Aerobic - (of an organism or tissue) requiring the presence of air or free oxygen for life.

1. a colorless, pungent, suffocating, highly water-soluble, gaseous compound, NH3, usually produced by the direct combination of nitrogen and hydrogen gases: used chiefly for refrigeration and in the manufacture of commercial chemicals and laboratory reagents.

2. Also called ammonia solution, ammonia water, aqua ammoniae, aqua ammonia, aqueous ammonia. this gas dissolved in water; ammonium hydroxide.

Anaerobic - (of an organism or tissue) living in the absence of air or free oxygen.

Anoxia (Anoxic, adj.) - Absence of oxygen.

Autotroph (Autotrophic, adj.) - Any organism capable of self-nourishment by using inorganic materials as a source of nutrients and using photosynthesis or chemosynthesis as a source of energy, as most plants and certain bacteria and protists.

Aquaculture - The cultivation of aquatic animals and plants, esp. fish, shellfish, and seaweed, in natural or controlled marine or freshwater environments; underwater agriculture.

Bacteria - Ubiquitous one-celled organisms, spherical, spiral, or rod-shaped and appearing singly or in chains, comprising the Schizomycota, a phylum of the kingdom Monera (in some classification systems the plant class Schizomycetes), various species of which are involved in fermentation, putrefaction, infectious diseases, or nitrogen fixation.

Dentrification

1. to remove nitrogen or nitrogen compounds from.
2. to reduce (nitrates) to nitrites, ammonia, and free nitrogen, as in soil by microorganisms.

Faculative - Having the capacity to live under more than one specific set of environmental conditions, as a plant that can lead either a parasitic or a nonparasitic life or a bacterium that can live with or without air (opposed to OBLIGATE).

Heterotroph - An organism that cannot synthesize its own food and is dependent on complex organic substances for nutrition.

Mineralization - To convert to a mineral substance.

Nitrate - The univalent radical NO3 or a compound containing it, as a salt or an ester of nitric acid.

Nitrite - A salt or ester of nitrous acid.

Nitrification (the act of nitrifying)

1. To oxidize (an ammonia compound) into nitric acid, nitrous acid, or any nitrate or nitrite, especially by the action of nitrobacteria.
2. To treat or combine with nitrogen or compounds containing nitrogen.

Nitrobacter - A salt or ester of nitrous acid.

Nitrogen - A colorless, odorless, gaseous element that constitutes about four-fifths of the volume of the atmosphere and is present in combined form in animal and vegetable tissues, esp. in proteins: used chiefly in the manufacture of ammonia, nitric acid, cyanide, explosives, fertilizer, dyes, as a cooling agent.

Nitrogen Cycle - The continuous sequence of events by which atmospheric nitrogen and nitrogenous compounds in the soil are converted, as by nitrification and nitrogen fixation, into substances that can be utilized by green plants, the substances returning to the air and soil as a result of the decay of the plants and denitrification.

Nitrosomonas - Ellipsoidal Soil Bacteria.