Can sediment total organic XXXX and grain size be used to diagnose organic enrichment in estuaries?

@entity505 @entity26 @entity137 @entity21364
Eutrophication (i.e., nutrient enrichment, organic enrichment, and @entity26 depletion) is one of the most common sources of impairment in Clean Water Act 303(d)-listed waters in the United States. Although eutrophication can eventually cause adverse effects to the benthos, it may be difficult to diagnose. Sediment organic @entity505 (OC) content has been used as an indicator of enrichment in sediments, but the amount of surface area available for @entity505 adsorption must be considered. We investigated the utility of the relationship between OC and sediment grain size as an indicator of eutrophication. Data from the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program was used to test this relationship. However, anthropogenic contaminants are also capable of causing adverse effects to the benthos and often co-occur with elevated levels of OC. Contaminant analysis and @entity137 tests were not consistently related to enrichment status as defined by relationship between total OC and grain size. Although variability in response occurred, reflecting the variance in the water column factors (dissolved @entity26 , @entity21364 , and nutrients) and limited sample sizes, the data supported the hypothesis that sites designated as enriched were eutrophied. Dissolved @entity26 levels were reduced at enriched sites, whereas @entity21364 and nutrients were higher at enriched sites. This suggests that the relationship of OC to grain size can be used as a screening tool to diagnose eutrophication.
