Linking geology, fluid chemistry, and microbial activity of basalt‐ and ultramafic‐hosted deep‐sea hydrothermal vent environments
Linking geology, fluid chemistry, and microbial activity of basalt‐ and ultramafic‐hosted deep‐sea hydrothermal vent environments
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DOI：
10.1111/gbi.12039
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发表时间：
2013-07
期刊：
影响因子：
3.7
通讯作者：
M. Perner;Moritz E Hansen;R. Seifert;H. Strauss;A. Koschinsky;S. Petersen
中科院分区：
文献类型：
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作者：
M. Perner;Moritz E Hansen;R. Seifert;H. Strauss;A. Koschinsky;S. Petersen
已知沿着沿着洋中脊穿过玄武岩的热液流体富含硫化物，而那些在超镁铁质地幔岩中循环的热液流体通常富含氢。因此，据估计，玄武岩承载系统中的最大能量是通过硫化物氧化获得的，而超镁铁质承载系统中的最大能量是通过氢氧化获得的。此外，热力学模型表明，最大的生物量潜力来自玄武岩中的硫化物氧化和超镁铁质系统中的氢氧化。我们通过测量生物硫化物和氢的去除以及随后在来自玄武岩和超镁铁质火山口的化学性质不同的热液流体中的自养CO2固定来测试这些预测。我们发现，在天然富氢（超镁铁质）和天然贫氢（玄武岩）热液流体中，微生物氢氧化具有很大的潜力。此外，在我们的孵化条件下，基于氢氧化的初级生产被证明是非常有吸引力的，无论使用的是来自超镁铁岩还是玄武岩的热液流体。现场特定的氢和硫化物的可用性似乎并不能确定氢或硫化物氧化是否为测试的热液流体中的自由生活微生物提供初级生产的能量。这表明更复杂的特征（例如，氧气、温度、生物相互作用的组合）可能在确定哪种能源最好用于化学性质不同的热液喷口生境方面发挥作用。
Hydrothermal fluids passing through basaltic rocks along mid‐ocean ridges are known to be enriched in sulfide, while those circulating through ultramafic mantle rocks are typically elevated in hydrogen. Therefore, it has been estimated that the maximum energy in basalt‐hosted systems is available through sulfide oxidation and in ultramafic‐hosted systems through hydrogen oxidation. Furthermore, thermodynamic models suggest that the greatest biomass potential arises from sulfide oxidation in basalt‐hosted and from hydrogen oxidation in ultramafic‐hosted systems. We tested these predictions by measuring biological sulfide and hydrogen removal and subsequent autotrophic CO2 fixation in chemically distinct hydrothermal fluids from basalt‐hosted and ultramafic‐hosted vents. We found a large potential of microbial hydrogen oxidation in naturally hydrogen‐rich (ultramafic‐hosted) but also in naturally hydrogen‐poor (basalt‐hosted) hydrothermal fluids. Moreover, hydrogen oxidation–based primary production proved to be highly attractive under our incubation conditions regardless whether hydrothermal fluids from ultramafic‐hosted or basalt‐hosted sites were used. Site‐specific hydrogen and sulfide availability alone did not appear to determine whether hydrogen or sulfide oxidation provides the energy for primary production by the free‐living microbes in the tested hydrothermal fluids. This suggests that more complex features (e.g., a combination of oxygen, temperature, biological interactions) may play a role for determining which energy source is preferably used in chemically distinct hydrothermal vent biotopes.