the hard, variously colored, calcareous skeleton secreted by certain marine polyps. 2. such skeletons collectively, forming reefs, islands, etc. 3. the solitary or colonial polyp that secretes this calcareous skeleton.
Ancient methanogens are the source of natural gas. Halophiles are bacteria that thrive in high salt concentrations such as those found in salt lakes or pools of sea water. Thermophiles are the heat-loving bacteria found near hydrothermal vents and hot springs.
archaebacteria, archaebacterium, archaeobacteria, archeobacteria - considered ancient life forms that evolved separately from bacteria and blue-green algae. halobacter, halobacteria, halobacterium - halophiles in saline environments such as the Dead Sea or salt flats.