development of stressor-response relationships for individual stressors and will coordinate with 
these respective research groups in the development of diagnostic methods and models for 
individual stressors. The focus of each stressor-specific research area is outlined below in Table 
6, with the biological endpoints and spatial scale of investigation noted Gaps have been 
identified relating to the investigation of nutrient effects in freshwater streams and rivers, and the 
investigation of clean sediment effects on coastal wetlands and estuaries. Because these are 
significant stressors in the EPA Regions, biological scales and resource types of interest, the 
diagnostics work will have to be supplemented by work in other research areas or rely on 
Table 6. Single aquatic stressors method development covered by other research areas witiiin 
the Aquatic Stressors Framework {in italics = endpoints: biological scale (organism, 
population, community, ecosystem); spatial scale (habitat, water body, watershed, region)] 
Resource class 
Stressor 
Fresh Water 
Coastal & Lakes 
Fresh Water 
Watershed 
Marine Coastal 
Nutrients 
Community, 
Ecosystem 
Nutrient Group 
Organismal (SAV) 
Population (SA V) 
Community, 
Ecosystem, 
Watershed 
Nutrient Group 
Suspended and 
Bedded Sediments 
Habitat, community 
Organismal (SAV) 
Population (SAV) 
Habitat Alteration 
Population scale. 
Habitat Alteration 
Group 
Salmon populations. 
Habitat Alteration 
Group 
Shrimp populations. 
Habitat Alteration 
Group 
Toxic Chemicals 
Population level. 
Toxic Chemicals 
Group 
Population level. 
Toxic Chemicals 
Group 
Organismal, 
population, 
community. 
Toxic Chemicals 
Group 
existing literature to fill these gaps. In addition, the lack of effects work at the community level 
for many resource class/stressor combinations will need to be addressed, as this is the biological 
scale at which the States are assessing biological impairment in current monitoring programs. 
Other gaps have been identified by geographic region. Expertise available at AED and GED will 
be supplemented with expertise in watershed classification and assessment through collaboration 
with other research groups (e.g., MED or WED, USGS NAWQA program). Development of 
regional case studies or decision-support systems for the Pacific Northwest will require close 
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