EFFECTS OF SIMULATED ENTRAINMENT 813 



the mortality values include lack of recovery of test animals after 

 exposure. 



In the long-term studies, 10 Daphnia were raised in 10-ml vials 

 until the fifth instar and then placed in 50-ml containers. The 

 animals v^ere fed and transferred into clean culture water daily. 

 Notes were made daily on mortality, physiological condition, 

 molting, presence or absence of eggs, number of live and dead young, 

 and incremental growth. Body size was measured with an ocular 

 micrometer from the head to the base of the spine in 0.1 -mm 

 increments. 



Oxygen consumption, filtering rate, ATP, aiid behavior measure- 

 ments were begun immediately after exposure to the stresses. The 

 number of replicates for each test are identified in the appropriate 

 tables. Oxygen consumption was measured by placing five unfed 

 organisms in each 60-ml respirometer containing aerated, dechlori- 

 nated water at 20° C. After 24 hr, the oxygen content was deter- 

 mined using the modified Winkler technique (American Public 

 Health Association, 1976) with a 0.005N^ thiosulfate solution. The 

 difference in oxygen content between experimental and control 

 organisms £ifter 24 hr was considered the amount of oxygen 

 consumed. 



Filtering rate was determined by placing three Daphnia in each 

 replicate containing 3.0 x 10^ gilgal cells/ml at 20°C. At and 24 hr, 

 algal concentration was determined with an Electrozone Celloscope 

 particle analyzer (Particle Data, Inc.). Filtering rate (F) was 

 determined by 



^ log Co — log Cf 



F = v— 5— ^ 5__L (1) 



loge 



where v is volume of water per animal, C„ is algal concentration at 

 time zero, and Ct is algal concentration after 24 hr. Data were 

 expressed as filtering rate (F) in milliliters per Daphnia per day. 



Levels of ATP were determined by boiling five exposed animals 

 per replicate in tris buffer and determining the ATP with the 

 luciferin— luciferase assay using a Lab-Line Instruments, Inc., 1940 

 photometer. 



Behavior was observed by placing 20 stressed animals into 50-cm 

 vertical columns and noting changes in the vertical distribution with 

 changes in light intensity from an incandescent bulb. 



T-tests were conducted on all experiments except the Daphnia 

 fed stressed and unstressed algae. For this study, a one-way factorial 

 analysis of variance was conducted, and differences were determined 



