'Closed ecological systems' (CES) are
ecosystems that do not rely on matter exchange with any part outside the system.
Although the
Earth itself fits this definition, the term is most often used to describe much smaller ecosystems. Such systems are scientifically interesting and can potentially serve as a
life support system during
space flights, in
space stations or
space habitats, or in
submarines.
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 higher life form, such as a
mouse or a
human, waste products such as
carbon dioxide,
faeces and
urine must eventually be converted into
oxygen,
food, and
water.
A closed ecological system must contain at least one
autotrophic organism. While both
chemotrophic and
phototrophic organisms are plausible, almost all closed ecological systems to date are based on a phototroph such as green
algae.
Major (large-scale) closed ecological systems include
Biosphere 2,
MELISSA, and the
BIOS-1,
BIOS-2, and
BIOS-3 projects.
An
ecosphere is a glass enclosed, self-contained and self-sustaining closed ecosystem sold primarily as a gift or experiment. It can include tiny
shrimp,
algae,
gravel, decorative
shells, and
gorgonia.
See also
★
Ecospace
★
Space colonization
★
Terraforming
★
Controlled Ecological Life Support System
Sources
★ "Manmade Closed Ecological Systems." I. I. Gitelson, G. M. Lisovsky and R. D. MacElroy. Taylor & Francis (2003) ISBN 0-415-29998-5.