Oceans have kept a pretty steady balance of salt over time. One litre of sea water contains about 35 grams (3500 milligrams) of salt. That's about six teaspoons.
Oceans regularly receive small amounts of new salt from river water that flows into them, and from molten rock exposed by cracks in the ocean floor.
At the same time, oceans lose salt to the formation of new rocks.
Deep under the ocean, there are cracks in the ocean floor. The cracks are called deep-sea vents. The cracks are the path for the mechanism that helps maintain the ocean' salt level.
The deep-sea vents allow superheated water to escape from inside the Earth. This superheated water has minerals and salt dissolved in it. Thus, the salt and minerals are brought into the ocean.
Once they reach the ocean, the salt and minerals cool, solidify and fall to the sea floor. There, they pile up around the opening of the vent and form chimneys that are tens of metres tall. The vents are called hydrothermal vents or black smokers.
Black smokers are home to unusual creatures that are adapted to this environment. They include bacteria and giant tubeworms.
Video (51 sec.)
Neptune and VENUS in the Ocean
If the undersea world interests you, then take advantage of the observations made in projects by Neptune Canada and VENUS. They offer images and information about the bottom of the ocean.
The projects are located in the Pacific Ocean near Vancouver Island, British Columbia. Through their observatories, scientists study the chemistry, physics, geology and biology of the sea floor.
Watch videos from this project on the Canadian Museum of Nature's YouTube channel:
Visit their web site: