Dark Sector

The Dark Sector is dedicated to the ecosystem that thrives at ocean depths farther than the light of the sun can penetrate. Most of the life in the dark center is congregated on the ocean floor. This region is rich with scavengers, deep sea fish, and other organisms that consume the waste and carcasses of other animals that sink from the light zone of the ocean.

The ocean floor is home to many unique communities of plants and animals. Most of these marine ecosystems are near the water surface, such as the Great Barrier Reef, a 2,000-km-long coral formation off the northeastern coast of Australia. Coral reefs, like nearly all complex living communities, depend on solar energy for growth (photosynthesis). The sun's energy, however, penetrates at most only about 300 m below the surface of the water. The relatively shallow penetration of solar energy and the sinking of cold, subpolar water combine to make most of the deep ocean floor a frigid environment with few life forms.

The story about the source of life-sustaining energy in the deep sea is still unfolding. In the late 1980s, scientists documented the existence of a dim glow at some of the hot geothermal vents, which are the targets of current intensive research. The occurrence of "natural" light on the dark seafloor has great significance, because it implies that photosynthesis may be possible at deep-sea geothermal vents. Thus, the base of the deep-sea ecosystem's food chain may comprise both chemosynthetic and, probably in small proportion, photosynthetic bacteria.