How to grow food without light? This is what I call "thinking outside the box"!

http://www.geocities.com/womplex_oo1/StarshipGenerations.html

He's right about one thing, it could be dangerous! The starship generations text mentions that the bacteria living around hrdrothermal vents feeds on hydrogen sulfide. Hydrogen sulfide, H2S, is deadly in any serious amount of PPM's (parts per million). Further it is heavier than air, meaning that it will collect in low places. It smells of rotten eggs and has the ability to deaden the olfactory nerves. This means that you get 1 whiff after that no warning. If that's not enough, it will make metal brittle over time and weaken the structure of the metal so that it will not stand up to any sharp blow, pressure, expansion or contraction, or vibration. Not what I'd want on a starship.

Hydrothermal Chemosynthesis is just one type. There are other types of chemosynthesis that may be useful for growing food, and some may occur in much more benign environments. However the "deep sea vents" example does emphasize that life can thrive in the total absence of sunlight, the same scenario expected for space missions beyond Mars.