Q&A: Why is the ocean salty? The rivers aren’t & they feed into the ocean. The rain isn’t & it falls on the ocean. So why is the sea salty?

When our patron asked, we not only gave him books about the ocean & the water cycles, but we also went to ask.com to see what we could find from government sources and/or educational institutions such as universities. These are the best places to find solid information about reference questions.

The first, thorough (very long) answer is by Herbert Swenson:

“This information is from a general interest publication ("Why is the Ocean Salty?" By Herbert Swenson) prepared by the U.S. Geological Survey to provide information about the earth sciences, natural resources, and the environment.”

For a much shorter version of, “Why is the Ocean Salty?” go to the U.S. Geological Survey website which starts out:

“If you get into folk stories and mythology you will see that almost every culture has a story explaining how the oceans became salty. The answer is really very simple. Salt in the ocean comes from rocks on land. Here's how it works…”

“…By some estimates, if the salt in the ocean could be removed and spread evenly over the Earth’s land surface it would form a layer more than 500 feet (166 m) thick, about the height of a 40-story office building.”

Information courtesy of the Argonne National Laboratory. [Read the whole article]

More information, suggested by the USGS on why the ocean is salty: "…Why are some of Earth’s waters salty and others not? There are two clues that give us the answer. First, 'fresh' water is not entirely free of dissolved salt. Even rainwater has traces of substances dissolved in it that were picked up during passage through the atmosphere. Much of this material that 'washes out' of the atmosphere today is pollution, but there are also natural substances present…

"…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…" [Read the whole article]

But here’s the part I REALLY enjoyed from the USGS website’s answer, “…By the way, the concentration of salt in seawater (salinity) is about 35 parts per thousand. In other words, about 35 of 1,000 (3.5%) of the weight of seawater comes from the dissolved salts; in a cubic mile of seawater the weight of the salt, as sodium chloride, would be about 120 million tons. And, just so you don't think seawater is worthless, a cubic mile of it also can contain up to 25 tons of gold and up to 45 tons of silver! Before you go out and try alchemy on seawater, though, just think about how big a cubic mile is….”

My question is:

How long do you think it will be before someone comes up with an extremely efficient way to extract the gold & silver from the ocean?

Let’s see: 25 tons of gold times 2000 pounds/ton equals 50,000 pounds of gold times 16 ounces/pound equals 800,000 ounces times $300.00/ounce equals $240,000,000.00. Wow!

And, before you get all excited about the 16 ounces/pound…I know that there are only 12 TROY ounces in a TROY pound which is what they use to weigh precious metals. But if you look at this chart:

“480 grains = 1 troy ounce
5760 grains = 1 troy pound
437.5 grains = 1 ounce avoirdupois
7000 grains = 1 pound avoirdupois”

You’ll realize that even though a troy ounce weighs less than a regular ounce, a regular pound weighs more than a troy pound. So, I’m actually erring on the conservative side. But what’s a few ounces one way or the other when you’re talking about 240 million dollars?! ENJOY!!