4.3.4 Zooplankton 



The ciliate biomass shoved no consistent differences between the 

 stations (Fig. 4.6). The net zooplankton biomass (Fig. 4.7) did not 

 diverge from the reference stations, except very near the tanker (sta- 

 tion II) in the days immediately following the spill. The zooplankton 

 community was mainly composed of copepods ( Acartia spp., E urytemora sp. 

 and Temora longicornis) and rotifers (mainly from the genus Synchaeta ) . 

 No changes in the genus or species composition or in the developmental 

 stages of copepods could be found. 



The zooplankton was found to be contaminated with oil droplets. 

 Oil was mostly observed adhering to the furca or the feeding appendages 

 but was also found in the gut. Approximately 50% of the net zooplankton 

 was contaminated during the first weeks after the grounding. After 

 three weeks about 20°/ o were still contaminated. 



4.3.5 Sedimentation 



The amount of sedimented matter in the impacted area is shown in 



Table 4.2, and was relatively high during the first weeks after the 



-2 -1 

 spill, 6-9 g dry weight m d . From mid-November on, rates 



-2-1 

 were decidedly lower, 3-4 g dry weight m d . At reference station VI, 



rates were somewhat lower at the beginning of November but higher at the 



end of the investigation period. 



Calculations based on the results from the oil analysis shown in 



Table 4.2, Fig. 4.8, show the amount of oil sedimented per square meter 



per day. The high amount of oil found in sedimented matter also at 



station IV, located more than 2.5 km upwind of the tanker, is notable. 



70 



