phosphorus), certain marine organisms, geologic subsidence and 

 other factors. Man-made changes in the wetlands which have 

 caused environmental stress include pollution from urban 

 runoff, industry, and pesticides; and channelization, drainage, 

 and filling of wetlands for urbanization, agriculture and 

 mining. All of these cause loss of habitat and productive 

 capabilities. Channeling and dredging in the marsh and 

 estuary areas are necessary for access to offshore and 

 onshore oil facilities, laying pipelines, and constructing 

 oil wells. As a consequence, various ecological changes 

 occur along with oil industry development (Mumphrey et al . , 

 1975: 41-95). 



Mumphrey et al . (1975: 86) list the following ecological 

 changes in coastal zones caused by channelization and 

 dredging by the petroleum industry: 



Interfering with sheet water flow through the 



marsh ; 



Allowing rapid salinity changes with the resultant 



death of vegetation and erosion of the marsh; 



Allowing destruction of marsh by wave action; 



Decreasing productivity by the presence of 



straight vs. sinuous channels that accelerate 



removal of freshwater and also confine water 



movement ; 



Destruction of barrier islands with resultant 



increased destruction of marsh. 



89 



