title: Changing microspatial patterns of sulfate-reducing microorganisms (SRM) during cycling of marine stromatolite mats.
abstract: Microspatial arrangements of sulfate-reducing microorganisms (SRM) in surface microbial mats (~1.5 mm) forming open marine stromatolites were investigated. Previous research revealed three different mat types associated with these stromatolites, each with a unique petrographic signature. Here we focused on comparing "non-lithifying" (Type-1) and "lithifying" (Type-2) mats. Our results revealed three major trends: (1) Molecular typing using the dsrA probe revealed a shift in the SRM community composition between Type-1 and Type-2 mats. Fluorescence in-situ hybridization (FISH) coupled to confocal scanning-laser microscopy (CSLM)-based image analyses, and 35SO4(2-)-silver foil patterns showed that SRM were present in surfaces of both mat types, but in significantly (p < 0.05) higher abundances in Type-2 mats. Over 85% of SRM cells in the top 0.5 mm of Type-2 mats were contained in a dense 130 µm thick horizontal layer comprised of clusters of varying sizes; (2) Microspatial mapping revealed that locations of SRM and CaCO3 precipitation were significantly correlated (p < 0.05); (3) Extracts from Type-2 mats contained acylhomoserine-lactones (C4- ,C6- ,oxo-C6,C7- ,C8- ,C10- ,C12- , C14-AHLs) involved in cell-cell communication. Similar AHLs were produced by SRM mat-isolates. These trends suggest that development of a microspatially-organized SRM community is closely-associated with the hallmark transition of stromatolite surface mats from a non-lithifying to a lithifying state.
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. alexandru_petrisor@yahoo.com.
authors.forename: Alexandru I
authors.initials: AI
authors.lastname: Petrisor
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. Sandra.szyjka@stud.uni-due.de.
authors.forename: Sandra
authors.initials: S
authors.lastname: Szyjka
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. tkawaguchi@allenuniversity.edu.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. pieter.visscher@uconn.edu.
authors.forename: Pieter T
authors.initials: PT
authors.lastname: Visscher
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. rsnorman@mailbox.sc.edu.
authors.forename: Robert Sean
authors.initials: RS
authors.lastname: Norman
authors.affiliation: Department of Urban and Landscape Planning, School of Urban Planning, "Ion Mincu" University of Architecture and Urban Planning, str. Academiei nr. 18-20, sector 1, Bucharest 010014, Romania. awdecho@mailbox.sc.edu.
authors.forename: Alan W
authors.initials: AW
authors.lastname: Decho
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002364:Caseins / Q000737:chemistry; D016000:Cluster Analysis; D040362:Geographic Information Systems; D019015:Geologic Sediments / Q000382:microbiology; D010802:Phylogeny; D058727:RNA, Small Untranslated / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry / Q000378:metabolism*; D050864:Sulfite Reductase (NADPH) / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002364:Caseins; D058727:RNA, Small Untranslated; D013431:Sulfates; C484216:calcium caseinate; D050864:Sulfite Reductase (NADPH)