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 --Prokaryotic, unicellular, nutrition by absorption (heterotrophic). This group of bacteria-like organisms live in harsh (high temperature, salinity, etc.) environments similar to that of ancient earth (hence the name). They cell wall structure is different than that of typical bacteria.