Section Page 



Light micrograph of Scenedesmus sp. stained for poly- 

 phosphates by the technique of Ebel et al- (1958) .... 180 



Light micrograph of Fragilaria crotonensis Kitton 

 stained for polyphosphate by the technique of Ebel 

 et ai. (1958) 180 



Transmission electron micrograph of cytologically normal 



Plectonema boryanum 183 



Transmission electron micrograph of Plectonema boryanum 



treated with 0.1 yg - at/S, Pb 183 



Transmission electron micrograph of Plectonema boryanum 



treated with 0.1 yg - at/Jl Zn 183 



The dynamics of the survival rate of salmon larvae 192 



The dynamics of the survival rate of roach 195 



Distribution of benthos and cesium-137 in a core from 

 Lake Erie 204 



The radiotracer scanning system 206 



The actual and measured distribution of activity from a 



submillimeter line source 207 



15 Effect of tubificid worms on the distribution of cesium- 

 137 208 



15 Location of the peak activity versus time 



209 



15 Effect of amphipods ( Pontoporeia hoyi ) on the distribu- 

 tion of cesium-137 210 



15 Time-dependence of the optics-corrected activity profile 



width 211 



15 Effect of adding very high levels of NaCI on the rate of 

 sediment reworking by the Oligochaete worm, Limnodrilus 

 hoffmeisteri 213 



15 Response of the sediment reworking rate to additions of 



sulfate (Na2S04) for two species of Oligochaete worms . . 214 



15 Activity of cesium-137 and sodium-22 in a control cell 

 and in a cell with tubificid worms after an elapsed 

 time of about 200 hours 216 



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