I'm not 100% sure because the colony mechanics are a little opaque but I don't think you directly supply the colony, meaning they do not suck resources out of your pockets throughout the game. So, you can't cut them off directly.
However, as pbhead mentions, the size of the colony is heavily effected by the prices of commodities (particularly life support - Water, Food, Oxygen, Power(?)). There is/was also a "jobs" element to it but it is unclear what drives the quantity of jobs.
It's difficult to tell currently how a big colony vs. a small colony effects the prices in the game. For example,does a large colony drive up the price of Electronics?