Using the phase diagram of liquid water to search for life

Jones, Eriita; Lineweaver, Charles H.

doi:10.1080/08120099.2011.591430

Cited by 8 publications

(5 citation statements)

References 91 publications

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“…Consideration of the limits represented by extremophiles may be interesting, but we suggest that it is also necessary to investigate how well life does in such extreme environments. This may take the form of phase diagrams used to assess habitable space (Jones & Lineweaver, 2012) that are enhanced by allowing for growth rates under multiple stressors. Habitability may then be better defined in terms of survival rather than reproduction (Cockell et al 2016) thus obtaining a larger parametric volume, but nevertheless, we suggest that interest should be centred on where life can do well, viz.…”

Section: Discussionmentioning

confidence: 99%

The maximum growth rate of life on Earth

Corkrey

McMeekin

Bowman

et al. 2017

International Journal of Astrobiology

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Life on Earth spans a range of temperatures and exhibits biological growth rates that are temperature dependent. While the observation that growth rates are temperature dependent is well known, we have recently shown that the statistical distribution of specific growth rates for life on Earth is a function of temperature (Corkrey et al., 2016). The maximum rates of growth of all life have a distinct limit, even when grown under optimal conditions, and which vary predictably with temperature. We term this distribution of growth rates the biokinetic spectrum for temperature (BKST). The BKST possibly arises from a trade-off between catalytic activity and stability of enzymes involved in a rate-limiting Master Reaction System (MRS) within the cell. We develop a method to extrapolate quantile curves for the BKST to obtain the posterior probability of the maximum rate of growth of any form of life on Earth. The maximum rate curve conforms to the observed data except below 0°C and above 100°C where the predicted value may be positively biased. The deviation below 0°C may arise from the bulk properties of water, while the degradation of biomolecules may be important above 100°C. The BKST has potential application in astrobiology by providing an estimate of the maximum possible growth rate attainable by terrestrial life and perhaps life elsewhere. We suggest that the area under the maximum growth rate curve and the peak rate may be useful characteristics in considerations of habitability. The BKST can serve as a diagnostic for unusual life, such as second biogenesis or non-terrestrial life. Since the MRS must have been heavily conserved the BKST may contain evolutionary relics. The BKST can serve as a signature summarizing the nature of life in environments beyond Earth, or to characterize species arising from a second biogenesis on Earth.

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Section: Discussionmentioning

confidence: 99%

The maximum growth rate of life on Earth

Corkrey

McMeekin

Bowman

et al. 2017

International Journal of Astrobiology

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“…In the current climate, this condition is never satisfied on the surface of Mars. Indeed, in the current climate the partial pressure of water vapor at the surface of Mars is below ∼1 Pa (Zent et al 2010;Jones and Lineweaver 2012;Savijärvi and Määttänen 2010). This value is two orders of magnitude lower than the saturation water vapor pressure at the triple point (611.73 Pa).…”

Section: Bulk Pure Liquid Water On the Surfacementioning

confidence: 95%

Water and Brines on Mars: Current Evidence and Implications for MSL

2013

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Liquid water is a basic ingredient for life as we know it. Therefore, in order to understand the habitability of other planets we must first understand the behavior of water on them. Mars is the most Earth-like planet in the solar system and it has large reservoirs of H 2 O. Here, we review the current evidence for pure liquid water and brines on Mars, and discuss their implications for future and current missions such as the Mars Science Laboratory.Neither liquid water nor liquid brines are currently stable on the surface of Mars, but they could be present temporarily in a few areas of the planet. Pure liquid water is unlikely to be present, even temporarily, on the surface of Mars because evaporation into the extremely dry atmosphere would inhibit the formation of the liquid phase, where the temperature and pressure are high enough so that water would neither freeze nor boil. The exception to this is that monolayers of liquid water, referred to as undercooled liquid interfacial water, could exist on most of the Martian surface. In a few places liquid brines could exist temporarily on the surface because they could form at cryogenic temperatures, near ice or frost deposits where sublimation could be inhibited by the presence of nearly saturated air.Both liquid water and liquid brines might exist in the shallow subsurface because even a thin layer of soil forms an effective barrier against sublimation allowing pure liquid water to form sporadically in a few places, or liquid brines to form over longer periods of time in large portions of the planet. At greater depths, ice deposits could melt where the soil conductivity is low enough to blanket the deeper subsurface effectively. This could cause the formation of aquifers if the deeper soil is sufficiently permeable and an impermeable layer exists below the source of water.The fact that liquid brines and groundwater are likely to exist on Mars has important implications for geochemistry, glaciology, mineralogy, weathering and the habitability of Mars.

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“…The current high-temperature limit for terrestrial life is *122°C (Kashefi and Lovley, 2003;Takai et al, 2008). The current low-temperature limit for active life is * -20°C ( Junge et al, 2004) and might be more correctly understood as a limit due to low water activity (Grant, 2004;Tosca et al, 2008;Jones and Lineweaver, 2011). The low mean geothermal gradient in the martian crust (*5 K/km compared to *25 K/km on Earth) and its variation (shown by the width of the phase model at a given depth) provide deep, cool environments not found on Earth (down to *10s of kilometers on Mars) that may be suitable for life (Pedersen, 2000;Chivian et al, 2008;Sherwood Lollar et al, 2009).…”

Section: The Pressure-temperature Phase Diagram Of Marsmentioning

confidence: 99%

“…The water activity of brines decreases sharply with decreasing temperatures below zero (Morillon et al, 1999); however, the analytical relationship for each salt is not known. Magnesium and calcium chloride and magnesium sulfate have activity < 0.35 at subzero temperatures (Table 1 in Jones and Lineweaver, 2011, and references therein), so they are not good candidates to support life. Salts such as magnesium nitrate and sodium bromide may also be able to support terrestrial life at temperatures as low as -30°C as the a w of the solution remains above 0.6; however, these salts may not be present on Mars ( Jones and Lineweaver, 2011).…”

Section: Liquid Water Phase Modelmentioning

confidence: 99%

“…Jones and Lineweaver, 2010, for Earth water). It has a freezing point depression of -100°C (Pearson and Derbyshire, 1974) at the triple point and is an estimate of the coldest possible liquid water on Mars (see Jones and Lineweaver, 2011). The details of our Mars model, including estimates of uncertainties and how the core (red), mantle (yellow), crust (light brown), and atmosphere (pink) were constructed, are described in Appendix A.…”

Section: The Pressure-temperature Phase Diagram Of Marsmentioning

confidence: 99%

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An Extensive Phase Space for the Potential Martian Biosphere

Jones

Lineweaver

Clarke³

2011

Astrobiology

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We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of *310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the *5 km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to *3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life.

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Using the phase diagram of liquid water to search for life

Cited by 8 publications

References 91 publications

The maximum growth rate of life on Earth

The maximum growth rate of life on Earth

Water and Brines on Mars: Current Evidence and Implications for MSL

An Extensive Phase Space for the Potential Martian Biosphere

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