(Linden, unpubl . ) • There is little doubt that the cold, stagnant bottom 

 waters of the Baltic, with low oxygen levels due to partial eutrophication 

 and a pronounced halocline, will slow the degradation of oil that reaches 

 the bottom below the halocline and cause it to be retained longer in the 

 sediments. In general, conditions could hardly be worse for repeated 

 oil spills. The chemical analysis of Macoma balthica has supported the 

 possibility that Tsesis oil has been deposited in reservoirs where it 

 degrades slowly and is, at times, resuspended. There are indications 

 that a slow accumulation of petroleum hydrocarbons in the sediments is 

 already a wide-spread phenomenon in the Baltic (Rudling, 1976). 



It may be important to note, especially when making comparisons 

 between the Tsesis experience and other oil spills, that the effect of 

 the Tsesis spill on the marine environment was seasonally dependent. 

 The spill occurred during what was probably the least critical of all 

 time periods both from the point of view of the aquatic biota and from 

 the point of view of human habitants (consequently there was less pres- 

 sure for short term remedial and cosmetic activity) . 



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