Diversity and distribution of thermoacidophiles at deep-sea hydrothermal vents

微生物活动对热液喷口生态系统的地质、地球化学和生态的重要性和影响现已得到公认。直到最近，一个一直令人费解的方面是--为什么在通风液pH值较低的情况下，没有从这些生态系统中分离出嗜酸菌？鉴于最近的发现，深海特有的始祖鱼谱系中第一个被培养的成员DHVE2是一种嗜热性酸菌，在pH 4.5时生长最好，不能在pH 6以上生长，因此该项目的研究人员准备将这种生物作为模式生物来探索深海喷口的嗜热性酸菌的生态。此外，这是在许多分子分类研究中发现的最丰富的古菌谱系，占古菌群落的15%，目前文特尔研究所正在对其基因组进行测序。因此，这项研究将进一步加深我们对热液喷口这一重要古生物谱系的分子生理生态和生物地理学的了解。该项目的长期目标是深入了解嗜热酸菌在深海热液喷口生态系统中所起的作用。具体目标包括了解东部刘扩散中心、瓜伊马斯盆地和大西洋中脊喷口遗址烟囱中嗜热古细菌的空间分布、相对丰度和共生模式，并检查这些地点的喷口化学物质，因为它们可能对嗜热细菌的发生产生重大影响，并影响与其他喷口微生物对重叠生态位的竞争。该项目的研究人员预测，在中等pH(pH 3-5)的深海喷口地点，嗜热酸菌将更加丰富，而在极端喷口流体pH(pH 3，5)的地点，它们将不那么丰富。为了完成这项工作，研究人员将从上面提到的三个不同的深海热液喷口系统收集烟囱样本。将对在这些地点收集的样本进行各种培养和分子技术，以考察喷口地点之间嗜热性酸菌的多样性，它们与其他喷口细菌竞争的能力，以及它们的代谢活性。此外，来自深海喷口的新的嗜热性酸菌将被分离和鉴定。嗜热酸菌的独特生物学正被用于生物浸出/生物采矿应用，从深海喷口发现新的嗜热酸菌有可能为这些生物的生物修复和生物技术应用提供工具。调查人员还参与了少数民族研究生和高中理科教师的培训。

The importance and impact that microbial activity has on the geology, geochemistry and ecology of hydrothermal vent ecosystems is now well-recognized. One aspect that has until recently been a puzzle, is --why with the low vent fluid pH had no acidophiles been isolated from these ecosystems? Given the recent discovery that the first cultured member of the deep-sea endemic archeael lineage, DHVE2, is a thermoacidophile, growing best at pH 4.5 and unable to grow above pH 6, the investigators in this project are poised to use this organism as a model organism to explore the ecology of thermoacidophiles at deep-sea vents. Furthermore, this is the most abundant archaeal lineage detected in many molecular taxonomy studies, representing up to 15% of the archaeal community, and its genome is currently being sequenced by the Venter Institute. Therefore, the proposed study will further our understanding of the molecular physiological ecology and biogeography of this important archaeal lineage at hydrothermal vents. The long-term objective of this project is to provide insights into the role that thermoacidophiles play in deep-sea hydrothermal vent ecosystems. Specific objectives include understanding the spatial distribution, relative abundance and co-occurrence patterns of thermoacidophilic archaea in chimneys from the Eastern Lau Spreading Center, Guaymas Basin and Mid-Atlanic Ridge vent sites, and to examine the vent chemistries at these sites as they could have dramatic effects on the occurrence of thermoacidophiles and affect the competition for overlapping niches with other vent microbes. The investigators in this project are predicting that thermoacidophiles will be more abundant at deep-sea vent sites of intermediate pH (pH 3-5), whereas they will be less abundant in sites with extreme vent fluid pH (pH 3, 5). To accomplish this work the investigators will collect chimney samples from the three contrasting deep-sea hydrothermal vent systems named above. A variety of cultivation and molecular techniques will be conducted on samples collected at these locations to look at the diversity of thermoacidophiles between vent sites, their ability to compete with other vent bacteria, and their metabolic activity. Additionally, new thermoacidophiles from deep-sea vents will be isolated and characterized. The unique biology of thermoacidophiles is being used in bioleaching/biomining applications and the discovery of new thermoacidophiles from deep-sea vents has the potential to provide tools for bioremediation and biotechnological applications by these organisms. The investigators are also involved in the training of minority graduate students and high school science teachers.