This brings up another thing I wonder about---
Is it possible the sky is blue because of the waters?
It's possible, or also frozen oxygen is blue (there's some speculation that the firmament is made of solid/frozen oxygen). There are also the noble gases in the upper reaches of the atmosphere. I saw one intriguing video from a Flat Earther (though this isn't strictly related to Flat Earth), where he argues that during daylight, it's some of these noble gases that light up as the sun has an electric charge (rather than simply projecting light across the sky). He showed a lot of phenomena that seeemd to back up this theory, and he demonstrated how various noble gases turn that color of blue when subjected to electric charges, and it also explained a lot of the other colors you'll see during sunrise and sunset. There's a lot more about create that we don't understand than what we do.
This is frozen/solid oxygen --

There was one guy who CLAIMED to be a whistleblower who said that he worked in Antarctica, and that they would go to the edges and get samples of "sky ice" that they determined was made of frozen oxygen.