title: Microbial species richness and metabolic activities in hypersaline microbial mats: insight into biosignature formation through lithification.
abstract: Microbial mats in the hypersaline lake of Salt Pan, Eleuthera, Bahamas, display a gradient of lithification along a transect from the center to the shore of the lake. These mats exist under similar geochemical conditions, with light quantity and quality as the sole major environmental difference. Therefore, we hypothesized that the microbial community may be driving the differences in lithification and, by extension, mineral biosignature formation. The lithifying and non-lithifying mat communities were compared (via 16S rRNA gene sequencing, 485 and 464 sequences, respectively) over both temporal and spatial scales. Seven bacterial groups dominated in all the microbial mat libraries: bacteriodetes, alphaproteobacteria, deltaproetobacteria, chloroflexi, spirochaetes, cyanobacteria, and planctomycetes. The mat communities were all significantly different over space, time, and lithification state. Species richness is significantly higher in the non-lithifying mats, potentially due to differences in mat structure and activity. This increased richness may impact lithification and, hence, biosignature production.
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, Connecticut, USA.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Baumgartner
authors.forename: Christophe
authors.initials: C
authors.lastname: Dupraz
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Buckley
authors.forename: John R
authors.initials: JR
authors.lastname: Spear
authors.forename: Norman R
authors.initials: NR
authors.lastname: Pace
authors.forename: Pieter T
authors.initials: PT
authors.lastname: Visscher
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D001444:Bahamas; D001483:Base Sequence; D044822:Biodiversity; D004777:Environment; D015723:Gene Library; D005843:Geography; D019015:Geologic Sediments / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008027:Light; D010101:Oxygen Consumption / Q000528:radiation effects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D017422:Sequence Analysis, DNA; D013696:Temperature; D013997:Time Factors; D014871:Water Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S