Alternative origins for nannobacteria-like objects in calcite

Kirkland, Brenda L.; Lynch, F. Leo; Rahnis, Michael; Folk, Robert L.; Molineux, Ian J.; McLean, Robert

doi:10.1130/0091-7613(1999)027<0347:aofnlo>2.3.co;2

Cited by 105 publications

(61 citation statements)

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“…After 3 days all the nanobacteria-like objects observed at the first stages by Kirkland et al were absent in all the experiments, and calcite was present as large euhedral crystals. Mineralization conditions at Tataouine might have offered some equivalent frozen intermediate states of the experiments by Kirkland et al (29).…”

Section: Discussion Relationships Between Calcite Precipitates and Pymentioning

confidence: 99%

“…An amorphous calcium carbonate phase is intrinsically unstable thermodynamically and kinetically at conditions similar to those prevailing at the surface of the Tataouine meteorite (34). The thin amorphous layer that is surrounding the crystals thus could be either the dissolution product of the calcite surface (29) or a precursor phase in the path of crystallization of calcite (see, e.g., ref. 35).…”

Section: Discussion Relationships Between Calcite Precipitates and Pymentioning

confidence: 99%

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Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite

Benzerara

Menguy

Guyot

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Nanobacteria-like objects evidenced at the surface of the orthopyroxenes of the Tataouine meteorite in South Tunisia have been studied by scanning and transmission electron microscopies. A method of micromanipulation has been developed to ensure that exactly the same objects were studied by both methods. We have shown that the nanobacteria-like objects are spatially correlated with filaments of microorganisms that colonized the surface of the meteoritic pyroxene during its 70 years of residence in the aridic Tataouine soil. Depressions of a few micrometers in depth are observed in the pyroxene below the carbonates, indicating preferential dissolution of the pyroxene and calcite precipitation at these locations. The nanobacteria-like small rods that constitute calcium carbonate rosettes are well crystallized calcite single crystals surrounded by a thin amorphous layer of carbonate composition that smoothes the crystal edges and induces rounded shapes. Those morphologies are unusual for calcite single crystals observed in natural samples. A survey of recent literature suggests that the intervention of organic compounds derived from biological activity is likely in their formation.

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Section: Discussion Relationships Between Calcite Precipitates and Pymentioning

confidence: 99%

Section: Discussion Relationships Between Calcite Precipitates and Pymentioning

confidence: 99%

Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite

Benzerara

Menguy

Guyot

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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“…Importantly, regarding average sizes of nanofibres, the hypothesis of the mineralization of rod-shaped bacteria suggests that these bacteria are rather nanobacteria. Yet, a controversy exists regarding the putative existence of nanobacteria (Folk, 1993;Kirkland et al, 1999;Folk and Lynch, 2001;Schieber and Arnott, 2003;Martel and Young, 2008;Young et al, 2009;Pacton and Gorin, 2011).…”

Section: Calcification Of Rod-shaped Bacteriamentioning

confidence: 99%

“…As already explained in the Sect. 2, a controversy is still ongoing regarding the existence of nanobacteria (Folk, 1993;Kirkland et al 1999;Folk and Lynch, 2001;Schieber and Arnott, 2003;Martel and Young, 2008;Young et al, 2009;Pacton and Gorin, 2011). Maniloff et al (1997) have defined that the lowest diameter for a cell to be viable must be 0.005 µm 3 .…”

Section: Critical Perspective On Alternative Hypotheses For the Origimentioning

confidence: 99%

Unravelling the enigmatic origin of calcitic nanofibres in soils and caves: purely physicochemical or biogenic processes?

et al. 2014

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Abstract. Calcitic nanofibres are ubiquitous habits of secondary calcium carbonate (CaCO 3 ) accumulations observed in calcareous vadose environments. Despite their widespread occurrence, the origin of these nanofeatures remains enigmatic. Three possible mechanisms fuel the debate: (i) purely physicochemical processes, (ii) mineralization of rod-shaped bacteria, and (iii) crystal precipitation on organic templates. Nanofibres can be either mineral (calcitic) or organic in nature. They are very often observed in association with needle fibre calcite (NFC), another typical secondary CaCO 3 habit in terrestrial environments. This association has contributed to some confusion between both habits, however they are truly two distinct calcitic features and their recurrent association is likely to be an important fact to help understanding the origin of nanofibres. In this paper the different hypotheses that currently exist to explain the origin of calcitic nanofibres are critically reviewed. In addition to this, a new hypothesis for the origin of nanofibres is proposed based on the fact that current knowledge attributes a fungal origin to NFC. As this feature and nanofibres are recurrently observed together, a possible fungal origin for nanofibres which are associated with NFC is investigated. Sequential enzymatic digestion of the fungal cell wall of selected fungal species demonstrates that the fungal cell wall can be a source of organic nanofibres. The obtained organic nanofibres show a striking morphological resemblance when compared to their natural counterparts, emphasizing a fungal origin for part of the organic nanofibres observed in association with NFC. It is further hypothesized that these organic nanofibres may act as templates for calcite nucleation in a biologically influenced mineralization process, generating calcitic nanofibres. This highlights the possible involvement of fungi in CaCO 3 biomineralization processes, a role still poorly documented. Moreover, on a global scale, the organomineralization of organic nanofibres into calcitic nanofibres might be an overlooked process deserving more attention to specify its impact on the biogeochemical cycles of both Ca and C.

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“…Reitner (2004) already pointed out that meteorites might contain abiotic organomineral products, which thus could not be regarded as biosignatures. Other authors have also shown that nonbiological organic molecules may induce the formation of minerals resembling the components of extraterrestrial bodies that are interpreted as biologically induced minerals, in particular fossilized 'nan(n)obacteria' (Kirkland et al, 1999;Cisar et al, 2000;Vali et al, 2001). Organominerals sensu Défarge and Trichet (1995), and more generally organiccontaining minerals, cannot be considered as indicators of life until the biotic origin of their organic components and their mechanism of formation have been unequivocally deciphered.…”

Section: Applications To the Search For Lifementioning

confidence: 99%

Defining organominerals: Comment on ‘Defining biominerals and organominerals: Direct and indirect indicators of life’ by Perry et al. (2007, Sedimentary Geology, 201, 157–179)

Défarge

Gautret

Reitner

et al. 2009

Sedimentary Geology

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The paper by Perry et al. (2007, Defining biominerals and organominerals: Direct and indirect indicators of life, Sedimentary Geology, 201, 157-179) proposes to introduce "the new term 'organomineral'" to describe mineral products whose formation is induced by byproducts of biological activity, dead and decaying organisms, or nonbiological organic compounds, to be distinguished from the biomineral components of living organisms. The substantive 'organomineral', however, is not new: it was first introduced in 1993, with basically the same definition and distinction from biominerals, at the 7th International Symposium on Biomineralization (Défarge and Trichet, 1995, From biominerals to

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Alternative origins for nannobacteria-like objects in calcite

Cited by 105 publications

References 0 publications

Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite

Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite

Unravelling the enigmatic origin of calcitic nanofibres in soils and caves: purely physicochemical or biogenic processes?

Defining organominerals: Comment on ‘Defining biominerals and organominerals: Direct and indirect indicators of life’ by Perry et al. (2007, Sedimentary Geology, 201, 157–179)

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