In a new survey of the sub-seafloor off the U.S. Northeast coast, scientists have found a gigantic aquifer of relatively fresh water that would be roughly 15,000 square mi if on Earth's surface. It is in sediment below the ocean floor. This suggests that aquifers may lie off many coasts worldwide.

Admitting that they are comparing extraction processes for two completely separate fluids with completely different rheologies (as well as them being classified as ionically separate substances, one being polar, and the other being nonpolar) to analyze costs is a very poor way to demonstrate expertise in the field of oceanography. The fact that the substance needing to be extracted carries similar density to the substance it is submerged in, without the same risks of contaminating the environment simplifies the process. Desalination is usually discouraged because of the amount of waste it produces that have short term effects on the environment. We have yet to discover if there would be long term effects of displacing the underground aquifers with seawater, but this is now getting beyond the point.

The principle of charity says that perhaps, oceanography has nothing to do with estimating engineering costs, which is why the author used poor analogies. Their appeal to authority added nothing at all to their answer.

/r/science Thread Parent Link - nature.com