Microbialites: Organosedimentary Deposits of Benthic Microbial Communities

Burne, Robert V.; Moore, Linda S.

doi:10.2307/3514674

Cited by 841 publications

(474 citation statements)

References 48 publications

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“…Microbialites are organosedimentary deposits that have built up as a result of benthic microbial community growth in concert with trapping and binding of detrital sediment and/or forming the locus of mineral precipitation [12]. Microbialites can be separated according their internal structure, into stromatolites (laminated structures), thrombolites (clotted structures), cryptic microbialites (patchy texture), oncolites (concentric laminations), and spherulitic microbialites (spherular aggregates) [30,45].…”

Section: Introductionmentioning

confidence: 99%

Irradiance Regulation of Photosynthesis and Respiration in Modern Marine Microbialites Built by Benthic Cyanobacteria in a Tropical Lagoon (New Caledonia)

2005

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Microbialites are organosedimentary deposits that have built up as a result of the growth and binding of detrital sediment by a benthic microbial community. This study focuses on microbialites built by monospecific populations of cyanobacteria in the south-west lagoon of New Caledonia, where they have been observed down to 20-25 m depth. The aim was to study their photosynthetic and respiratory responses to various light intensities. The Phormidium sp. TK1 microbialite was collected at 19 m depth and the P. crosbyanum (Tilden) microbialite was collected at 0.5 and 13 m depth. Phormidium sp. TK1 showed all the characteristic features of a low-light adapted species. The initial slope of the Photosynthesis versus Irradiance curve for this microbialite was close to the maximum quantum yield indicating an efficient light absorption and utilization at low light. The photosynthesis maximum was located 0.2-0.4 mm below the surface and did not shift with changing light intensity. Respiration rates were low and not enhanced by light; photoinhibition was observed at higher light intensities. In Phormidium crosbyanum (Tilden) microbialites, the photosynthesis maximum shifted downward to lower depths with increasing light, probably as a result of phototactic migration of cyanobacterial filaments, and light-enhanced respiration was observed at light intensities above light saturation. The photosynthetic parameters measured in P. crosbyanum indicate that P. crosbyanum is capable of photo-acclimation at high light intensities. The gross productivity of the different microbialites was comparable to values measured in cyanobacterial stromatolites observed in other shallow environments. However, the microbialites studied here were characterized by a lower respiration / production ratio which indicates a higher growth efficiency.

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Section: Introductionmentioning

confidence: 99%

Irradiance Regulation of Photosynthesis and Respiration in Modern Marine Microbialites Built by Benthic Cyanobacteria in a Tropical Lagoon (New Caledonia)

2005

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“…Burne & Moore, 1987;Chafetz & Buczynski, 1992). Both laminite types are characterized by couplets of darker laminae with rough lamina tops that alternate with lighter laminae with smooth lamina tops.…”

Section: C Irregular and Mottled Laminitesmentioning

confidence: 99%

Geomorphic evolution of a storm-dominated carbonate ramp (c. 549 Ma), Nama Group, Namibia

DiBenedetto

Grotzinger

2005

Geol. Mag.

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-The well-exposed Hoogland Member (c. 549 Ma) of the northern Nama Group (Kuibis Subgroup), Namibia, represents a storm-dominated carbonate ramp developed in a foreland basin of terminal Proterozoic age. The ramp displays facies gradients involving updip grainstones which pass downdip into broad, spatially extensive tracts of microbial laminites and finely laminated mudstones deposited above and below storm wave base. Trough cross-bedded, coarse grainstones are shown to transit downdip into finer-grained calcarenites, irregular microbial laminites and mottled laminites. Siliciclastic siltstones and shales were deposited further downdip. Platform growth was terminated through smothering by orogen-derived siliciclastic deposits. Ramp morphology was controlled by several different processes which acted across many orders of magnitude (millimetres to kilometres), including in situ growth of mats and reefs, scouring by wave-produced currents, and transport and infilling of coarse-grained carbonates and fine-grained carbonates and clastics. At the smallest scale, 'roughening' of the sea-floor through heterogeneous trapping and binding by microbial mats was balanced by smoothing of the sea-floor through accumulation of loose sediment to fill the topographic lows within the upward-propagating mat. At the next scale up, parasequence development involved roughening of the sea-floor through shoal growth and grainstone progradation, balanced by sea-floor smoothing through shale infilling of resulting downdip accommodation, as well as the metre-scale topographic depressions within the mosaic of shoal-water facies. At even larger (sequence/platform) scales, roughening of the sea-floor occurred through aggradation and progradation of thick carbonates, balanced by infilling of the foreland basin with orogen-derived siliciclastic sediments. At all scales a net balance was achieved between sea-floor roughening and sea-floor smoothing to maintain a more or less constant ramp profile.

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“…Microbialites are organo-sedimentary structures that form in modern marine and nonmarine environments through the accretion of sediment by benthic microbial communities (e.g., Burne and Moore 1987). Based on their internal fabric, microbialites are subdivided into two distinct groups as per Shapiro (2000): (1) stromatolites, which show internally laminated mesostructures (as originally defined by Kalkowsky 1908), and (2) thrombolites, distinguished by their nonlaminated and clotted mesostructrue (Aitken 1967).…”

Section: Introductionmentioning

confidence: 99%

Textural and Geochemical Features of Freshwater Microbialites From Laguna Bacalar, Quintana Roo, Mexico

Castro-Contreras¹,

Gingras²,

Peçoits³

et al. 2014

PALAIOS

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Microbialites provide some of the oldest direct evidence of life on Earth. They reached their peak during the Proterozoic and declined afterward. Their decline has been attributed to grazing and/or burrowing by metazoans, to changes in ocean chemistry, or to competition with other calcifying organisms.The freshwater microbialites at Laguna Bacalar (Mexico) provide an opportunity to better understand microbialite growth in terms of interaction between grazing organisms versus calcium carbonate precipitation. The Laguna Bacalar microbialites are described in terms of their distinct mesostructures. Stromatolites display internal lamination, attributed to the precipitation of calcite and the upward migration of cyanobacteria during periods of low sedimentation. Thrombolitic stromatolites show internal lamination in addition to internal clotting. The clotting is seen as a result of binding and/or trapping of micritic peloids by cyanobacteria and attributed to periods of high sedimentation. The carbonates in both microbialites had similar C-and Ostable-isotopic signatures, both enriched in 13 C relative to bivalves, suggesting photosynthetic CO 2 uptake was the trigger for carbonate precipitation. This implies that the rate of microbialite growth is largely a function of ambient carbonate saturation state, while the texture is especially dependent on accretion rates and sediment deposition on their surface. Importantly, the coexistence with grazing animals suggests no significant inhibition on microbialite growth, thereby calling into question the decline of microbialite as a result of metazoan evolution. Varying sedimentation rates are likely important in controlling the distribution of thrombolite-stromatolite packages in the geological record, given the importance of this factor at Bacalar.

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Microbialites: Organosedimentary Deposits of Benthic Microbial Communities

Cited by 841 publications

References 48 publications

Irradiance Regulation of Photosynthesis and Respiration in Modern Marine Microbialites Built by Benthic Cyanobacteria in a Tropical Lagoon (New Caledonia)

Irradiance Regulation of Photosynthesis and Respiration in Modern Marine Microbialites Built by Benthic Cyanobacteria in a Tropical Lagoon (New Caledonia)

Geomorphic evolution of a storm-dominated carbonate ramp (c. 549 Ma), Nama Group, Namibia

Textural and Geochemical Features of Freshwater Microbialites From Laguna Bacalar, Quintana Roo, Mexico

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