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 are organisms that are actually very different biochemically and genetically from other bacteria. Hence, archaebacteria is an outdated term, and they are now classified in the Archaea domain. Classifications within this domain are unofficial due to debates over the descendancy of microbes.ydrothermal Vent Archaea. One example in the Archaea domain is Methanocaldococcus jannaschii, currently classified as Archaea: Euryarchaeota: Methanobacteria; Methanobacteriales: Methanobacteriaceae, Methanocaldococcus, and species jannaschii.