Ecosphere (aquarium)
Ecosphere is the brand name for a special aquarium , the inhabitants of which, enclosed in a glass ball, can survive for several years without external intervention. This represents a simplified, artificial " ecosystem ". Ecosphere is the English word for ecosphere .
content
Inside the transparent, spherical container there is air , salt water , green algae and shrimp , which feed on the green algae, as well as bacteria , which are destructive and convert the shrimp's excretions back into nutrient salts that can be used by the algae . In addition, there is a coral , stones and snail shells in the glass to provide a base for the algae. Natural light or artificial light is energy supplied. It is enough to keep the shrimp in these ecosystems alive for an average of 2 to 3 years.
However, there are also isolated cases in which the ecospheres have been alive for over 10 years. This is not much, as the shrimp have a natural life expectancy of over 10 years and the animals are said to have already reproduced in the spheres in individual cases.
The shrimp are the species Halocaridina rubra , which can get by with little food for a very long time and then lives on their body substance. This is an evolutionary adaptation to the natural habitat of this species, which also includes subsurface water that is poor in food and oxygen. The species is very peaceful. Compared to the simple algae and bacteria, these shrimp represent the most demanding species of the simple ecosystem. Specially developed ecospheres without shrimp (only contain algae and bacteria) have remained alive for over 18 years.
functionality
The functionality or the basic principle behind the Ecosphere is relatively simple and thus mimics natural ecosystems. It is based on a self-contained cycle of materials , in which, however, energy is constantly "consumed". The inhabitants of the Ecosphere can be divided into three areas:
- The algae take up nutrient salts from the water and convert them into organic material when light falls through the energy made usable by photosynthesis , whereby they grow and release oxygen into the water as a waste product of photosynthesis ( producers ).
- The shrimp, in turn, breathe in the oxygen released by the algae and breathe out the carbon dioxide that the algae need for photosynthesis and feed on them ( consumers ).
- The bacteria finally also need the oxygen from the algae and convert the excretions of the shrimp and other dead material back into nutrient salts, which in turn can be used by the algae, releasing carbon dioxide into the water ( destructors ).
Thus, all the important components of an ecosystem are present, which means that the whole system is completely self-sufficient , apart from the necessary energy supply in the form of light and heat from the environment . With regard to the consideration of the light requirement, the choice of the installation site is of decisive importance; the sphere must not receive too much or too little light. Six to twelve hours of light a day are recommended, which means both artificial light and daylight. Underexposure the algae cannot develop properly, while overexposure can lead to algal blooms , which is also bad for the balance in the Ecosphere.
The ecospheres are also quite sensitive to the temperatures , especially because of the shrimp. In order to keep the miniature ecosystem stable in the long term, the temperatures should be permanently between 15 ° C and 30 ° C and ideally not fall below or exceed these extreme values.
Development history
In 1849 Robert Warington , the founder of the "Chemical Society" in London, developed the "Plant and Fish Pond", an ecological balance system for the maintenance-free keeping of two goldfish . Aquatic plants of the genus Vallisneria produced oxygen and food. Mud snails , whose young were also eaten by the fish, served as waste disposers . It is very likely that many types of bacteria and algae were also involved in this experiment. The biological equilibrium was maintained for years in daylight.
A replica of this system in the form of a water-filled glass ball about one meter in size is in the Natural History Museum in Vienna . In 1852 Justus von Liebig was inspired by the "Plant and Fish Pond" in Munich to create his "Liebig world in a glass", which was also a sealed aquarium.
The development of the Ecosphere as a result of a technology transfer from NASA is presented on the provider's website . As a result, the product is also advertised with the NASA logo.
costs
The prices range from around € 100 for a ball with a diameter of approx. 10 cm to € 1500 for a ball diameter of about 40 cm, with the balls differing not only in size but also in the number of shrimp. In addition, there is usually a stand in the range of 10 € to 20 €.
criticism
In general, keeping animals in closed aquariums is not considered optimal in the aquarium hobby. The shrimp usually die in the spheres well before they reach their normal life expectancy. It is therefore obvious that the shrimp suffocate in the spheres or starve to death within 1 to 3 years. Other shrimp species that are not adapted to life in extremely nutrient-poor and oxygen-poor environments would likely die even faster. It is also not a species-appropriate keeping, because the animals have very few hiding places and little space available.
Proponents of the Ecosphere counter the criticism with the argument that a dead shrimp is eaten by the remaining shrimp and that the destructors (bacteria and microorganisms) decompose the remains within a few days. Because all the factors necessary for an ecosystem are present in the Ecosphere, nitrite poisoning can not occur, and the food for the shrimp is also sufficient because of the regrowth of the algae. From an ecological point of view, however, it is clear that the prerequisite for this is that the Ecosphere receives sufficient light without the temperature in the water fluctuating too much. In contrast to larger ecosystems (desert, lake, seashore, stream), the Ecosphere does not offer the possibility of rebalancing the living conditions after a disturbance through migration or immigration of species or through exchange of the atmosphere with neighboring areas.
See also
Web links
- Information and instructions ( English )
- Information and instructions ( German )