Bacterial Metabolism, Aromatic Biodegradation, and Lignin Biogeochemistry in Sediment Cores from Pearl Harbor, Hawaii
Formal rept. 1 Dec 2002-1 Nov 2003
NAVAL RESEARCH LAB WASHINGTON DC CHEMISTRY DIV
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Heterotrophic bacteria require a source of oxygen to rapidly metabolize complex and recalcitrant carbon sources like lignin, 2,4,6 trinitrotoluene TNT, and polycyclic aromatic hydrocarbons PAHs. The activities of burrowing macrofauna can increase oxygenation, which may stimulate bacterial metabolism of PAHs and heterotrophic production. We measured bacterial production, PAH mineralization, and lignin subunit concentration with depth in cores taken from South Loch and Bishops Point in Pearl Harbor, Hawaii. Bacterial metabolism decreased rapidly with depth but was much higher at South Loch than Bishops Point. PAH mineralization rates were higher at South Loch than at Bishops Point and extended down to the depths of bioturbation at each site upper 4 to 6 cm at Bishop s Point and upper 9 cm at South Loch. Phenolic moieties of lignin at South Loch and Bishops Point suggest there are different sources of organic matter to the two sites. PAH mineralization was elevated in bioturbated zones from both sites relative to those below this zone. Ambient PAH concentrations were also higher at the less bioturbated site. This is consistent with the hypothesis that benthic infauna stimulate PAH metabolism.
- Organic Chemistry
- Biological Oceanography