

Ask HN: Resources in one cubic mile of sea water - digamber_kamat

One cubic mile of sea water contains — besides the 130 million tons of salt — 6 million tonnes of magnesium, 25 tons of gold, 135 tons of silver, etc.<p>Can some one point out to me a source which will validate 
(or invalidate) above statement?
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lifeisstillgood
Gold measured in Seawater in 1990 - "just 1 gram of gold for every 100 million
tonnes of sea water (Earth and Planetary Science Letters, vol 98, p 208)."
[http://www.newscientist.com/article/mg12717242.800-science-g...](http://www.newscientist.com/article/mg12717242.800-science-
gold-in-sea-water--not-enough-to-get-rich-.html)

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cperciva
To save everyone else the trouble of translating units: 1 gram per 100 million
tons is approximately 47 grams per cubic mile.

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digamber_kamat
how did u convert this ?

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lifeisstillgood
(I did a similar calc and from memory it was)

1mile ~ 1.6km 1cubic mile = 1600 * 1600 * 1600 m3 ~ 4.1 bn m3 1m3 = 1000 ltrs
& 1 ltr (pure water) = 1kg so 1m3 ~ 1 ton 1cubic mile ~ 4.1 bn tons so 1g /
100m tons ~ 41 grams per cubic mile

The 41/47 is probably a better weight for seawater than my 1kg/ltr.

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lifeisstillgood
cperciva, thank you for clarifying what I should have put in there in the
first place.

Anyway, this seems a good overview and is not wildly out with the other
literature afaik.

[http://books.google.co.uk/books?id=LbTDLa_2opsC&pg=PA26&...](http://books.google.co.uk/books?id=LbTDLa_2opsC&pg=PA26&source=gbs_selected_pages&cad=3#v=onepage&q=&f=false)

so, 130m tons of salt is supported, 6m tons of magnesium, but 1 ton of silver
and 0.02 tons of gold, and commercial extraction seems limited to salt
(obviously) magnesium and bromine. I suspect someone quoted the "boring"
elements accurately and then upvoted the "fun" elements for you.

