Evaluating PAH biodegradation relative to total bacterial carbon demand in coastal ecosystems: Are PAHs truly recalcitrant?

Document Type

Book Chapter

Date of Original Version



Various techniques have been used to evaluate microbial metabolic activity in natural environments. In recent years, tracer additions of radiolabeled substrates coupled with short term, environmentally-relevant incubation experiments have become standard for assessing overall microbial growth rates as well as utilization rates for specific components of the bioavailable carbon pool. Using these techniques, microbial activities have been determined over a wide range of spatial and temporal scales in a variety of estuarine settings, providing valuable insight into carbon cycling in these dynamic systems. In this paper, we focus on patterns of microbial carbon consumption in estuarine sediments and relate these to the utilization of polyaromatic hydrocarbons (PAHs) as a recalcitrant, yet microbially available component of the carbon pool. Drawing on extensive field studies and those published in the literature, we relate microbial metabolic activities to the utilization of specific carbon species, discuss the partitioning of carbon between bacterial production and respiration (utilization efficiency), address the substrate-activity relationship for utilization of recalcitrant organic carbon and identify seasonal effects on the utilization of natural and anthropogenic carbon pools. These studies elucidate the advantages, disadvantages and caveats of relating microbial consumption of bulk labile organic carbon to the utilization of specific components and improve our ability to predict the fate of organic contaminants in estuarine systems. © 2008 Nova Science Publishers, Inc. All rights reserved.

Publication Title, e.g., Journal

Microbial Ecology Research Trends

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