Denitrifying bacteriaDenitrifying bacteria are a diverse group of bacteria that encompass many different phyla. This group of bacteria, together with denitrifying fungi and archaea, is capable of performing denitrification as part of the nitrogen cycle. Denitrification is performed by a variety of denitrifying bacteria that are widely distributed in soils and sediments and that use oxidized nitrogen compounds in absence of oxygen as a terminal electron acceptor. They metabolise nitrogenous compounds using various enzymes, turning nitrogen oxides back to nitrogen gas (N2) or nitrous oxide (N2O).
CalcareousCalcareous (kælˈkɛəriəs) is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. Calcareous is used as an adjectival term applied to anatomical structures which are made primarily of calcium carbonate, in animals such as gastropods, i.e., snails, specifically in relation to such structures as the operculum, the clausilium, and the love dart.
FaunaFauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding term for plants is flora, and for fungi, it is funga. Flora, fauna, funga and other forms of life are collectively referred to as biota. Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils.