@article {ISI:000373276200001,
	title = {{Temperature and Redox Effect on Mineral Colonization in Juan de Fuca Ridge Flank Subsurface Crustal Fluids}},
	journal = {FRONTIERS IN MICROBIOLOGY},
	volume = {7},
	year = {2016},
	month = {mar},
	type = {Article},
	abstract = {To examine microbe-mineral interactions in subsurface oceanic crust, we evaluated microbial colonization on crustal minerals that were incubated in borehole fluids for 1 year at the seafloor wellhead of a crustal borehole observatory (IODP Hole U1301A, Juan de Fuca Ridge flank) as compared to an experiment that was not exposed to subsurface crustal fluids (at nearby IODP Hole U1301B). In comparison to previous studies at these same sites, this approach allowed assessment of the effects of temperature, fluid chemistry, and/or mineralogy on colonization patterns of different mineral substrates, and an opportunity to verify the approach of deploying colonization experiments at an observatory wellhead at the seafloor instead of within the borehole. The Hole U1301B deployment did not have biofilm growth, based on microscopy and DNA extraction, thereby confirming the integrity of the colonization design against bottom seawater intrusion. In contrast, the Hole U1301A deployment supported biofilms dominated by Epsilonproteobacteria (43.5{\%} of 370 16S rRNA gene clone sequences) and Gammaproteobacteria (29.3{\%}). Sequence analysis revealed overlap in microbial communities between different minerals incubated at the Hole U1301A wellhead, indicating that mineralogy did not separate biofilm structure within the 1-year colonization experiment. Differences in the Hole U1301A wellhead biofilm community composition relative to previous studies from within the borehole using similar mineral substrates suggest that temperature and the diffusion of dissolved oxygen through plastic components influenced the mineral colonization experiments positioned at the wellhead. This highlights the capacity of low abundance crustal fluid taxa to rapidly establish communities on diverse mineral substrates under changing environmental conditions such as from temperature and oxygen.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {1664-302X},
	doi = {10.3339/fmicb.2016.00396},
	author = {Baquiran, Jean-Paul M and Ramirez, Gustavo A and Haddad, Amanda G and Toner, Brandy M and Hulme, Samuel and Wheat, Charles G and Edwards, Katrina J and Orcutt, Beth N}
}
@article {ISI:000367001600001,
	title = {{Microbial Communities on Seafloor Basalts at Dorado Outcrop Reflect Level of Alteration and Highlight Global Lithic Clades}},
	journal = {FRONTIERS IN MICROBIOLOGY},
	volume = {6},
	year = {2015},
	month = {dec},
	type = {Article},
	abstract = {Areas of exposed basalt along mid-ocean ridges and at seafloor outcrops serve as conduits of fluid flux into and out of a subsurface ocean, and microbe-mineral interactions can influence alteration reactions at the rock-water interface. Located on the eastern flank of the East Pacific Rise, Dorado Outcrop is a site of low temperature ({\textless} 20 degrees C) hydrothermal venting and represents a new end-member in the current survey of seafloor basalt biomes. Consistent with prior studies, a survey of 16S rRNA gene sequence diversity using universal primers targeting the V4 hypervariable region revealed much greater richness and diversity on the seafloor rocks than in surrounding seawater. Overall, Gamma-, Alpha-, and Deltaproteobacteria, and Thaumarchaeota dominated the sequenced communities, together making up over half of the observed diversity, though bacterial sequences were more abundant than archaeal in all samples. The most abundant bacterial reads were closely related to the obligate chemolithoautotrophic, sulfur-oxidizing Thioprofundum lifl-lotrophicum, suggesting carbon and sulfur cycling as dominant metabolic pathways in this system. Representatives of Thaumarchaeota were detected in relatively high abundance on the basalts in comparison to bottom water, possibly indicating ammonia oxidation. In comparison to other sequence datasets from globally distributed seafloor basalts, this study reveals many overlapping and cosmopolitan phylogenetic groups and also suggests that substrate age correlates with community structure.},
	keywords = {AUV Sentry (Autonomous Underwater Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {1664-302X},
	doi = {10.3389/fmicb.2015.01470},
	author = {Lee, Michael D and Walworth, Nathan G and Sylvan, Jason B and Edwards, Katrina J and Orcutt, Beth N}
}
@article {ISI:000331005900001,
	title = {{Low temperature geomicrobiology follows host rock composition along a geochemical gradient in Lau Basin}},
	journal = {FRONTIERS IN MICROBIOLOGY},
	volume = {4},
	year = {2013},
	month = {mar},
	type = {Article},
	abstract = {The East Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) comprise a ridge segment in the southwest Pacific Ocean where rapid transitions in the underlying mantle chemistry manifest themselves as gradients in seafloor rock geochemistry. We studied the geology and microbial diversity of three silicate rock samples and three inactive sulfide chimney samples collected, from north to south, at the vent fields Kilo Moana, ABE, Tui Malila, and Mariner. This is the first study of microbial populations on basaltic andesite, which was sampled at Mariner vent field. Silicate rock geochemistry exhibits clear latitudinal trends that are mirrored by changes in bacterial community composition. alpha-proteobacteria, epsilon-proteobacteria, and Bacteroidetes are most common on a silicate collected from Kilo Moana and their proportions decrease linearly on silicates collected further south. Conversely, a silicate from Mariner vent field hosts high proportions of a unique lineage of Chloroflexi unrelated ({\textless}90{\%} sequence similarity) to previously recovered environmental clones or isolates, which decrease at ABE and are absent at Kilo Moana. The exteriors of inactive sulfide structures are dominated by lineages of sulfur oxidizing alpha-proteobacteria, gamma-proteobacteria, and epsilon-proteobacteria, while the interior of one chimney is dominated by putative sulfur-reducing delta-proteobacteria. A comparison of bacterial communities on inactive sulfides from this and previous studies reveals the presence of a clade of uncultured Bacteroidetes exclusive to sulfidic environments, and a high degree of heterogeneity in bacterial community composition from one sulfide structure to another. In light of the heterogeneous nature of bacterial communities observed here and in previous studies of both active and inactive hydrothermal sulfide structures, the presence of numerous niches may be detected on these structures in the future by finer scale sampling and analysis.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {1664-302X},
	doi = {10.3389/fmicb.2013.00061},
	author = {Sylvan, Jason B and Sia, Tiffany Y and Haddad, Amanda G and Briscoe, Lindsey J and Toner, Brandy M and Girguis, Peter R and Edwards, Katrina J}
}
