CHAPTER 10: LABORATORY STUDIES CARRIED OUT IN CONNECTION WITH THE SPILL 



10 . 1 Introduction 



In connection with the Tsesis oil spill some laboratory studies 

 were carried out on animals brought to the Asko laboratory from the 

 affected area. The reason for these investigations was to provide 

 information on possible sublethal effects of the oil on organisms in the 

 area . 



Three types of investigations were carried out: 



10.2 Respiratory measurements on the mussel Mytilus edul is . 



10.3 Measurements of byssus formation by Mytilus edulis . 



10.4 Burrowing behavior in the clam Ma coma balthica . 



10.2 Respiration measurements on the mussel Mytilus edulis 

 (Sture Hansson) 



The rate of energy turnover in organisms is known to be affected by 

 pollutants. One indication of oil-induced effects on the energy turnover 

 would be changes in the respiration rate. However, measurements of the 

 respiration rate alone cannot be used to determine how energy turnover 

 is affected as a number of other components in the budget might also be 

 affected, e.g., growth rate or food ingestion. 



10.2.1 Materials and methods 



Mussels were collected by SCUBA diving from the upper 3 m at oil 

 polluted littoral stations and from the same depth range at an unpolluted 

 reference station by means of a dredge from the shore. The mussels and 

 2 liters of the surrounding water were collected in ethylene containers 

 which were sealed underwater to avoid contamination by the surface oil 

 slicks . 



In the laboratory the mussels were allowed to acclimatize for 2-4 

 hours before the start of the experiment. The temperature during the 

 experiments did not differ by more than two degrees from that in situ , 

 and field temperature and salinity varied negligibly between stations. 



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