[bruce511]

>> Who made any claims of self-sustaining?

No one in the article. But it has come up in the comments of previous articles (and I see in this thread as well.)

Life on land is self sustaining. Not in the "we don't need oceans" sense, but in the "we don't need people living in the oceans" sense. Conversely to live in the ocean we (currently) must have people living on land.

[fragmede]

land is a pretty broad stroke though, and there are obviously specific areas of land that aren't self-sustaining, so it depends on how you want to slice it. So if these end up being only slightly more self-sustaining as, say McMurdo base in Antarctica, it doesn't seem like a showstopper for habitation.

[marssaxman]

Las Vegas, for that matter, cannot possibly exist in the environment where it was built without constant support from habitable places.