(Table T1) Total procaryotes, and living bacteria and archaea in black shales of ODP Leg 207 sites

Subseafloor sediments harbor over half of all prokaryotic cells on Earth (Whitman et al., 1998). This immense number is calculated from numerous microscopic acridine orange direct counts (AODCs) conducted on sediment cores drilled during the Ocean Drilling Program (ODP) (Parkes et al., 1994, doi:10.1038/371410a0, 2000, doi:10.1007/PL00010971). Because these counts cannot differentiate between living and inactive or even dead cells (Kepner and Pratt, 1994; Morita, 1997), the population size of living microorganisms has recently been enumerated for ODP Leg 201 sediment samples from the equatorial Pacific and the Peru margin using ribosomal ribonucleic acid targeting catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) (Schippers et al., 2005, doi:10.1038/nature03302). A large fraction of the subseafloor prokaryotes were alive, even in very old (16 Ma) and deep (>400 m) sediments. In this study, black shale samples from the Demerara Rise (Erbacher, Mosher, Malone, et al., 2004, doi:10.2973/odp.proc.ir.207.2004) were analyzed using AODC and CARD-FISH to find out if black shales also harbor microorganisms.

海底沉积物承载着地球上超过半数的原核细胞（Whitman等，1998）。该庞大数值通过对大洋钻探计划（Ocean Drilling Program，ODP）期间获取的沉积岩芯开展的大量显微吖啶橙直接计数法（acridine orange direct counts，AODCs）计算得到（Parkes等，1994，doi:10.1038/371410a0；2000，doi:10.1007/PL00010971）。由于此类计数无法区分活体细胞、失活细胞甚至死细胞（Kepner与Pratt，1994；Morita，1997），近期有研究针对取自赤道太平洋与秘鲁陆缘的大洋钻探计划201航次（ODP Leg 201）沉积样品，采用靶向核糖体核糖核酸（ribosomal ribonucleic acid）的催化报告基因沉积-荧光原位杂交（catalyzed reporter deposition-fluorescence in situ hybridization，CARD-FISH）技术，对活微生物的种群规模进行了计数（Schippers等，2005，doi:10.1038/nature03302）。即便在年代极为久远（16 Ma）且埋藏深度极大（>400 m）的沉积物中，仍有相当比例的海底原核生物处于存活状态。本研究对取自德梅拉拉海隆（Demerara Rise）的黑色页岩样品（Erbacher、Mosher、Malone等，2004，doi:10.2973/odp.proc.ir.207.2004）开展了吖啶橙直接计数法与催化报告基因沉积-荧光原位杂交分析，以探究黑色页岩中是否也栖息着微生物。