Serpentinite and the dawn of life

Sleep, Norman H.; Bird, Dennis K.; Pope, E. C.

doi:10.1098/rstb.2011.0129

Cited by 175 publications

(171 citation statements)

References 122 publications

(205 reference statements)

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“…Most of these candidate division members could be clustered into a clade with phylotypes reported from the oceanic serpentinizing site, Lost City (13,14,16), but not at the terrestrial sites. Considering that serpentinizing systems are globally distributed, and regarded by some as early (anoxic) earth analogs (30,31), this work may lead us to truly interesting members of the "early life" serpentinization community.…”

Section: Discussionmentioning

confidence: 99%

“…These phylotypes, clustered in candidate divisions or undescribed phyla, may have a special interest with regard to ancient life because they are mainly present in the strictly anaerobic serpentinizing source. Such groundwater sources are viewed as potential analogs for early ecosystems on both Earth and Mars, where there was no oxygen and where a highly reducing mineralogy was likely widespread (2,30,31). Euryarchaeota.…”

Section: Taxonomic Comparison Of Dominant Phylotypes In the Cedars Withmentioning

confidence: 99%

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Microbial diversity in The Cedars, an ultrabasic, ultrareducing, and low salinity serpentinizing ecosystem

Suzuki

Ishii

et al. 2013

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

111

204

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The Cedars, in coastal northern California, is an active site of peridotite serpentinization. The spring waters that emerge from this system feature very high pH, low redox potential, and low ionic concentrations, making it an exceptionally challenging environment for life. We report a multiyear, culture-independent geomicrobiological study of three springs at The Cedars that differ with respect to the nature of the groundwater feeding them. Within each spring, both geochemical properties and microbial diversity in all three domains of life remained stable over a 3-y period, with multiple samples each year. Between the three springs, however, the microbial communities showed considerable differences that were strongly correlated with the source of the serpentinizing groundwater. In the spring fed solely by deep groundwater, phylum Chloroflexi, class Clostridia, and candidate division OD1 were the major taxa with one phylotype in Euryarchaeota. Less-abundant phylotypes include several minor members from other candidate divisions and one phylotype that was an outlier of candidate division OP3. In the springs fed by the mixture of deep and shallow groundwater, organisms close to the Hydrogenophaga within Betaproteobacteria dominated and coexisted with the deep groundwater community members. The shallow groundwater community thus appears to be similar to those described in other terrestrial serpentinizing sites, whereas the deep community is distinctly different from any other previously described terrestrial serpentinizing community. These unique communities have the potential to yield important insights into the development and survival of life in these early-earth analog environments.biodiversity | extremophile | alkaliphile | small subunit rRNA | hydrogen

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Section: Discussionmentioning

confidence: 99%

Section: Taxonomic Comparison Of Dominant Phylotypes In the Cedars Withmentioning

confidence: 99%

Microbial diversity in The Cedars, an ultrabasic, ultrareducing, and low salinity serpentinizing ecosystem

Suzuki

Ishii

et al. 2013

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

111

204

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“…It is generally believed that the primordial atmosphere was CO 2 -dominated and that the atmospheric pressure was higher than it is now (67,68). Both these factors would boost the transportation of diverse ions by the ascending vapor.…”

Section: Vapor-dominated Zones Of Terrestrial Geothermal Systems Asmentioning

confidence: 99%

Origin of first cells at terrestrial, anoxic geothermal fields

Mulkidjanian

Bychkov²,

Dibrova³

et al. 2012

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

367

336

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All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energydependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the "hatcheries" of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K + , Zn 2+ , Mn 2+, and phosphate. Thus, protocells must have evolved in habitats with a high K + /Na + ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO 2 -dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K + , Zn 2+, and phosphorous compounds.

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“…On the early, uninhabited Earth, the main form of carbon was not glucose, glucose phosphate, ribose, glycogen, or starch, it was CO 2 (52). That is because the early Earth went through a phase where the planet was molten rock and metal, which is typically hotter than 1000°C and carbon in contact with the elements on the early Earth at such temperatures will exist as CO 2 , not as glucose or anything similar.…”

Section: Physiology Along Phylogeniesmentioning

confidence: 99%

Physiology, phylogeny, and the energetic roots of life

Martin

2017

Period Biol

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Before the days of molecular phylogenies, the standard way of viewing microbial evolution was as process of physiological evolution: the ordering of the sequence of events in which different pathways that microbes use to harness carbon and energy arose. The physiological view of microbial evolution was, of course, replaced in the 1980s by a gene centered view of microbial evolution that was built around the ribosomal RNA tree of life, also called the universal tree or the three domain tree. The universal tree installed long sought order into microbial systematics, but left physiological evolution out in the cold, because physiology never mapped properly onto the rRNA tree. LGT decoupLes physioLoGy from phyLoGeny T he foregoing quote from Dickerson (1) typifies a physiological view of evolution, one in which lateral gene transfer between prokaryotes is normal and distributes metabolic capabilities among lineages. Almost four decades later, the quote is still quite modern. It embodies a particular approach to understanding microbial evolution, a view from the standpoint of physiology -the chemical reactions at the core of carbon and energy metabolism that drive the process of life forward. Physiology is important in evolution, whether carbon (2, 3), sulfur (4, 5), nitrogen (6), or the geochemical context of physiology (7). Dickerson's quote also puts a very natural and nonchalant 1980s mention of lateral gene transfer (LGT) into the picture of microbial evolution as a common component of genetic variation among prokaryotes, long before people were debating the significance of LGT in prokaryote evolution. It even goes so far as to say that That was not because the universal tree had an incorrect branching pattern. Rather it was because physiological characters have never mapped neatly onto any phylogenetic tree for prokaryotes, regardless of its topology. The reason is that prokaryotes, though they have an undeniable tendency to vertically inherit their ribosome, distribute the physiological traits that enable synthesis of ribosomes via lateral gene transfer (LGT).LGT could possibly transform non-respiring lineages into respiring lineages via the transfer of many genes, something that we now know does actually occur during microbial evolution (8).Dickerson noted that the "evolutionary record" of microbes might have been scrambled. We have concepts about microbial evolution that are based on their evolutionary record, but what is the evolutionary record of microbes? What is it made of? It would appear that for microbial evolution there are only two kinds of records: geological and genomic. It is said that Earth records its own history (9), so do genomes. Putting geological and genomic evidence into a consistent picture of microbial evolution is a challenging undertaking, but that is the deliverable if we want a fuller picture of microbial evolution. Yet the only real connection between the two kinds of substance of the microbial evolutionary record -rocks and genes -is physiology. Physiology is arguably what...

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Serpentinite and the dawn of life

Cited by 175 publications

References 122 publications

Microbial diversity in The Cedars, an ultrabasic, ultrareducing, and low salinity serpentinizing ecosystem

Microbial diversity in The Cedars, an ultrabasic, ultrareducing, and low salinity serpentinizing ecosystem

Origin of first cells at terrestrial, anoxic geothermal fields

Physiology, phylogeny, and the energetic roots of life

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