have uniformly high OSI values of +11 and were significantly 

 greater than disposal site stations (p<0.05, Mann-Whitney). 



3.3 Benthic Sampling 



A total of 14 8 taxa were found in the benthic samples 

 taken at stations 1, 13, 20, 22, 23, and 24 from the disposal site 

 and from the reference stations Rl, R2 , and R3 . The largest number 

 of taxa (67, 45 % of the total fauna) were polychaetes, followed by 

 molluscs (35 taxa, 24 %) and crustaceans (29 taxa, 20 %) . Other 

 major taxonomic groups, such as cnidarians, nemerteans, 

 echinoderms, and tunicates, contributed only small percentages to 

 the total fauna. 



The total number of species was between 4 and 65 per 

 station at the disposal site and between 45 and 71 per station at 

 the reference areas. Densities were between 4,800 and 9,800 

 individuals per m 2 on the disposal mound, with the lowest density 

 found at station 1 and the highest density found at station 22. 

 Densities at the reference stations ranged from 5,100 to 9,400 

 individuals per m 2 . The top 10 species by station were defined by 

 only 25 of the 148 taxa constituting the total fauna (Table 3-1) . 

 The polychaete Mediomastus ambiseta ranked first at all disposal 

 site stations and the reference station Rl; at reference stations 

 R2 and R3 , it ranked second and third, respectively. Another 

 polychaete, Ninoe nigripes , was also found at all stations, ranking 

 between 2 and 9. Other taxa present at all disposal mound 

 stations, but not all reference stations, were Oligochaeta and the 

 nemertean Tubulanus pellucidus . 



Stations 1, 20, 22, 24, and Rl clearly were dominated by 

 Mediomastus ambiseta ; the species contributed between 30 and 44 

 percent of the total number of individuals. Other top ranked 

 organisms were Oligochaeta (stations 1, 20, 24, and Rl) , the 

 polychaete Aricidea catherinae (stations 24 and Rl) , Ascidiacea 

 (stations 1 and 20) , the nemertean Tubulanus pellucidus (station 

 22) , and the mollusc Cylichnella bidentata (station 22) . Stations 

 23 and 13 were characterized by the polychaetes Mediomastus 

 ambiseta . Aricidea catherinae , Ninoe nigripes (station 23), and 

 Spiophanes bombyx (station 13) in the highest ranks, with 

 Mediomastus contributing only about 2 percent of the total number 

 of individuals. The reference stations R2 and R3 differed somewhat 

 from the other stations sampled for this program. At station R2 , 

 relatively high numbers of Ascidiacea were found, together with the 

 polychaetes Cirrophorus furcatus , Mediomastus ambiseta , and Ninoe 

 nigripes , each contributing 11 to 16 percent of the total number of 

 individuals. Station R3 was characterized by two molluscs 

 ( Cylichnella bidentata and Nucula proxima ) in high ranking 

 positions (1 and 3 out of the top 10) and only one polychaete 

 ( Mediomastus ) which ranked 2 out of the top 10. 



