reexamination of this dune field indicated movement by a number of 

 the dunes over a 2-year span, allowing one of the first estimates of 

 mass flux for transported deep-sea sediments. 



Although complicated by the need for fine-scale observational 

 techniques, investigation of the erosion and transport of deep-sea 

 sediments will be an important field of research in coming years. 

 With increasing use of the continental shelves, the need to 

 understand sediment transport in these regions has been increasing- 

 ly recognized. In a USGS program along the coasts of Spain, Florida, 

 Washington, and Oregon, consistent patterns of ripples and 

 associated bed forms have been related to the dynamics of bottom 

 orbital water velocities associated with shoaling waves, and to 

 sediment grain size. 



The USGS has also examined modern sedimentation processes off 

 the northern coast of Alaska, where sea ice is a dominant agent. A 

 shear zone develops during the winter between the grounded ice that 

 forms near shore and the floating pack ice offshore. Examination of 

 the continental shelf sediments beneath this shear zone has shown 

 deep gouges and furrows produced by the grounded ice. The 

 processes that form bottom features will pose major problems for the 

 building of sea-floor structures along the Arctic coast of Alaska and 

 Canada. 



NOAA's shelf-dynamics program is attempting to quantify the 

 pattern (rates and directions) of sediment erosion, transport, and 

 deposition on continental shelves. Such information is essential for 

 resolving the conflicting human uses of the shelf surface. The prime 

 area of study is the New York Bight, which is presently suffering 

 from environmental impact problems (primarily due to waste 

 disposal practices) that will be common to most shelves by the turn 

 of the century. 



The program is twofold, investigating both sand and suspended 

 fine sediment transport. The flux of suspended sediment across the 

 New York Bight is being examined by means of water sampling, and 

 optical and sonic sensing techniques. Studies indicate that the 

 voluminous quantities of sewage sludge dumped into the Bight do 

 not settle immediately to the bottom, but become a component of the 

 natural fine-sediment transport system. Calculations show that a 

 single storm may resuspend fine sediments from the bottom and 

 generate a natural suspended sediment load equivalent to weeks of 

 sewage sludge dumping. 



Sand transport in the New York Bight Apex is being estimated by 

 computations based on near-bottom current-meter records, and 

 independently, by means of mapping the growth of radioisotope 

 sand tracer dispersal patterns. Studies are presently concentrated 

 on the inner shelf where determinations of sea-floor stability are 



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