Composition and Distribution of Macrobenthic Invertebrate Fauna 



11 



Ge s" "slope 



■V- 



-&- 



-V 



Figure 5 



Chart of the study area showing the location of the six standard geographic subareas used for analytical 

 purposes: Nova Scotia, Gulf of Maine, Georges Bank, Georges Slope. Southern New England Shelf, and 

 Southern New England Slope. 



(1966); Schopf (1967); and Schopf and Colton (1966); 

 and Mountain and Holzwarth (1989). 



Sediment Organic Carbon 



Organic carbon in bottom sediments was measured by 

 gasometric method in samples after removal of CaCO, 

 by acid treatment. Data are contained in Hathaway 

 (1971). 



Description of the Region 

 Topography 



Relief of the sea bottom off the New England region 

 has been studied most recently by the U.S. Geological 

 Survey and the Woods Hole Oceanographic Institution 

 (Austin et al., 1980; Emery, 1965a, 1966b; Emery and 

 Ross, 1968; Emery and Uchupi, 1972; Gibson et al. 

 1968; Klitgord and Behrendt. 1979; Klitgord et al.. 1982. 

 Schlee et al., 1976; Sheridan, 1974; Uchupi, 1965b, 



1966a, 1966b. 1966c, 1968; Uchupi and Emery, 1967; 

 Uchupi et al.. 1977; Uchupi and Austin, 1979; Valen- 

 tine, 1981). Figure 6 is based on, and has been derived 

 from, a much larger more detailed chart by Uchupi 

 (1965a), U.S.G.S. Map 1-451, scale 1:1,000,000. 



Topographically, the New England offshore area con- 

 sists of several large, grossly different geological fea- 

 tures. The largest and most complex feature is the Gulf 

 of Maine, an immense, nearly oval-shaped glacially 

 eroded depression on the continental shelf. The topo- 

 graphy in this depression is very irregular, resulting in 

 numerous basins separated l>\ i idges. swales, and banks. 

 These topographic irregularities are due in part to 

 deposition, gouging, erosion, and related actions dur- 

 ing the Pleistocene period of glaciation. Greatest depth 

 in the gulf is 377 m, in Georges Basin; shallowest off- 

 shore depth in the gulf is 9 m, at Amen Rock on Cashes 

 Ledge in the west central part of the Gulf of Maine (see 

 Ballard and Uchupi, 1975; Austin et al., 1980; Klitgord 

 et al., 1982; Schlee et al., 1976). 



Georges Bank is another striking topographic fea- 

 ture. It is an enormous (120 km by 240 km) submarine 

 cuestalike bank situated at the mouth of the Gulf of 



