Sea Salinity?

Question

Why is the sea salty?
is it getting any saltier?
If it is getting more or less salty, will this kill the turtles etc...

Answer 1

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. The dissolved salts carried by all the world’s rivers would equal the salt in the ocean in about 200 to 300 million years.

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. Why are these lakes salty while most of the world’s lakes are not? Lakes are temporary storage areas for water. Rivers and streams bring water to the lakes, and other rivers carry water out of lakes. Thus, lakes are really only wide depressions in a river channel that have filled with water. Water flows in one end and out the other.

The Great Salt Lake, Dead Sea, and other salt lakes have no outlets. All the water that flows into these lakes escapes only by evaporation. When water evaporates, the dissolved salts are left behind. So a few lakes are salty because rivers carried salts to the lakes, the water in the lakes evaporated and the salts were left behind. After years and years of river inflow and evaporation, the salt content of the lake water built up to the present levels. The same process made the seas salty. Rivers carry dissolved salts to the ocean. Water evaporates from the oceans to fall again as rain and to feed the rivers, but the salts remain in the ocean. Because of the huge volume of the oceans, hundreds of millions of years of river input were required for the salt content to build to its present level.

Rivers are not the only source of dissolved salts. About twenty years ago, features on the crest of oceanic ridges were discovered that modified our view on how the sea became salty. These features, known as hydrothermal vents, represent places on the ocean floor where sea water that has seeped into the rocks of the oceanic crust, has become hotter, and has dissolved some of the minerals from the crust, now flows back into the ocean. With the hot water comes a large complement of dissolved minerals. Estimates of the amount of hydrothermal fluids now flowing from these vents indicate that the entire volume of the oceans could seep through the oceanic crust in about 10 million years. Thus, this process has a very important effect on salinity. 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 the water.

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.

Will the oceans continue to become saltier? Not likely. In fact the sea has had about the same salt content for many hundred of millions if not billions of years. The salt content has reached a steady state. Dissolved salts are being removed from seawater to form new minerals at the bottom of the ocean as fast as rivers and hydrothermal processes are providing new salts.

We can summarize this discussion. Wherever water comes into contact with the rocks of Earth’s crust, either on land or in the ocean or within the oceanic crust, some of the minerals in the rock dissolve and are carried by the water to the ocean. The salt content of seawater does not change because new minerals are forming on the sea floor at the same rate as salt is added. Thus, the salt content of the sea is at steady state.

Answer 2

What sea are you asking about? Perhaps you mean the oceans? Some SEAS - like the Dead Sea are getting saltier. Some polar seas are getting less saline because of ice melt associated with global warming. The oceans remain fairly constant in their salinity over the years . Some variation occurs during glacial ages and interglacial ages.
Many can tell you how the oceans get their salt influx, but if the salinity remains pretty constant, how do they lose the salts? When waves break or white caps are blown, the sea spray sends tiny drops of saline water into the air where they evaporate. This leaves a tiny salt crystal to float in the air. These act as hygroscopic nuclei which are essential in the formation of raindrops. The rain falls back to Earth where the salt water can return to the seas/oceans.

Any global changes in the average salinity of the oceans will take place over many years. Surely most marine life will adapt to the changing environs as they have for many times in the past.

Answer 3

The sea is salty because of erosion of minerals that blah, blah, blah. So most people say, but they are wrong. The thing that really controls Oceanic salinity are minerals released from black and white smokers, and from mid-ocean ridges. Sure, continental sources have some input into ocean salinity, but not the major input. I have not heard of any studies to determine changes in salinity, nor if those changes have a drastic effect on sea life.

Answer 4

The sea is salty because it receives the mineral salts from all the watersheds in the world with a few notable exceptions. Also the sun evaporates the water leaving the salts behind.

It is getting less salty

turtles can probably adapt.

Answer 5

hole? in ozone would decree,salt water is getting purer.