There’s about fifty pounds of gold in every cubic mile of sea water....
Do you have a source for this illogical comment?
Gold is heavy, it would sink to the bottom making it very easy to scoop up. There may be parts of the ocean with high concentraions on the bottom but to extrapolate that to every cubic mile is jsut illogical.
NOAA
Is there gold in the ocean?
Ocean waters do hold gold – nearly 20 million tons of it. However, if you were hoping make your fortune mining the sea, consider this: Gold in the ocean is so dilute that its concentration is on the order of parts per trillion. Each liter of seawater contains, on average, about 13 billionths of a gram of gold.
There is also (undissolved) gold in/on the seafloor. The ocean, however, is deep, meaning that gold deposits are a mile or two under water. And once you reach the ocean floor, you’ll find that gold deposits are also encased in rock that must be mined through. Not easy.
Currently, there really isn’t a cost-effective way to mine or extract gold from the ocean to make a profit. But, if we could extract all of that gold, there’s enough of it that each person on Earth could have nine pounds of the precious metal. Eureka!
http://oceanservice.noaa.gov/facts/gold.html