Oceans are ancient. And since they've been around for a good long time, some of the salts were added to the water at a time when gases and lava were spewing from an increase in volcanic activity. "The carbon dioxide dissolved in water from the atmosphere forms weak carbonic acid which dissolves minerals. Ions form when these minerals dissolve which makes the water salty. As water from the ocean evaporates, the salt gets left behind. Rivers draining into the ocean also bring additional ions from rock that was eroded by rainwater and streams. The saltiness or salinity of oceans remains pretty stable at 35 parts per thousand. "To give you a sense of how much salt that is, it is estimated that if you took all the salt out of the ocean and spread it over the land, the salt would form a layer more than 550 feet deep (166 meters)!" The reason, that oceans don't get increasingly saltier is that organisms that living there take in some of the salt. Another factor may be the formation of new minerals.
So, if you're like me, you might be asking, "If lakes get their water from rivers and streams and those are also in contact with the ground, then why aren't they salty, too?" Well, in fact, some are. Think of the Great Salt Lake and the Dead Sea. But the water in most lakes leaves to continue its journey to the sea. A drop of water and its associated ions will remain in one of the Great Lakes for around 200 years. But a drop of water and its salts may "hang out" in the ocean for as long as 100-200 million years, according to an article in Science Daily.
While most frogs prefer the water found in freshwater lakes, ponds, and swamps, there is at least one frog who enjoys living in salt water. But that's a blog for another day.
Tomorrow is Wednesday and that means a visit from my wise friend and mentor, The Dharma Frog. I hope you'll come back and join me for another of his inspiring and informative lessons. Until then,