133 



Station Selection - Due to complexity of region, true controls and treatments are not possible. 

 However, contaminant distributions and placement within natural gradients can be employed to 

 designate stations least likely to reflect various influences. 



Components Relating Process to OCS Impacts 



Control sites compared to probable locations of OCS impacts based on contamination accumulation, 

 growth rates of ubiquitous and/or abundant key species, how close community metabolism is coupled 

 to organic input (cohort analysis; role of disturbance), and experimental studies on the effect of 

 predation on structuring community production and biomass. 



• Links to Physical Oceanography - Determine importance of four mesoscale forcing functions for: 



nutrient inputs from the Mississippi-Atchafalaya River plume and coastal boundary current; 



upwelling of "new" nitrogen from interaction of loop current eddies with shelf upper slope 



topography; 



upwelling of "new" nitrogen at other thermohaline surface fronts/mixing zones (e.g., bottom layers); 



and, 



response to storms. 



• Analysis and Synthesis 



development of a Modeling Component - Systems models must be developed to test via simulation 

 interrelations amongst system parameters. Such an effort must be initiated prior to adoption of final 

 field design. 



development of a Process Data Base - Build a data base for primary productivity and benthic 

 community structure, relating natural gradients, storms and disturbances, and temporal salinity 

 development to biological processes. 



4.2.2 Detection of Chronic Stresses 



The Detection of Chronic Stresses Workshop met its charge of considering the design of studies to detect the 

 results of low-level chronic stress at oil and gas sites that had been in operation a long time. Previous studies 

 to accomplish this have found only acute and spatially restricted impacts in the immediate vicinity of platforms. 

 Beyond a few hundred meters from a platform, techniques used were unsuited for detection of impacts against 

 a background of considerable natural variation. 



An important outcome of the workshop was the realization that potential low-level chronic stresses must first 

 be very well defined and then appropriate designs employed. Simply repeating the surveys of the past will prove 

 fruitless. Of special importance is the incorporation of new field and analytical technologies to better search for 

 the type of impact being tested. 



Elements of a possible study could consist of the following: 



Primary Processes 



chronic toxicology of contaminants 

 geochemical behavior of toxins 

 bioaccumulation 



Faunal Based Components 



toxicology on selected species 



composition of benthic and biofouling fauna 



traditional indicators of biological status of the organisms (growth, recruitment, etc.) 



