broken down into fertilizer. Aquariums In recent years, the word detritus has also come to be used in relation to aquariums (the word "aquarium" is a general term for any installation for keeping aquatic animals). When animals such as fish are kept in an aquarium, substances such as excreta, mucus and dead skin cast off during moulting are produced by the animals and, naturally, generate detritus, and are continually broken down by micro-organisms. Modern sealife aquariums often use the Berlin Method, which employs a piece of equipment called a protein skimmer, which produces air bubbles which the detritus adheres to, and forces it outside the tank before it decomposes, and also a highly porous type of natural rock called live rock where many bentos and bacteria live (hermatype which has been dead for some time is often used), which causes the detritus-feeding bentos and micro-organisms to undergo a detritus cycle. The Monaco system, where an anaerobic layer is created in the tank, to denitrify the organic compounds in the tank, and also the other nitrogen compounds, so that the decomposition process continues until the stage where water, carbon dioxide and nitrogen are produced, has also been implemented. Initially, the filtration systems in water tanks often worked as the name suggests, using a physical filter to remove foreign substances in the water. Following this, the standard method for maintaining the water quality was to convert ammonium or nitrates in excreta, which have a high degree of neurotoxicity, but the combination of detritus feeders, detritus and micro-organisms has now brought aquarium technology to a still higher level. See also Biofact (biology) Coarse woody debris Organic material Soil food web Citations Sources Bernard C. Patten (1975) Systems Analysis and Simulation in Ecology, Academic Press, 607 pages C. Michael Hogan (2008) "Western fence lizard (Sceloporus occidentalis)", Globaltwitcher, ed. Nicklas Stromberg David Author Grimaldi and Michael S. Author (2005) Engelevolution of the insects, Cambridge University Press Some of this article was translated from the equivalent article in the Japanese-language Wikipedia, as it was on September 1, 2006. Aquatic ecology Ecology terminology