From Scientific American:
In the textbook description of photosynthesis, sunlight fuels the production of sugars that are in turn converted into fuel for the photosynthetic organism. But a recent discovery from the deep blue sea may force a revision of that account. Scientists have found a photosynthetic bacterium that doesn’t live off the light of the sun. Instead, it uses the dim light given off by hydrothermal vents some 2,400 meters below the ocean’s surface.
More here.