Subsurface viruses and bacteria in Holocene/Late Pleistocene sediments of Saanich Inlet, BC: ODP Holes 1033B and 1034B, Leg 169S

✍ Scribed by D.F. Bird; S.K. Juniper; M. Ricciardi-Rigault; P. Martineu; Y.T. Prairie; S.E. Calvert

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 414 KB
• Volume: 174
• Category: Article
• ISSN: 0025-3227
• DOI: 10.1016/s0025-3227(00)00152-3

✦ Synopsis

Little is known of long-term processes affecting microbial abundance in buried marine sediments. In collaboration with geochemists and sedimentologists involved in ODP Leg169S, we undertook a study of bacterial and viral abundance throughout the entire Holocene sediment section in Saanich Inlet, British Columbia, Canada. Sediments were sampled at 1.5-m intervals from the sediment surface down into Pleistocene sequences at depths of .100 m. Preparations of formalin-®xed sediment were stained with the nucleic acid stain Yo-Pro and bacteria and viruses were enumerated using epi¯uorescence microscopy. Viral presence was con®rmed by electron microscopy. More widely spaced measurements of adenosine triphosphate (ATP) and the biogenic pore water gases H 2 , CH 4 and CO were used as indices of microbial metabolic activity. Bacterial and viral abundances were high (.10 9 gdw 21 ) in these organic-rich sediments relative to oceanic areas, and were highly correlated, indicating a probable close functional dependence characteristic of predator±prey relations. The upper Holocene section showed a signi®cant subsurface peak in microbial abundance that was correlated negatively with sediment organic matter content, but corresponded with biogenic gas accumulation. The interpretation of these and other signi®cant trends is discussed in relation to the Holocene/late Pleistocene history of organic matter sedimentation and diagenetic processes.