OVERVIEW OF THE BIOGENIC AND ANTHROPOGENIC HYDROCARBON 



DISTRIBUTIONS IN SEDIMENTS ALONG 



THE NORTH ATLANTIC MARGIN 



Dr. Paul D. Boehm 

 Batten e Ocean Sciences 

 Duxbury, MA 



Georges Bank and the adjacent slope, rise, and submarine canyon areas are 

 characterized by highly dynamic sediment transport, deposition, and 

 resuspension cycles. Important questions concerning the hydrocarbon story for 

 this area are: 



■ What are the overall concentrations of hydrocarbons in the sediments? 



■ What is the composition of the hydrocarbon assemblage? 



■ What is the distribution of both total hydrocarbons and individual 

 hydrocarbons? 



■ What are the sources and sinks of hydrocarbons? 



■ What processes control distributions and concentrations? 



HYDROCARBON DISTRIBUTION 



Results of five MMS, National Oceanic and Atmospheric Administration 

 (NOAA), Bureau of Land Management, and Department of Energy studies show that 

 pollutant and biogenic hydrocarbons distributions follow the general trends of 

 those for fine sediments. Total hydrocarbons and polycyclic aromatic 

 hydrocarbons (PAH) are found at very low levels in the central bank area where 

 sediments are coarse. Total hydrocarbon values are 0.5 to 5 ppm for Georges 

 Bank with PAH values of 5 to 20 ppb. Elevated levels are found in the 

 depositional areas of the "mud patch" on the shelf south of Martha's 



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