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doi:10.2204/iodp.proc.336.201.2013 Data report: total cell counts and qPCR abundance of Archaea and Bacteria in shallow subsurface marine sediments of North Pond: gravity cores collected during site survey cruise prior to IODP Expedition 3361Anja Breuker2 and Axel Schippers2IntroductionThe total number of prokaryotes in deeply buried marine sediments decreases with sediment depth and varies over orders of magnitude in different areas of the ocean. It is mainly controlled by the content of organic carbon in the sediment as the microbial substrate (Parkes et al., 1994; D’Hondt et al., 2004; Schippers et al., 2005, 2012; Edwards et al., 2012; Kallmeyer et al., 2012; Lomstein et al., 2012; Hoehler and Jørgensen, 2013). Organic-lean, oligotrophic, and oxic sediments of the Pacific host oxygen-respiring prokaryotes (Røy et al., 2012). Specific archaeal communities for sediments with different trophic states could be detected (Durbin and Teske, 2012). An open question is if Bacteria or Archaea dominate in oligotrophic sediments as previously discussed for eutrophic sediments based on quantitative polymerase chain reaction (qPCR) analysis (Schippers et al., 2005, 2012). Similar to oligotrophic Pacific sediments, oligotrophic (total organic carbon = ~0.15% ± 0.07%) and oxic sediments from the North Pond area in the 7 m.y. old western flank of the Mid-Atlantic Ridge at 23°N have been shown to contain molecular oxygen downhole to >8 m sediment depth. Aerobic respiration likely dominates organic carbon oxidation (Ziebis et al., 2012). During a site survey cruise prior to Integrated Ocean Drilling Program (IODP) Expedition 336 to North Pond, sediment cores were collected to 8 meters below seafloor (mbsf). We sampled these cores to count total cells and determine the abundance of Bacteria and Archaea by qPCR using modified protocols. |
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