than station 20. Samples from March, June and August 1978 have been 

 sorted and this station has been followed intermittently since 1971. 

 Pre-spill samples from further sampling occasions are available from all 

 stations, but could not be sorted within the budget available. 



As is normal in fine sediments, nematodes totally dominated the 

 meiofauna abundance at all stations and sampling occasions (Fig. 6.10 - 

 6.13). Except for an exceptionally low nematode value at Station 20 in 

 March 1978 there were no statistically significant differences in nematode 

 abundance between the stations. It is perhaps worth noting that the 

 proportion of large nematodes was consistently higher at Station 20 than 

 at Station 15 during the post-spill period. 



The ostracods often constitute the larger part of the meiofauna 

 biomass in deeper Baltic soft bottoms (c.f. Ankar and Elmgren, 1976, for 

 the Asko area), even though they are much less numerous than the nema- 

 todes. At both station 21 (November 1976 pre-spill) and station 15 



(post-spill reference station) moderate to high ostracod numbers were 



4 2 

 found (5-17 x 10 ind/m ) whereas station 20 had very low ostracod 



4 2 

 abundances on all post-spill sampling occasions (1-3 x 10 ind/m ). 



(See Fig. 6.11) . 



The rest of the meiofauna comprises a wide assortment of taxa , such 

 as Foraminifera , the hydroid Protohydra leukartii, Turbellaria, Kinorhyncha, 

 harpacticoid copepods and juvenile macrofauna (so-called temporary 

 meiofauna - mostly Macoma balthica , Harmothoe sarsi and Halicryptus 

 spinulosus larvae, but part of the year also juvenile Pontoporeia spp . ) . 

 Each single group was too scarce in the samples for definite trends to 

 be observed, but as an aggregate all these "others" (total meiofauna 

 excluding nematodes and ostracods) showed a much lower abundance at 

 station 20 (post-spill) than at stations 21 (pre-spill) and 15 (post-spill 

 reference) (See Fig. 6.14). 



The Ockelmann dredge samples collected in February and March showed 

 a much higher proportion of live ostracods in relation to total ostracods 

 (live + "recently" dead) at station 15 than at station 20, where only 

 few live specimens were found (see Fig. 6.13). The difference between 



the stations was highly significant on both occasions (p < 0.0001, 



2 

 X -test). 



113 



