High virus-to-cell ratios indicate ongoing production of viruses in deep subsurface sediments
High virus-to-cell ratios indicate ongoing production of viruses in deep subsurface sediments
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DOI：
10.1038/ismej.2013.245
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发表时间：
2014-07-01
期刊：
影响因子：
11
通讯作者：
Engelen, Bert
中科院分区：
文献类型：
--
作者：
Engelhardt, Tim;Kallmeyer, Jens;Engelen, Bert
海洋沉积物覆盖了地球三分之二的面积，并蕴藏着大量活的原核生物。由于有机碳来源微乎其微，本土微生物在地下深处的长期生存仍然是个谜。为了更好地了解微生物生命的控制因素，我们分析了全球分布的地下沉积物中的病毒丰度。通过电子显微镜在深部（海底以下 320 m）、古老（类似于 14 Ma 古老）和世界海洋最贫营养的地下沉积物（南太平洋环流 (SPG)）中检测到噬菌体。病毒数量（10（4）-10（9）cm（-3），通过落射荧光显微镜计数）通常随着沉积物深度的增加而减少，但总是超过细胞总数。大量的病毒表明它们作为海洋深层生物圈中原核生物死亡率的控制因素的影响。病毒与细胞的比率在更深和更贫营养的层中增加，在 SPG 的深层地下表现出高达 225 的值。大量噬菌体可能是由于沉积物基质的吸收和外酶降解的减少。然而，即使在最古老的沉积物中，微生物群落也能够维持病毒种群，表明病毒的持续生产，因此，病毒为海洋深层生物圈中的微生物生命提供了独立的指标。
Marine sediments cover two-thirds of our planet and harbor huge numbers of living prokaryotes. Long-term survival of indigenous microorganisms within the deep subsurface is still enigmatic, as sources of organic carbon are vanishingly small. To better understand controlling factors of microbial life, we have analyzed viral abundance within a comprehensive set of globally distributed subsurface sediments. Phages were detected by electron microscopy in deep (320m below seafloor), ancient (similar to 14Ma old) and the most oligotrophic subsurface sediments of the world's oceans (South Pacific Gyre (SPG)). The numbers of viruses (10(4)-10(9) cm(-3), counted by epifluorescence microscopy) generally decreased with sediment depth, but always exceeded the total cell counts. The enormous numbers of viruses indicate their impact as a controlling factor for prokaryotic mortality in the marine deep biosphere. The virus-to-cell ratios increased in deeper and more oligotrophic layers, exhibiting values of up to 225 in the deep subsurface of the SPG. High numbers of phages might be due to absorption onto the sediment matrix and a diminished degradation by exoenzymes. However, even in the oldest sediments, microbial communities are capable of maintaining viral populations, indicating an ongoing viral production and thus, viruses provide an independent indicator for microbial life in the marine deep biosphere.