A— Continued 



aquaculture— The farming of fish, shellfish, 

 algae and other aquatic organisms and 

 the development of methods of rearing 

 aquatic organisms. See also algaculture 

 and mariculture. 



aquatic— Growing or living in, or frequent- 

 ing, water— as opposed to terrestrial. 



assimilation— The uptake of food material 

 for production of new biomass. 



association— In an ecological sense, a 

 subunit of community organization 

 identified by its major organisms. 



aufwuchs— See periphyton. 



autecology— The study of the individual 

 organism or species rather than the 

 community. Life history and behavior, 

 rather than adaptation to environment, 

 are usually emphasized. 



autogenic succession — Succession induced 

 by biotic processes acting from within 

 the system. 



autolysis— Self-breakdown of a cell. This is 

 one pathway in detrital recycling of 

 nutrients. 



autotomy— The process of self -amputation 

 of extremities or organs by reflex action. 

 Regeneration usually follows. 



autotroph— A self -nourishing organism that 

 makes its own food from inorganic 

 components. 



autotrophic— (1) The process by which an 

 organism manufactures its own food 

 from inorganic compounds. (2) The 

 ability to use simple inorganic substances 

 and an energy source for synthesis of 

 more complex compounds (e.g., green 

 plants). Compare with hetrotrophic. 



autotrophic succession — A type of com- 

 munity succession in which productivity 

 exceeds respiration in early successional 

 stages, but the two tend to equilibrate in 

 more mature stages. Compare with 

 heterotrophic succession. 



B-- 



balanus zone — The area where balanoid 

 (stalkless, sessile) barnacles inhabit the 

 shore, generally restricted to part of 

 certain intertidal and splash zones. 



barriers — In an ecological sense, those 

 physical, chemical, climatic or biologic 

 factors which are foreign to an orga- 

 nism's native habitat and exceed the 

 tolerance of that organism. These factors 

 may offer enough resistance to stop the 

 dispersal or force the retreat of that 

 organism. 



benthic — Pertaining to the subaquatic 

 bottom. 



benthos— A collective term describing: (1) 

 Bottom organisms attached or resting on 

 or in the bottom sediments. (2) Com- 

 munity of animals living in or on the 

 bottom. 



bioassey— The use of living organisms as an 

 index to determine environmental con- 

 ditions. 



Biochemical Oxygen Demand (BOD)— The 



amount of oxygen required by the 

 biological population of a water sample 

 to oxidize the organic matter in that 

 water. It is usually determined over a 

 5-day period under standardized labora- 

 tory conditions and hence may not 

 represent actual field conditions. 



