EPA Science Inventory

SEDIMENT TOTAL ORGANIC CARBON: IS THIS A USEFUL INDICATOR OF SEDIMENT CONDITION FOR PACIFIC NORTHWEST ESTUARIES?

Citation:

Nelson, Walt AND M. Frazier. SEDIMENT TOTAL ORGANIC CARBON: IS THIS A USEFUL INDICATOR OF SEDIMENT CONDITION FOR PACIFIC NORTHWEST ESTUARIES? Presented at Pacific Estuarine Research Society, Newport, OR, April 03 - 05, 2014.

Description:

Total organic carbon (TOC) content of sediments has been used as an indicator of benthic community condition during multiple cycles of the EPA National Coastal Assessment (NCA). Because percent TOC is generally positively correlated with sediment percent fines, previous analyses have shown that an uncorrected TOC index will substantially overestimate potentially impacted sites. Within the Pacific Northwest region, individual estuaries differ significantly in the regression slopes that relate TOC to grain size, and estuary classification has so far failed to provide insight into the drivers of this variation. Within an individual estuary, the spatial variation in depositional versus erosional conditions may drive the relationship. Given the multiple sources of variation, we conclude that TOC is currently not a useful indicator of marine benthic condition in estuarine condition assessments.

Purpose/Objective:

Total organic carbon (TOC) content of sediments has been used as an indicator of benthic community condition during multiple cycles of the EPA National Coastal Assessment (NCA). TOC is generally positively correlated with sediment percent fines, such that an uncorrected TOC index will substantially overestimate potentially impacted sites. Within the Pacific Northwest region, individual estuaries differ significantly in the regression slopes that relate TOC to grain size, and estuary classification has so far failed to provide insight into the drivers of this variation. Within an individual estuary, the spatial variation in depositional versus erosional conditions may partly the relationship. Given the multiple sources of variation, we conclude that TOC is currently not a useful indicator of marine benthic condition in estuarine condition assessments

URLs/Downloads:

ABSTRACT - NELSON.PDF   (PDF,NA pp, 40.352 KB,  about PDF)

Record Details:

Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Completion Date: 04/07/2014
Record Last Revised: 04/07/2014
Record Created: 04/07/2014
Record Released: 04/07/2014
OMB Category: Other
Record ID: 272735

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

WESTERN ECOLOGY DIVISION

PACIFIC COASTAL ECOLOGY BRANCH