E-3 

 ESTUARY 



That portion of a coastal stream influenced by 

 the tide of the body of water into which it 

 flows; a bay, at the mouth of a river, where 

 the tide meets the river current; an area 

 where fresh and marine waters mix. (See 

 Positive Estuary , Inverse Estuary , Neutral 

 Estuary , Coastal Zone ) 



EULITTORAL ZONE 



(Tidal Zone) 



EUPHOTIC ZONE 



The lighted region of a body of water that 

 extends vertically from the water surface 

 to the depth at which photosynthesis fails 

 to occur because of insufficient light 

 penetration. 



EURY- 



Prefix meaning wide; e.g., euryhaline refers 

 to a wide range of salienty tolerance; 

 eurythermal refers to a wide range of 

 temperature tolerance. (See Steno- ) 



EUTROPHIC LAKES 



Lakes which are rich in nutrients and organic 

 materials, therefore, highly productive. These 

 lakes are often shallow and seasonally deficient 

 of oxygen in the hypolimnion . (See Oligotrophic 

 Lakes) 



