The absence of Stage III seres from some stations may be 

 related to the presence of relic overconsolidated sediment at depth 

 (Figure 3-37) . This sediment may: 1) inhibit burrowing by Stage III 

 taxa and 2) be low in nutrients for detritivores. The aggregate 

 successional status of the STNH-S mound was much lower than that at 

 the new CLIS reference station, where 18 replicates out of 20 (90%) 

 showed Stage III seres to be present. 



The freguency distribution of OSI values ranged from +4 to 

 +11 with a major mode at +7 (Figure 3-38) . Stations 200W and 200NW 

 have again been deleted from this distribution due to their anomalous 

 stratigraphy. These OSI values were not significantly different from 

 the August 1985 data set (p = 0.84, Mann-Whitney U-test) ; however, 

 they were significantly lower than those calculated for the new CLIS 

 reference station (p = 0.0209). Areas of the STNH-S disposal mound 

 where OSI values were less than 6 were stations 400W, 200SW, and 600S 

 (Figure 3-41) . This was generally the area of low OSI values mapped 

 in August 1985. The low OSI values on the west side of the STNH-S 

 mound may be related to the presence of relic, overconsolidated 

 sediment which may impede burrowing by infauna. This sediment may 

 also be devoid of labile organic matter, which would sustain deposit 

 feeders. Alternatively, this sediment may contain toxic compounds 

 which has kept this area in an anomalously low successional status. 

 In order to determine the probable cause for this low OSI condition, 

 further study would be necessary. 



3.3.4 Cap Sites One (CS-l) and Two (CS-2) 



The Black Rock Harbor sediment at Cap Site 1 was covered 

 with silt from the upper portion of New Haven Harbor in May 1983. 

 REMOTS® surveys performed immediately following capping found that 

 the cap material was visually indistinguishable from the underlying 

 sediment, precluding an accurate estimate of cap thickness (SAIC, 

 1984) . The REMOTS® surveys did show that the entire deposit (Black 

 Rock Harbor sediment plus cap material) had a thickness in excess of 

 10 cm in a 150 to 200 meter radius around the mound center. The 

 thickness decreased from 10 cm to cm within about a 400 meter radius 

 of the mound center. 



In the July 1986 survey, the CS-l stations had a grain- 

 size major mode of > 4 phi (silt-clay) with the exception of station 

 600N, which had a major mode of 3-2 phi (fine sand) (Figure 3-42). 

 Station 600N is located on the flank of CS-2; this sand apparently 

 represented capping material deposited at CS-2. This extension of the 

 sand cap at station 600N was also noted in the August 1985 survey. 

 Minor modes of medium, fine, and very fine sand were present near the 

 surface of several stations. The origin of this sand may be related 

 to the winnowing of fines or to the broad dispersal of sand from 

 nearshore erosion during Hurricane Gloria in September 1985. The 

 post-hurricane REMOTS® survey conducted on October 28, 1985 showed the 



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