Thanks... I understand all that, though not on the level you posted.
My question was sort of tongue-in-cheek, referring to the lack of large bodies of salt water in space...
Sorry I though people were serious that space would be a dark and energy less place. You are right about the salt water thing only a few other bodies in the solar system have salt water that we are reasonably sure is liquid all be it at depth; Europa, Ganymede and Castieo however none of them have liquid water at the surface. Jupiter cooks them with lethal levels of radiation not a place for humans to make a landing. The idea of floating bags in the ocean to make fuel is kinda silly given that we have gigatons of fossil carbon under our land and ocean floor just waiting for us to dig it up the green fallacy is just that a logical fallacy. What does make sence is using algae for waste water clean up on a regional scale and for the production of sugars to feed animals with, some algae are also 60% protein by dry wgt too growing livestock food in brackish waste water in the desert would be a good idea but the corn lobby has such power to keep a strangle hold on the North American food chain we as in most Americans are by atomic isotope analytics 80% carbon from corn it is in almost every ingredient of our food chain.