Diversity and Distribution of Thermoacidophiles and Hydrogen Oxidizers at Deep-sea Hydrothermal Vents
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? The first cultured member of the deep-sea endemic archeael lineage, DHVE2, is a thermoacidophile (Reysenbach et al., 2006, Nature 442:444-447), and as part of this cruise we will further our understanding of the molecular physiological ecology and biogeography of this important archaeal lineage at hydrothermal vents. Using a combination of molecular and culturing approaches, we will determine the spatial distribution, relative abundance and co-occurrence patterns of thermoacidophiles with other microorganisms in chimneys from Mid-Atlantic Ridge. Additionally, we will explore the metabolic diversity of thermophiles, including hydrogen oxidizers, nitrate reducers, anaerobic ammonia oxidizers and numerous heterotrophs capable of utilizing such substrates as chitin. We will also use functional gene assays to determine the relative abundance of a suite of metabolisms including methanogensis and sulfate reduction.