics Information by Topic Topics. Science Center Objects Overview Related Science Multimedia FAQ The oceans cover about 70 percent of the Earth's surface, and that about 97 percent of all water on and in the Earth is saline—there's a lot of salty water on our planet.
So, the answer to why rivers and lakes are not as salty as the oceans is that salts and minerals that enter have an avenue for escape, which is a path to the oceans. The primary way that water leaves the oceans is through evaporation, and that process leaves salts and minerals behind. No outlet means a buildup of those things, and a salty ocean.
Science Review As an avid fisherman, this article was very interesting to me. See More As an avid fisherman, this article was very interesting to me. Guissella Madrid, 0. Great read! See More Reviews. Too Much Salt? See More This quick to read article gives a very concise explanation of why oceans are salty and lakes and rivers do not appear to be but actually have salt in them.
Sandra Gady Renton, WA. Salt and water Robertson provides a wonderful explanation that salt exists in all water and why it is more evident in some places than others. See More Robertson provides a wonderful explanation that salt exists in all water and why it is more evident in some places than others. Everyone also knows that fresh water in rain, rivers, and even ice is not salty.
There are two clues that give us the answer. Even rainwater has traces of substances dissolved in it that were picked up during passage through the atmosphere. As rainwater passes through soil and percolates through rocks, it dissolves some of the minerals, a process called weathering.
This is the water we drink, and of course, we cannot taste the salt because its concentration is too low. Eventually, this water with its small load of dissolved minerals or salts reaches a stream and flows into lakes and the ocean. The annual addition of dissolved salts by rivers is only a tiny fraction of the total salt in the ocean. A second clue to how the sea became salty is the presence of salt lakes such as the Great Salt Lake and the Dead Sea.
Both are about 10 times saltier than seawater. That depends on location and season. For comparison, open ocean waters average a 3. In her story on the colorful salt lakes Down Under, my colleague Kathryn Hansen describes how they formed:. Millions of years ago, declines in rainfall caused river flows to ebb and river valleys to fill in with sediment. Wind then sculpted the loose sediment to form the lake basins that remain today.
The wind also sculpted some of the lighter sediments into parallel dunes that fringe each lake downwind to the east-southeast. Some of the lakes now fill with runoff directly from the Stirling Range; others are controlled primarily by groundwater. The lakes below in Western Australia range from pea soup-brown to pinkish in hue. Their color changes based on sediments, aquatic and terrestrial plant growth, water chemistry, algae, and hydrology. At Urmia , the rise and fall of lake also has an effect on water color:.
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