are the system consumers, other in-situ oxygen-demanding materials 

 (natural seeps, deaths, excretion), the mainland (oxygen-demanding 

 materials in riverine and estuarine discharges, direct run-off and 

 erosion) , oxygen-demanding materials from offshore production 

 activities, and oxygen-demanding materials from marine transportation. 

 Planned future users include activities such as the Strategic Petroleum 

 Reserve (SPR) sites and offshore super tanker ports which will also 

 discharge oxygen-demanding materials. Even though any specific activity 

 may require only a small increment of the total capacity of the system, 

 and be insignificant as compared to the demand of other activities (such 

 as the natural system), only small, if any, increments may, in fact, be 

 available. If the requisite process information was available, 

 management plans could establish user priorities and meaningful 

 regulations could be instituted. For example, a minor improvement in 

 Mississippi River water quality resulting from regulatory actions might 

 greatly benefit the system, whereas a major technological improvement 

 required by regulation from a minor user (e.g. zero discharge of 

 oxygen-demanding materials by offshore production platforms) might 

 little benefit the system. 



What specific information is needed? This question probably could 

 best be addressed by attempting to develop an assimilative capacity 

 model for the Texas-Louisiana shelf ecosystem during the course of a 

 series of modeling workshops. The goal of the initial workshop would be 

 to bound the system in time and space, select indicators that would 

 reflect the health of the system in terms perceived important (e.g. 

 commercial shrimp landings, commercial and recreational red snapper 

 landings, coral standing crop, dissolved oxygen levels), develop process 

 submodels describing the dynamics of each system indicator and integrate 

 the submodels to provide a system model which concentrates on the system 

 components of most concern. As the conceptual process models for each 

 indicator were developed and translated to mathematical models, the 

 specific information and data needs required for making the assessments 

 would emerge. These needs could guide the planning of future research, 

 insuring that all information obtained would be directly useful for 

 environmental assessment purposes. Once the initial system model was 

 constructed, various development scenarios could be evaluated, and would 

 be based upon the best and most complete information available at the 

 time. 



After the initial workshop and following a period during which new 

 information could be gathered, a second workshop could be conducted 

 during which the model could be updated and revised based upon the 

 results of the new information. Ultimately, through a series of 

 information gathering periods and modeling workshops, a good model could 

 emerge — one with reasonable prediction capabilities. 



Several Federal and State agencies conduct and/or sponsor 

 environmental studies in the Gulf of Mexico in a complementary, but 

 little integrated fashion, due to the different mandates of various 

 agencies. The above-defined approach could provide a clearly defined 



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