is an organism that relies on an energy-producing metabolism or metabolisms that do not utilize oxygen (O2

are microbes that often resemble bacteria in size and shape but contain genes and metabolic pathways that are more similar to those of eukaryotes. They are, however, genetically distinct from both Bacteria and Eukarya, the other two domains of life on Earth. Archaea are found in a broad range of habitats, some very extreme, and are numerous in the [..]

, also known as self-feeders or primary producers, are organisms that produce complex organic compounds, such as carbohydrates, fats, and proteins, from carbon dioxide using light energy (photosynthesis) or inorganic chemical energy (chemosynthesis).

are a large domain of microbes that are present in most habitats on Earth, including the ocean and crust, and encompass a tremendous diversity of metabolisms. Bacteria are genetically distinct from Archaea and Eukarya, the other two domains of life on Earth. N.B. “bacteria” is the plural form of “bacterium.”

are a large domain of microbes that are present in most habitats on Earth, including the ocean and crust, and encompass a tremendous diversity of metabolisms. Bacteria are genetically distinct from Archaea and Eukarya, the other two domains of life on Earth. N.B. “bacteria” is the plural form of “bacterium.”

is all of the physical material, alive and dead, of biological origin for a designated sample or system. Biomass can be calculated as wet (including water mass) or dry (without). It is sometimes calculated on a carbon-specific basis, that is, the mass of all of the carbon excluding hydrogen, oxygen, nitrogen or another element. For example, a 150-l [..]

refers to all the life present in a given system, integrating all the communities there, and generally separated from other environments. Often used to refer to Earth’s life in its entirety, the term can also apply to any closed, self-regulating system, such as an ecosystem. The deep biosphere constitutes all the life found starting several feet be [..]

is the biological conversion of nutrients and simple carbon compounds, usually carbon dioxide or methane, into organic matter using chemical energy. This is exemplified by the microbes that live off of sulfur and / or metals brought up from below the surface, whether by nature (e.g. hot springs) or humans (e.g. mine tailings). Chemosynthesis is dis [..]

crust

refers to the habitat at the bottom of oceans or lakes, on top of the sea floor or lake bed. Familiar demersal fish include flounder, halibut, and cod, among many others.