Composition and Distribution of Macrobenthic Invertebrate Fauna 



53 



Figure 20 



Sand and gravel bottom at 194 m depth in the southwestern Cull oi Maine cast of Cape Cod. 

 Sediment contains some pebbles to 8 cm. Five large burrowing sea anemones (Coelenterata, 

 Ceriantharia) are visible. Camera tripping weight is at extreme right-renter. Photograph was 

 taken at station 1052, located at lat. 42°09' N.. long. 69°14' W. 



Relation to Sediment Organic Carbon 



Two general cause-and-effect relationships were con- 

 sidered in prompting the analysis of organic carbon 

 content in the sediments. The first was the possibility of 

 a high standing crop of benthic animals in areas of high 

 organic carbon, due to the probability of a greater food 

 supply in those areas; or secondly, the converse could 

 apply, namely that areas containing large standing crops 

 would he high in organic carbon due to biogenic activi- 



ties (fecal deposits, mortality, etc.). Regardless which 

 prevailed, high organic carbon content would be asso- 

 ciated with high abundance. 



The analysis did not reveal any clear-cut correlation 

 between sediment organic carbon content and benthic 

 faunal abundance. A few fannal groups exhibited good 

 correlations, some positive and some negative, but by 

 and large they were exceptional. 



Highest average densities (Tables 26, 27; Fig. 26) of 

 macrobenthos occurred in areas where the percentage 



