Assembly and Succession of Iron Oxide Microbial Mat Communities in Acidic Geothermal Springs.
Assembly and Succession of Iron Oxide Microbial Mat Communities in Acidic Geothermal Springs.
复制标题
DOI：
10.3389/fmicb.2016.00025
复制
发表时间：
2016
影响因子：
5.2
通讯作者：
Inskeep WP
中科院分区：
文献类型：
--
作者：
Beam JP;Bernstein HC;Jay ZJ;Kozubal MA;Jennings Rd;Tringe SG;Inskeep WP
生物矿化氧化铁微生物垫是地球上普遍存在的特征，在美国黄石国家公园（YNP， WY， USA）的温泉中很常见，是微生物与物理化学过程直接相互作用的结果。本研究的总体目标是确定不同群落成员对酸性高温铁(III)-氧化物垫生态系统的组装和演替的贡献。采用无菌玻璃显微镜载玻片，在YNP两个酸性地热温泉（pH = 3-3.5，温度= 68-75℃）的流出通道中孵育70 d，监测了Fe(III)-氧化物的时空变化和相关群落成员的丰度。在演替早期（4 ~ 40天），发现的种类最多的是hydroobaculum spp.，它们具有氧化亚砷酸盐、硫化物和氢耦合氧还原的作用。在4天内检测到黄颡鱼的铁氧化群体，并在14-30天内达到稳态水平，对应于可见的Fe（III）氧化物增加。异养古细菌在30天左右定植，70天后在成熟的铁(III)-氧化物垫（1-2 cm厚）中形成优势功能群落。Fe(III)-氧化物的一阶速率常数范围为0.046至0.05天−1，原位微电极测量表明，Fe（II）的氧化受到O2向Fe(III)-氧化物垫中的扩散的限制。微平台的形成也表明O2是控制微生物生长和随后垫形态的主要变量。铁(III)-氧化物垫群落的组装和演替遵循一个可重复的模式，即由石自养生物定殖，以及随后各种有机异养生物的生长。现存生物矿化铁（III）氧化垫独特的地球化学特征和微观形态也有助于理解其他铁（II）氧化体系。
Biomineralized ferric oxide microbial mats are ubiquitous features on Earth, are common in hot springs of Yellowstone National Park (YNP, WY, USA), and form due to direct interaction between microbial and physicochemical processes. The overall goal of this study was to determine the contribution of different community members to the assembly and succession of acidic high-temperature Fe(III)-oxide mat ecosystems. Spatial and temporal changes in Fe(III)-oxide accretion and the abundance of relevant community members were monitored over 70 days using sterile glass microscope slides incubated in the outflow channels of two acidic geothermal springs (pH = 3–3.5; temperature = 68–75°C) in YNP. Hydrogenobaculum spp. were the most abundant taxon identified during early successional stages (4–40 days), and have been shown to oxidize arsenite, sulfide, and hydrogen coupled to oxygen reduction. Iron-oxidizing populations of Metallosphaera yellowstonensis were detected within 4 days, and reached steady-state levels within 14–30 days, corresponding to visible Fe(III)-oxide accretion. Heterotrophic archaea colonized near 30 days, and emerged as the dominant functional guild after 70 days and in mature Fe(III)-oxide mats (1–2 cm thick). First-order rate constants of Fe(III)-oxide accretion ranged from 0.046 to 0.05 day−1, and in situ microelectrode measurements showed that the oxidation of Fe(II) is limited by the diffusion of O2 into the Fe(III)-oxide mat. The formation of microterracettes also implicated O2 as a major variable controlling microbial growth and subsequent mat morphology. The assembly and succession of Fe(III)-oxide mat communities follows a repeatable pattern of colonization by lithoautotrophic organisms, and the subsequent growth of diverse organoheterotrophs. The unique geochemical signatures and micromorphology of extant biomineralized Fe(III)-oxide mats are also useful for understanding other Fe(II)-oxidizing systems.