A line in Action Comics #244 from 1958 about there being 84 pounds of pure gold in every cubic mile of water got me thinking and with a quick back of an envelope calculation I worked out there had to be at least 100 Trillion US dollars worth of gold in the Earth’s oceans.
The volume of water in the Earth’s oceans according to Wikipedia is 310 million cu mi
The current price of gold is 943 US dollars troy ounce
There are 14.58 troy ounces in a pound.
161 962 513 200 000 dollars