S-3 

 SESTON 



All material, both organic and inorganic, 

 suspended in a waterway. Bioseston is the 

 living material; abioseston is the non-living 

 portion. 



SLUDGE DEPOSITS 



Accumulations of settled, usually rapidly 

 decomposing, organic material in the aquatic 

 system. A deposit of solids of wastewater 

 origin. 



SLIMES 



Substances of viscous organic nature, usually 

 formed from microbiological growth. 



SLUDGEWORMS 



Aquatic segmented worms (class - Oligochaeta) 

 that exhibit marked population increases in 

 waters polluted with decomposable organic 

 wastes. (See Bloodworms) 



SPAWN 



1. In aquatic animals, to produce or deposit 

 eggs or sperm. 



2. To produce eggs or young. 



3. Eggs of fishes and higher aquatic 

 invertebrates. 



SPECIES 

 (Both singular 

 and plural) 



An organism or organisms forming a natural 

 population, or groups of populations , that 

 transmit specific characteristics from 

 parent to offspring. Each species is 

 reproductively isolated from other populations 

 with which they might breed. Hybrids, the 

 results of interbreeding, usually exhibit a 

 loss of fertility. 



