Bacteria have found a way to live in almost every environment on our planet. They live in near-boiling hot mud pools at Yellowstone Park; they eat crude oil; they even, says this article: Iron Will to Live for Antarctic Microbes, live under Antarctic glaciers, in environments with almost no oxygen and no carbon.

Most organisms on our planet use respiration to provide energy for their internal functioning. In respiration, oxygen is used to burn carbon compounds (like sugars) to provide energy. Not these bacteria, which use sulfur-based compounds called sulfates.

If you look at the periodic table, you will see that sulfur falls just below oxygen, in the same column. Like carbon, it readily forms complex compounds that store energy. The Antarctic bacteria use iron found in the local rock to react with the sulfur compounds (called sulfates) and obtain energy through a different biochemical method.