Microbial Iron(II) Oxidation in Littoral Freshwater Lake Sediment: The Potential for Competition between Phototrophic vs. Nitrate-Reducing Iron(II)-Oxidizers.
Microbial Iron(II) Oxidation in Littoral Freshwater Lake Sediment: The Potential for Competition between Phototrophic vs. Nitrate-Reducing Iron(II)-Oxidizers.
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DOI：
10.3389/fmicb.2012.00197
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发表时间：
2012
影响因子：
5.2
通讯作者：
Kappler A
中科院分区：
文献类型：
--
作者：
Melton ED;Schmidt C;Kappler A
嗜酸性微生物铁氧化作用的分布主要由氧、光、硝酸盐和亚铁离子的局部梯度决定。在沿岸的淡水湖沉积物的缺氧顶部，硝酸盐还原型和光养型Fe（II）氧化剂竞争同一个e−供体：还原铁。目前还不清楚这些微生物如何在沉积物中共存，以及它们在铁循环中发挥什么作用。我们发现，这两种代谢类型的厌氧Fe（II）氧化微生物存在于同一沉积层直接下面的缺氧-缺氧沉积物界面。光养铁氧化菌的最大可能数为3.4·105个·g−1，自养和兼养硝酸盐还原铁氧化菌的最大可能数分别为1.8·104和4.5·104个·g−1干重沉积物。为了区分两种微生物的Fe（II）氧化过程，并评估其各自的贡献，沉积铁循环，沿岸的湖泊沉积物中培养的微观实验。硝酸盐还原Fe（II）氧化细菌表现出较高的最大Fe（II）氧化速率每细胞，在纯培养物和缩影，比photoferrootrophs。在微观世界中，光致铁营养菌立即开始氧化Fe（II），而硝酸盐还原Fe（II）氧化剂显示出一个显著的滞后期，在此期间，它们可能在开始Fe（II）氧化之前使用有机物作为电子供体。这表明它们在最佳光照条件下会被光养型Fe（II）氧化剂所击败;因为光养型生物在硝酸盐还原型Fe（II）氧化剂开始Fe（II）氧化之前耗尽Fe（II）。因此，两种厌氧Fe（II）氧化剂的共存可能是由于昼夜循环在时间上的生态位空间分离，其中硝酸盐还原Fe（II）氧化剂在黑暗期间氧化Fe（II），而光养生物在白天期间的Fe（II）氧化中起主导作用。此外，Fe（II）氧化微生物的代谢灵活性可能在沉积铁循环的保护中发挥至关重要的作用。
The distribution of neutrophilic microbial iron oxidation is mainly determined by local gradients of oxygen, light, nitrate and ferrous iron. In the anoxic top part of littoral freshwater lake sediment, nitrate-reducing and phototrophic Fe(II)-oxidizers compete for the same e− donor; reduced iron. It is not yet understood how these microbes co-exist in the sediment and what role they play in the Fe cycle. We show that both metabolic types of anaerobic Fe(II)-oxidizing microorganisms are present in the same sediment layer directly beneath the oxic-anoxic sediment interface. The photoferrotrophic most probable number counted 3.4·105 cells·g−1 and the autotrophic and mixotrophic nitrate-reducing Fe(II)-oxidizers totaled 1.8·104 and 4.5·104 cells·g−1 dry weight sediment, respectively. To distinguish between the two microbial Fe(II) oxidation processes and assess their individual contribution to the sedimentary Fe cycle, littoral lake sediment was incubated in microcosm experiments. Nitrate-reducing Fe(II)-oxidizing bacteria exhibited a higher maximum Fe(II) oxidation rate per cell, in both pure cultures and microcosms, than photoferrotrophs. In microcosms, photoferrotrophs instantly started oxidizing Fe(II), whilst nitrate-reducing Fe(II)-oxidizers showed a significant lag-phase during which they probably use organics as e− donor before initiating Fe(II) oxidation. This suggests that they will be outcompeted by phototrophic Fe(II)-oxidizers during optimal light conditions; as phototrophs deplete Fe(II) before nitrate-reducing Fe(II)-oxidizers start Fe(II) oxidation. Thus, the co-existence of the two anaerobic Fe(II)-oxidizers may be possible due to a niche space separation in time by the day-night cycle, where nitrate-reducing Fe(II)-oxidizers oxidize Fe(II) during darkness and phototrophs play a dominant role in Fe(II) oxidation during daylight. Furthermore, metabolic flexibility of Fe(II)-oxidizing microbes may play a paramount role in the conservation of the sedimentary Fe cycle.
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影响因子：
4.4
作者：
Emerson, D;Moyer, C
通讯作者：
Moyer, C
影响因子：
4.2
作者：
Hegler, Florian;Posth, Nicole R.;Kappler, Andreas
通讯作者：
Kappler, Andreas
影响因子：
4.4
作者：
EHRENREICH, A;WIDDEL, F
通讯作者：
WIDDEL, F
影响因子：
4.4
作者：
Jiao, YYQ;Kappler, A;Newman, DK
通讯作者：
Newman, DK
影响因子：
4.4
作者：
Bloethe, Marco;Roden, Eric E.
通讯作者：
Roden, Eric E.