Depth Profile of Bacterial Metabolism and PAH Biodegradation in Bioturbated and Unbioturbated Marine Sediments.

摘要

Bacterial mineralization of polycyclic aromatic hydrocarbons (PAH) to carbon dioxide is known to occur most rapidly in highly aerated microenvironments. Bioturbation of marine sediments by benthic microfauna has the potential to increase both rate and depth of bacterial PAH mineralization by recirculating oxygenated bottom water into sediment burrows. We measured heterotrophic bacterial production and mineralization of PAHs in sections of sediment cores sampled from two stations in an urbanized waterway feeding San Diego Bay. Heterotrophic bacterial production was twofold higher in cores with greater bioturbation depth and was much higher in the top 2 cm of both cores. PAH mineralization was higher in the top 12 cm of the core from the bioturbated station (P04) relative to the less bioturbated station (P17). The depth of bioturbation by the benthic macrofaunal and meiofaunal assemblage may be an important factor in selecting for PAH-degrading bacterial assemblages in impacted sediment. This synergistic relationship may be an important determinant in the natural recovery rate of hydrocarbonimpacted marine sediments.