Closed ecological systems (CES) are ecosystems that do not rely on matter exchange with any part outside the system.
Although the
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
itself fits this definition, the term is most often used to describe much smaller manmade ecosystems. Such systems are scientifically interesting and can potentially serve as a
life support systemIn human spaceflight, the life support system is a group of devices that allow a human being to survive in outer space. NASA often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for its human spaceflight missions. The life support...
during space flights, in space stations or
space habitatA space habitat is a space station intended as a permanent settlement rather than as a simple waystation or other specialized facility...
s.
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
mouseA mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. The American white-footed mouse and the deer mouse also sometimes live in houses. In some places, certain kinds of field mice are also common...
or a
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
, waste products such as
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
, faeces and
urineUrine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...
must eventually be converted into
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
,
foodFood is any substance, usually composed of carbohydrates, fats, proteins and water, that can be eaten or drunk by an animal, including humans, for nutrition or pleasure. Items considered food may be sourced from plants, animals or other categories such as fungus or fermented products like alcohol...
, and
waterWater is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71%...
.
A closed ecological system must contain at least one
autotrophAn autotroph is an organism that produces complex organic compounds from simple inorganic molecules using energy from light or inorganic chemical reactions....
ic organism. While both
chemotrophChemotrophs are organisms that obtain energy by the oxidation of electron donating molecules in their environments. These molecules can be organic or inorganic . The chemotroph designation is in contrast to phototrophs which utilize solar energy...
ic and
phototrophPhotoautotrophs or Phototroph are organisms that carry out photosynthesis to acquire energy. Energy from sunlight, carbon dioxide and water are converted into organic materials to be used in cellular functions such as biosynthesis and respiration...
ic organisms are plausible, almost all closed ecological systems to date are based on a phototroph such as green
algaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in...
.
Examples
Major (large-scale) closed ecological systems include
Biosphere 2Biosphere 2 is a structure originally built to be a man-made, materially-closed ecological system in Oracle, Arizona by Space Biosphere Ventures, a joint venture whose principal officers were John P. Allen, inventor and Executive Director, and Margret Augustine, CEO...
,
MELiSSAThe acronym MELiSSA means 'Micro-Ecological Life Support Alternative' and is a development program of a microbiological and horticultural plant based ecosystem...
, and the BIOS-1, BIOS-2, and
BIOS-3BIOS-3 was a closed ecosystem at the Institute of Biophysics in Krasnoyarsk, Siberia, in what was then the Soviet Union.Construction began in 1965, and was completed in 1972. BIOS-3 consisted of a 315-cubic-metre habitat suitable for up to three persons. It is divided into 4 compartments —...
projects.
An
ecosphereThe EcoSphere and "Original Ecosphere" are trademark names for sealed blown-glass miniature aquaria produced by Ecosphere Associates, Inc., of Tucson, Arizona, United States. Spherical or ovoid, the aquaria range from roughly baseball-size to soccer-ball-size...
is a glass enclosed, self-contained and self-sustaining closed ecosystem sold primarily as a gift or experiment. It can include tiny
shrimpShrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
,
algaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in...
,
gravelGravel is rock that is of a specific particle size range. Specifically, it is any loose rock that is larger than two millimeters in its smallest dimension and no more than . The next smaller size class in geology is sand, which is > in size. The next larger size is cobble, which is >. Gravel can...
, decorative shells, and gorgonia.
Also
bottle gardenA bottle garden is a container similar to a terrarium in which plants are grown. They usually consist of a plastic or glass bottle with a narrow neck and a small opening...
s can act as a closed ecological system.
See also
- Biosphere 2
Biosphere 2 is a structure originally built to be a man-made, materially-closed ecological system in Oracle, Arizona by Space Biosphere Ventures, a joint venture whose principal officers were John P. Allen, inventor and Executive Director, and Margret Augustine, CEO...
- Controlled Ecological Life Support System
Controlled Ecological Life Support Systems are a type of scientific endeavor to create a self-supporting life support system for space stations and colonies typically through controlled closed ecological systems, such as the BioHome, BIOS-3 and Biosphere 2.-Original concept:CELSS was first...
- Ecospace
- Eden Project
The Eden Project is a visitor attraction in the United Kingdom, including the world's largest greenhouse. Inside the artificial biomes are plants that are collected from all around the world....
- Space colonization
Space colonization is the concept of autonomous human habitation of locations outside Earth....
- Terraforming
Terraforming of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to those of Earth to make it habitable by terran organisms.The term is sometimes erroneously used more generally as a synonym...
Sources
- "Manmade Closed Ecological Systems." I. I. Gitelson, G. M. Lisovsky and R. D. MacElroy. Taylor & Francis (2003) ISBN 0-415-29998-5.