T-4 

 TOXICITY 



Quality, state or degree of the harmful effect 

 resulting from alteration of an environmental 

 factor. 



TRIPTON 



The dead suspended particulate matter in 

 aquatic habitats; the nonliving portion of 

 the Seston. 



TROPHIC LEVEL 



One of the parts in a nutritive series in an 

 ecosystem in which a group of organisms in a 

 certain stage in the food chain secures food 

 in the same general manner. The first or 

 lowest trophic level consists of producers 

 (green plants) ; the second level of herbivores ; 

 the third level of secondary carnivores . 

 Most bacteria and fungi are organisms in the 

 reducer (decomposer) trophic level. 



TROPHOGENIC 

 REGION 



The area of a body of water where organic 

 production from mineral substances takes 

 place on the basis of light energy and 

 photosynthetic activity. 



TROPHOLYTIC 

 REGION 



The deep area of a body of water where organic 

 breakdown predominates because of light 

 deficiency. 



TURNOVER 



( Overturn) 



