What Kinds Of Energy Support Life?
All organisms require energy to fuel their life processes of growth, maintenance and reproduction. The known forms of life use two forms of energy – light and chemical. Plants, algae and some bacteria photosynthesize and therefore fall into the first category. Animals, fungi and non-photosynthesizing bacteria fall into the second. Most chemical eaters ultimately depend on photosynthesis to obtain their organic matter and oxygen. Until recently, we thought that all life cycles were directly dependent on light for their energy. Then in 1977, we discovered deep sea ecosystems that are sustained almost entirely by chemical energy, such as those that flourish around the black smokers in the picture above. Black smokers dump large amounts of hydrogen sulfide into the surrounding water, which sulfur eating bacteria metabolize. These bacteria form symbiotic relationships with other life forms, such as tubeworms, allowing them to survive where other life forms cannot. Black smokers dump large a
