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Influence of sediment organic carbon on estuarine benthic species of the US West Coast
Citation:
FRAZIER, M. R., H. LEE, II, AND W. G. NELSON. Influence of sediment organic carbon on estuarine benthic species of the US West Coast. Presented at 21st Biennial Conference of the Coastal and Estuarine Research Federation, Daytona Beach, FL, November 06 - 10, 2011.
Impact/Purpose:
Total organic carbon (TOC) is often used as an indicator of nutrient enrichment in estuarine environments.
Description:
Total organic carbon (TOC) is often used as an indicator of nutrient enrichment in estuarine environments. However, the determination of biologically relevant TOC criteria to indicate sediment quality is complicated by the relationship between TOC and grain size. Both variables independently influence species distributions, and thus estimates of species and community sensitivity to TOC may be confounded. We examined how common estuarine benthic infauna responded to sediment TOC after statistically controlling for sediment grain size using data from >1,400 benthic samples collected from Puget Sound, WA to Northern Mexico collected with a 9.1 m2 grab and 1-mm sieve. TOC ranged from 0 – 22%, with nearly 80% of the samples having 0-2% TOC. The probability of a species occurring in a sample was predicted from the percentage of fines (silt and clay) and TOC using splinal logistic regression models. The distribution of most common species was affected by percent fines; and about a third of these were affected by percent TOC. In addition to determining potentially detrimental TOC thresholds, this approach identifies species that are sensitive or tolerant to nutrient enrichment, which can be a key element for benthic indicator development.