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DISCRIMINATING THE BENTHIC EFFECTS OF ANTHROPOGENIC POINT SOURCES FROM SALINITY AND NITROGEN LOADING
Citation:
Johnson, R L., K T. Perez, E W. Davey, J A. Cardin, K J. Rocha, E H. Dettmann, AND J Heltshe. DISCRIMINATING THE BENTHIC EFFECTS OF ANTHROPOGENIC POINT SOURCES FROM SALINITY AND NITROGEN LOADING. Presented at Estuarine Research Federation National Conference, Seattle, WA, September 14-18, 2003.
Description:
To evaluate the influence of anthropogenic point sources on estuarine systems, environmental managers must be able to discern the level and effects of significant natural factors and nonpoint source inputs. We compared benthic community state, salinity and dissolved inorganic nitrogen (DIN) input from rivers in three Massachusetts estuaries. Two reference estuaries, Westport and Slocums, have no anthropogenic point source inputs; the test estuary, New Bedford, has multiple anthropogenic inputs. Benthic community states were compared using three indices. Only the similarity index statistically detected benthic community differences between all pairs of estuary benthic communities. Parametric tests showed that the average salinity at the average freshwater river flow was different in all three estuaries (29.4?, 24.3? and 28.8?). Estimates of conservative DIN, based on riverine input, were statistically different between Slocums (5.3 lM) and the other two systems (2.5 lM, Westport and New Bedford). We concluded that neither reduced salinity nor DIN can explain the benthic state in the test estuary and the most likely causes for this are past and/or present constituents from anthropogenic point sources. This comparative estuarine approach can provide an effective tool to assist environmental managers in appropriate allocation of resources for environmental remediation.