Microbial Mats in Australian Coastal Environments

Skyring, G. W.; Bauld, John

doi:10.1007/978-1-4684-7612-5_12

Cited by 25 publications

(13 citation statements)

References 78 publications

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“…Role of the sulfur cycle Alteration of the SI in mats is clearly a combined community effort, however, evidence is compelling that alkalinity produced by SRB has a prominent role [24,25,27,54]. The crust in both Highborne Cay stromatolites and hypersaline Salt Pan mats coincides with the location of maximum sulfate reduction [27,52] The above exemplifies that the impact of metabolic reactions is complicated, but also demonstrates that decoupling of the different metabolic processes in time and space controlled by physical (e.g.…”

Section: Microbial Metabolism and Saturation Indexmentioning

confidence: 88%

“…Modern stromatolites exist in freshwater systems [47], hypersaline and open marine environments in the Bahamas [51,53] and Shark Bay, Australia [54]. Based on microscopic observation, models of Shark Bay stromatolite formation were proposed [55] and, in separate studies, some microbial activities were reported [54]. Recently, the open marine stromatolites on Highborne Cay (Bahamas) were targeted in a geomicrobial investigation.…”

Section: Lithifying Versus Non-lithifying Matsmentioning

confidence: 99%

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Microbial lithification in marine stromatolites and hypersaline mats

Dupraz

Visscher

2005

Trends in Microbiology

658

634

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Section: Microbial Metabolism and Saturation Indexmentioning

confidence: 88%

Section: Lithifying Versus Non-lithifying Matsmentioning

confidence: 99%

Microbial lithification in marine stromatolites and hypersaline mats

Dupraz

Visscher

2005

Trends in Microbiology

658

634

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“…Inthese ecosystems, cyanobacterial organic carbon substrates may provide the electron-donating substrates for SRB (Jørgensen & Cohen, 1977;Skyring & Bauld, 1990;Fr€ und & Cohen, 1992). Microbial reduction of sulphate is accompanied by carbonate precipitation and replacement in many modern environments (e.g.…”

Section: Microbial Mediation Of Saline Watersmentioning

confidence: 99%

The role of bacterial sulphate reduction in carbonate replacement of vanished evaporites: examples from the Holocene, Jurassic and Neoarchaean

Wright¹,

Kirkham²

2010

Quaternary Carbonate and Evaporite Sedimentary Facies and Their Ancient Analogues

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Vanished evaporites are well documented in the geological record, but many may go unrecognized because of a lack of obvious field or petrographic evidence, particularly in carbonates deposited in restricted settings where bacterial sulphate reduction (BSR) was active. An early stage in evaporite replacement by carbonates may be observed in modern salterns in Eilat, where gypsum crusts are colonized by stratified, endoevaporitic, microbial communities including sulphate-reducing bacteria (SRB). Here, BSR can be associated with gypsum dissolution and replacive carbonate formation. Rapid consumption of aqueous sulphate by SRB is illustrated in the ephemeral Coorong lakes of South Australia, where extremely high concentrations are completely removed by intense BSR during evaporation, so that no solid sulphate precipitates. Here, carbonates form as the consequence of mediation of ambient waters by BSR, with sedimentary pyrite providing the only indication of the former presence of dissolved sulphate in the lake waters.Pyrite patches in the patterned dolomite facies of the largely evaporitic Jurassic Arab Formation have been interpreted as 'birds eyes' or fenestrae, but show no signs of visible porosity. A hostile environment mitigates against their interpretation as burrows, although some form of root pseudomorph is not ruled out. However, it is possible that the pyrite is related to BSR operating in a hypersaline, microbially-dominated environment in which solid sulphate removal and sulphide formation is followed by dolomite formation.Field, petrographic, and stable-isotopic evidence from bedded strata and thin sections of the Neoarchaean Gamohaan and Kogelbeen carbonate formations of South Africa argue for the former existence of evaporites, and suggest deposition in mainly shallow subtidal and marine sabkha environments. On the macroscale, cross-stratified grainstones showing multiple directions of sediment transport, together with abundant microbialites and rare, well-preserved cyanobacterial fossils, indicate shallow-water deposition and microbial growth in the photic zone. Large tepee-like fold structures, intrastratal karst, pseudomorphs after evaporites, replacive calcite after selenite, solution collapse breccias, autobrecciation, corrosion surfaces, nucleation cones, irregular bedding contacts and flowage structures are all indicative of evaporites, their dissolution and their replacement by carbonate.Evaporite replacement in the Neoarchaean carbonates was largely fabric destructive, leaving few obvious clues at the microscale to the former presence of vanished evaporites. Nonetheless, diagenetic recrystallization, deformation, disruption, and crosscutting relationships point to their previous existence, and the occurrence of lengthslow chalcedony in silicified stromatolite heads may suggest the former presence of sulphates. Fold shapes indicative of enterolithic gypsum, picked out by trails of degraded organic matter and dolomitized clusters of folded filaments preserved within replacive calcite, are eviden...

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“…The majority of studies of Hamelin Pool to date focused on the stromatolites, particularly the morphology of the geological structures formed (Logan, 1961; Logan et al ., 1964; Logan et al ., 1974; Reid et al ., 2003), and the influence of environmental factors on their formation such as wind, tidal action and sunlight (Playford, 1980; Awramik & Vanyo, 1986). Earlier investigations of the mats have been limited to microscopy of the dominant cyanobacterial groups (Logan et al ., 1974) and investigation of total community photosynthesis or sulphate reduction rates (Bauld et al ., 1979; Moriarty, 1983; Bauld, 1984; Skyring & Bauld, 1990). Only recently has the microbial diversity of the stromatolites been documented using molecular techniques (Burns et al ., 2004; Papineau et al ., 2005), whereas the bacterial populations of the mats, and their relationship to the lithified communities in such close proximity, are still largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Bacterial, archaeal and eukaryotic diversity of smooth and pustular microbial mat communities in the hypersaline lagoon of Shark Bay

et al. 2009

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The bacterial, archaeal and eukaryotic populations of nonlithifying mats with pustular and smooth morphology from Hamelin Pool, Shark Bay were characterised using small subunit rRNA gene analysis and microbial isolation. A highly diverse bacterial population was detected for each mat, with 16S rDNA clones related to Actinobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Gemmatimonas, Planctomycetes, Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Verrucomicrobia and candidate division TM6 present in each mat. Spirochaetes were detected in the smooth mat only, whereas candidate division OP11 was only detected in the pustular mat. Targeting populations with specific primers revealed additional cyanobacterial diversity. The archaeal population of the pustular mat was comprised purely of Halobacteriales, whereas the smooth mat contained 16S rDNA clones from the Halobacteriales, two groups of Euryarchaea with no close characterised matches, and the Thaumarchaea. Nematodes and fungi were present in each mat type, with diatom 18S rDNA clones only obtained from the smooth mat, and tardigrade and microalgae clones only retrieved from the pustular mat. Cultured isolates belonged to the Firmicutes, Gammaproteobacteria, Alphaproteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, and Halobacteriales. The mat populations were significantly more diverse than those previously reported for Hamelin Pool stromatolites, suggesting specific microbial populations may be associated with the nonlithifying and lithifying microbial communities of Hamelin Pool.

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Microbial Mats in Australian Coastal Environments

Cited by 25 publications

References 78 publications

Microbial lithification in marine stromatolites and hypersaline mats

Microbial lithification in marine stromatolites and hypersaline mats

The role of bacterial sulphate reduction in carbonate replacement of vanished evaporites: examples from the Holocene, Jurassic and Neoarchaean

Bacterial, archaeal and eukaryotic diversity of smooth and pustular microbial mat communities in the hypersaline lagoon of Shark Bay

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