title: Low temperature geomicrobiology follows host rock composition along a geochemical gradient in lau basin.
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. α-proteobacteria, ε-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 (<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 α-proteobacteria, γ-proteobacteria, and ε-proteobacteria, while the interior of one chimney is dominated by putative sulfur-reducing δ-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.
authors.affiliation: Department of Biological Sciences, University of Southern California Los Angeles, CA, USA.
authors.forename: Jason B
authors.initials: JB
authors.lastname: Sylvan
authors.forename: Tiffany Y
authors.initials: TY
authors.lastname: Sia
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Haddad
authors.forename: Lindsey J
authors.initials: LJ
authors.lastname: Briscoe
authors.forename: Brandy M
authors.initials: BM
authors.lastname: Toner
authors.forename: Peter R
authors.initials: PR
authors.lastname: Girguis
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Edwards
keywords: bacteroidetes; basalt; geomicrobiology; hydrothermal; inactive sulfides
references.citation: Appl Environ Microbiol. 2004 Feb;70(2):1190-8
references.pmid: 14766605
references.citation: Science. 2009 Oct 23;326(5952):578-82
references.pmid: 19900896
references.citation: Environ Microbiol. 2010 Jul;12(7):1889-98
references.pmid: 20236171
references.citation: FEMS Microbiol Lett. 2008 May;282(2):182-7
references.pmid: 18355287
references.citation: mBio. 2012 Jan 24;3(1):e00279-11
references.pmid: 22275502
references.citation: Science. 2005 Sep 30;309(5744):2179
references.pmid: 16195451
references.citation: Int J Syst Evol Microbiol. 2005 Mar;55(Pt 2):925-933
references.pmid: 15774687
references.citation: Environ Microbiol. 2006 May;8(5):909-20
references.pmid: 16623747
references.citation: FEMS Microbiol Ecol. 2004 Nov 1;50(3):213-30
references.pmid: 19712362
references.citation: Proc Natl Acad Sci U S A. 2010 Aug 10;107(32):14020-5
references.pmid: 20660317
references.citation: Appl Environ Microbiol. 2004 May;70(5):2741-7
references.pmid: 15128527
references.citation: Nucleic Acids Res. 2006 Jul 1;34(Web Server issue):W394-9
references.pmid: 16845035
references.citation: J Mol Biol. 1990 Oct 5;215(3):403-10
references.pmid: 2231712
references.citation: ISME J. 2009 Feb;3(2):231-42
references.pmid: 18843298
references.citation: Appl Environ Microbiol. 2001 Nov;67(11):5273-84
references.pmid: 11679356
references.citation: Nature. 2008 May 29;453(7195):653-6
references.pmid: 18509444
references.citation: Nat Rev Microbiol. 2006 Jun;4(6):458-68
references.pmid: 16652138
references.citation: Appl Environ Microbiol. 2009 Dec;75(23):7537-41
references.pmid: 19801464
references.citation: Environ Microbiol. 2010 May;12(5):1334-47
references.pmid: 20192971
references.citation: Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5685-9
references.pmid: 1608980
references.citation: Nucleic Acids Res. 2004 Feb 25;32(4):1363-71
references.pmid: 14985472
references.citation: Environ Microbiol. 2009 Jan;11(1):86-98
references.pmid: 18783382
references.citation: Microb Ecol. 2004 Feb;47(2):186-96
references.pmid: 14749907
references.citation: Appl Environ Microbiol. 2006 Jul;72(7):5069-72
references.pmid: 16820507
references.citation: Appl Environ Microbiol. 2003 Jun;69(6):3580-92
references.pmid: 12788766
references.citation: Environ Microbiol. 2007 Feb;9(2):546-54
references.pmid: 17222152
references.citation: Geobiology. 2012 Mar;10(2):178-92
references.pmid: 22221398
references.citation: ISME J. 2010 Jun;4(6):784-98
references.pmid: 20072162
references.citation: Extremophiles. 2008 May;12(3):431-9
references.pmid: 18317684
references.citation: Appl Environ Microbiol. 2010 May;76(9):2968-79
references.pmid: 20228114
references.citation: Geobiology. 2012 Jul;10(4):333-46
references.pmid: 22443386
references.citation: Mol Biol Evol. 2011 Oct;28(10):2731-9
references.pmid: 21546353
references.citation: Appl Environ Microbiol. 2000 Nov;66(11):5066-72
references.pmid: 11055964
references.citation: Int J Syst Evol Microbiol. 2006 Aug;56(Pt 8):1725-1733
references.pmid: 16901999
references.citation: Nature. 2011 Jan 13;469(7329):198-202
references.pmid: 21228874