Surface sediments observed at all mounds were oxidized, 

 i.e., no large patches of anoxic sediments were present at the 

 sediment-water interface. Foraging activities of crustaceans, 

 movements of finfish and normal locomotive behavior of gastropods 

 in the area apparently have contributed to oxygenation of surface 

 sediments . 



Table 3-4 summarizes the relative abundances of species 

 identified during the dive transects. More detailed descriptions 

 of each mound follow. 



3.6.1 CS-1 



The survey dive was conducted in a 25 cm/sec (0.5 knot) 

 current. Horizontal visibility was approximately 1 meter. The 

 nepheloid layer was less than 1 cm. The substratum consisted of 

 fine-grained silt throughout. Large clumps of marsh peat, 0.5 - 

 0.7m diameter, were present at the pile center. Clumps were fouled 

 with hydroids, indicating they had been submerged and exposed for 

 some time. Megafauna utilized the clumps for shelter. Juvenile 

 cunner, Tautogolabrus adspersus , were observed on the lee side of 

 clumps. A single winter flounder, Psuedopleuronectes americanus . 

 was observed in a crevice, sheltered from the current. Lobsters, 

 Homarus americanus . and spider crabs, Libinia emarginata , were 

 observed in lobster traps on the mound. The sediment surface was 

 heavily tracked by crustaceans and finfish. Mud snails were 

 attracted to crustacean foraging excavations and whelk tracks. 



3.6.2 CS-2 



The survey dive was conducted in a 13 cm/ sec (0.25 knot) 

 current. The substratum consisted of a silt-sand matrix, 3 to 5 

 cm deep. Shell hash cover was approximately 3 0%, with some shell 

 material fouled by hydroids. The surface had irregular, small 

 ripples spaced at approximately 2 to 15 cm intervals. The sediment 

 surface was heavily tracked by crustacean and finfish activities. 

 Fecal mounds from infauna were common over the surface. Whelks, 

 hermit crabs, mud snails, sand shrimp, and mysids were the major 

 bioturbators observed. 



3.6.3 STNH-N 



The survey dive was conducted in a slight 5 cm/sec (0.1 

 knot) current. Horizontal visibility was 1.5 meters with low near- 

 bottom turbidity. The nepheloid layer was not visibly apparent. 

 The bottom consisted of fine silt (less than 1 cm deep) over coarse 

 sand over compacted clay. Small shell hash patches (less than 1 

 m diameter; Mulinia and Yoldia valves) covered less than 5% of the 

 surface sediment. Hydroids were occasionally anchored to shell 

 hash material. The topography of the survey area was flat with 

 vertical burrows into the sediment 1 to 10 cm diameter. Crustacean 

 foraging depressions were common, and several 15 cm diameter 



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