NPS The word “bacteria” is often associated with disease, but only a few kinds of bacteria cause problems for humans. The other thousands of bacteria, although all simple organisms, play a complex role in Earth’s ecosystems. In fact, cyanobacteria made our oxygenrich atmosphere possible. They were the first photosynthesizers, converting light energy into oxygen more than 3 billion years ago. Without bacteria, we would not be here. Most bacteria photosynthesize, providing oxygen which can then used by other thermophiles. Some use chemical sources of energy, like hydrogen or sulfur, to convert carbon dioxide into biomass other thermophiles can use (chemosynthesize). All of the cyanobacteria and green nonsulfur bacteria photosynthesize. Some fulfill both roles. For example, Thermus sp.—which are photosynthetic—also may be able to oxidize arsenic into a less toxic form. Individual bacteria may be rod or sphere shaped, but they often join end to end to form long strands called filaments. These strands help bind thermophilic mats, forming a vast community or miniecosystem. Other groups of bacteria form layered structures resembling tiny towers, which can trap sand and other organic materials.
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Last updated: August 29, 2019