was affected (see Fig. 4.10). Using this area and the data presented in 

 Table 4.2, a total sedimentation of 19 tons of oil was calculated for 

 the period November 1 to December 21. Most probably this value under- 

 estimates the sedimentation since: 1) No data exist for the five days 

 immediately following the spill, probably the period with the highest 

 sedimentation rates; and 2) the affected area is certainly underesti- 

 mated, as not enough samples were taken for an adequate mapping. Thus 

 the true sedimentation is likely to be considerably higher, possibly in 

 the 30 to 60 ton range. 



4.5 Conclusions 



1. The effect on the pelagic system was moderate and of short duration - 

 within one month all measured parameters were essentially normal. 



2. Phytoplankton biomass increased in the contaminated area. 



3. Bacterial numbers increased in the contaminated area. 



4. Zooplankton were found to be heavily contaminated with oil. 



5. Sedimentation of oil to the benthos was calculated to be at least 



2 

 19 tons for an estimated affected area of 42 km (both numbers are 



minimum estimates). 



4.6 Acknowledgements 



The advice and support of Ulf Larsson, Asko Laboratory, during the 

 field work and the writing of this report are deeply appreciated and 

 thanks are due him and Ruth Hobro for placing unpublished results from 

 the Askb Laboratory's routine measurements from the reference stations 

 (I and VI) at the author's disposal. Dr. ftke Hagstrb'm, Department of 

 Microbiology, University of UmeS, provided practical help as well as 

 advice, without which none of the bacterial data could have been obtained. 



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