The total number of eggs and the frequency of eggs, showing either 

 abnormal development or no differentiation at all, were noted. 



6.2.3 Meiofauna 



Meiofauna was sampled using an Askci core sampler (described in 



Appendix 1 in Ankar and Elmgren, 1976). Generally 5 core samples of 



2 

 3.9 cm and at least 7 cm length were obtained at each station, but only 



3 have been sorted. Sediment cores were preserved whole in 4% formalde- 

 hyde solution buffered with hexamine and with Rose Bengal added to stain 

 the animals (see Dybern et al., 1976). Further treatment also followed 

 BMB recommendations (Dybern et al., 1976) i.e. meiofauna was delimited 

 by a 1 x 1 mm metal mesh sieve as the upper limit (to exclude macrofauna), 

 and by a 40 x 40 (.mi metal mesh sieve as the lower limit, with inter- 

 mediate 500, 200 and 100 pm sieves used to facilitate sorting, sub- 

 sampling and biomass estimation. 



Each composite sample was first sieved through 1 and 0.5 mm sieves, 

 and then split into light and heavy fractions by repeated decantation 

 (as in Elmgren, 1973). Before sorting, the light fractions were sieved 

 through a 200 (Jm sieve and then subsampled as follows (in a sample 

 splitter according to Elmgren, 1973 "sample divider"): 100 (jm fraction 

 1/8, 40 |jm fraction 1/64. The finest light fraction (40 pm) was soni- 

 fied (Thiel et al., 1975) for 25 seconds before sorting. The heavier 

 fractions were sieved through a 100 |jm sieve (generally after sonifi- 

 cation) and the retained fraction sorted in its entirety. The finest 

 heavy fraction was discarded since earlier checks have shown it to be 

 virtually devoid of animals (Elmgren et al., 1979). 



Samples for counts of dead and live ostracods were collected on 17 

 February and 9 March at Stations 15 and 20, using the Ockelmann dredge, 

 and subsequently sieved through a 500 (Jm sieve before sorting and count- 

 ing. 



6.3 Results 



6.3.1 Sediment samples 



No oil hydrocarbons which could be identified as Tsesis oil could 

 be found in any of the sediment samples (see section 11). The results 



101 



