Editing Closed ecological system (section)

{{short description|Ecosystem that does not exchange matter with the exterior}}
[[Image:biosphere2 1.jpg|thumb|right|300px|[[Biosphere 2]]]]

'''Closed ecological systems''' or '''contained ecological systems''' ('''CES''') are [[ecosystems]] that do not rely on matter exchange with any part outside the system.

The term is most often used to describe small, man-made ecosystems. Such systems can potentially serve as a [[life support system|life-support system]] or [[space habitat]]s.<ref>{{cite book | title=Manmade Closed Ecological Systems | author= [[Josef Gitelson|I. I. Gitelson]] | author2= G. M. Lisovsky | author3= R. D. MacElroy | name-list-style= amp | publisher= [[Taylor & Francis]] |date=2003 | isbn = 0-415-29998-5}}</ref>

In a closed ecological system, any waste products produced by one species must be used by at least one other species. If the purpose is to maintain a life form, such as a [[mouse]] or a [[human]], waste products such as [[carbon dioxide]], [[feces]], and [[urine]] must eventually be converted into [[oxygen]], [[food]], and [[water]].

A closed ecological system must contain at least one [[autotroph]]ic organism. While both [[chemotroph]]ic and [[phototroph]]ic organisms are plausible, almost all closed ecological systems to date are based on an autotroph such as green [[algae]].