Bodies Of Liquid Water Research Articles

Subglacial Environments and the Search for Life Beyond the Earth

One of the most remarkable discoveries resulting from the robotic and remote sensing exploration of space is the inferred presence of bodies of liquid water under ice deposits on other planetary bodies: extraterrestrial subglacial environments. Most prominent among these are the ice-covered ocean of the Jovian moon, Europa, and the Saturnian moon, Enceladus. On Mars, although there is no current evidence for subglacial liquid water today, conditions may have been more favorable for liquid water during periods of higher obliquity. Data on these extraterrestrial environments show that while they share similarities with some subglacial environments on the Earth, they are very different in their combined physicochemical conditions. Extraterrestrial environments may provide three new types of subglacial settings for study: (1) uninhabitable environments that are more extreme and life-limiting than terrestrial subglacial environments, (2) environments that are habitable but are uninhabited, which can be compared to similar biotically influenced subglacial environments on the Earth, and (3) environments with examples of life, which will provide new opportunities to investigate the interactions between a biota and glacial environments.

Structure and life cycle of supraglacial lakes in Dronning Maud Land

AbstractSupraglacial lakes form in Antarctic blue ice regions from penetration of solar radiation into the ice in summer. Three lakes were mapped for their structure in summers 2004–05 and 2010–11 in western Dronning Maud Land, and one was also examined for the radiation budget. The lake body consisted of two layers, each ∼1 m thick: an upper layer with a thin ice layer on top and main body of liquid water, and a lower layer containing slush and hard ice sub-layers. A sediment-rich slush pocket was found at the bottom. Hydraulic conductivity of the lake body was 0.25–30 cm s-1 depending on the stage of evolution, with 6.3 cm s-1 for closely packed slush. Albedo of the lake was 0.4–0.6 and light attenuation coefficient was 0.5–0.7 m-1. The formation and the depth scale of the lakes are determined by the light attenuation distance and thermal diffusion coefficient, limiting the growth to less than about 1.5 m in one summer. The potential winter growth is more and thus the lakes freeze up in winter in the present climatic conditions.

A review on the spontaneous formation of the building blocks of life and the generation of a set of hypotheses governing universal abiogenesis

AbstractThere have been a number of hypotheses regarding abiogenesis, the ‘Metabolism First’ model and the ‘RNA World Hypothesis’ are two such examples. All theories on abiogenesis make a set of unstated assumptions with regard to the elemental make up of life or only apply the theory to a primitive earth model. This paper reviews current knowledge from the myriad of observations from a variety of scientific disciplines and applies generally understood thermodynamic reasoning to explain the formation of molecules known to be used by life. These arguments are used in this paper to construct a set of new hypotheses which govern universal abiogenesis. The intention of this paper is to show by the application of our known laws of science that life is the end sequence of events of the fundamental forces which affect the entire universe. From these events a new hypotheses on abiogenesis can be formulated. The hypotheses proposed by this paper are incorporated in many of the current theories of abiogenesis, either assumed or accepted but very rarely stated or explained. The proposed set of five hypotheses are: (1) any celestial mass that has a body of liquid water and therefore has access to energy will form at least the building blocks of life, if not life itself. (2) The major component of any life form anywhere in the universe will be H2O. (3) Any organism, anywhere in the universe, will be carbon-based. (4) All life in the universe will be composed of nucleic acid based molecules as its code for life. (5) The cell is the universal unit of life. Throughout this paper the background to the formulation of these hypotheses is discussed, as is the explanation of why these hypotheses are universal and not limited to an application of a primitive earth model. This set of hypotheses is also testable as any investigation of a celestial body which contains liquid water (e.g. Europa) will quickly provide evidence to prove or refute the proposed theory.

A large sedimentary basin in the Terra Sirenum region of the southern highlands of Mars

Different lines of evidence point to hydrological cycling in the martian past. The extent, duration, and magnitude of this cycling remains unclear, as well as the magnitude of aqueous processes on the surface. Here, we provide geomorphic and mineralogic evidence of a large inter-crater sedimentary basin located in the Terra Sirenum region, which was once covered by a body of liquid water with an areal extent of at least 30,000 km 2 and a depth of approximately 200 m. The topographic basin, which is modified by a number of large impact craters, is partly controlled by ancient impact and tectonic structures. As a result of evaporation of the large body of water, salt flats formed in the lowest topographic reaches of the basin. Hydrated phyllosilicates occur in close proximity to the salt flats and in the ejecta and rim materials of small impact craters with stratigraphic relations that suggest that they underlie the evaporite deposits. Crater statistics place the maximum age of aqueous activity during the Late Noachian epoch. The relatively pristine mineral deposits in the basin have a high potential to yield information of the geochemistry and water activity during the ancient Noachian Period when conditions were seemingly more conducive to life.

EVOLUTION OF THE SOLAR ACTIVITY OVER TIME AND EFFECTS ON PLANETARY ATMOSPHERES. II. κ1Ceti, AN ANALOG OF THE SUN WHEN LIFE AROSE ON EARTH

The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigation of the atmospheric parameters, state of evolution and high-energy fluxes of the nearby star kap^1 Cet, previously thought to have properties resembling those of the early Sun. Atmospheric parameters were derived from the excitation/ionization equilibrium of Fe I and Fe II, profile fitting of Halpha and the spectral energy distribution. The UV irradiance was derived from FUSE and HST data, and the absolute chromospheric flux from the Halpha line core. From careful spectral analysis and the comparison of different methods we propose for kap^1 Cet the following atmospheric parameters: Teff = 5665+/-30 K (Halpha profile and energy distribution), log g = 4.49+/-0.05 dex (evolutionary and spectroscopic) and [Fe/H] = +0.10+/-0.05 dex (Fe II lines). The UV radiative properties of kap^1 Cet indicate that its flux is some 35% lower than the current Sun's between 210 and 300 nm, it matches the Sun's at 170 nm and increases to at least 2-7 times higher than the Sun's between 110 and 140 nm. The use of several indicators ascribes an age to kap^1 Cet in the interval ~0.4-0.8 Gyr and the analysis of the theoretical HR diagram suggests a mass ~1.04 Msun. This star is thus a very close analog of the Sun when life arose on Earth and Mars is thought to have lost its surface bodies of liquid water. Photochemical models indicate that the enhanced UV emission leads to a significant increase in photodissociation rates compared with those commonly assumed of the early Earth. Our results show that reliable calculations of the chemical composition of early planetary atmospheres need to account for the stronger solar photodissociating UV irradiation.

Ismenius Cavus, Mars: A deep paleolake with phyllosilicate deposits

Ismenius Cavus is a basin where several fluvial valleys converge. Three depositional fan deltas are observed at the valleys outlets at similar elevations. These fans suggest long-term fluvial activity accompanied by a lake inside the basin. The elevational difference between the delta plains and the deepest part of the basin floor implies that this lake was 600 m deep. Iron–magnesium phyllosilicates, which are mapped from near-infrared spectral data, are associated with layered sediments >300 m thick at the base of one of the fans. Stratigraphic relationships with the surrounding plateau show that the valleys are hesperian in age (3.0–3.7 ga), thus dating the lake activity to this period. The coexistence of a deep lake and phyllosilicates demonstrates that persistent bodies of liquid water were present during the hesperian period.

Is the Martian water table hidden from radar view?

Mars may possess a global sub‐surface groundwater table as an integral part of its current hydrological system. However, the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the Mars Express (MEx) spacecraft has yet to make a definitive detection of such a body of liquid water. In this work, we quantify the conditions that would allow a detection of a deep aquifer and demonstrate that the lack of radar detection does not uniquely rule out the presence of such a body. Specifically, if the overlying crustal material has a conductivity above ∼10−5 S/m (equivalent to a loss tanget of 0.008), a radar echo from an aquifer could be sufficiently attenuated by the intervening medium to prevent its detection by MARSIS. As such, the lack of direct detection by MARSIS–a “null result”–does not rule out the possibility of the water table's existence.

Venus, Mars, and the Ices on Mercury and the Moon: Astrobiological Implications and Proposed Mission Designs

Venus and Mars likely had liquid water bodies on their surface early in the Solar System history. The surfaces of Venus and Mars are presently not a suitable habitat for life, but reservoirs of liquid water remain in the atmosphere of Venus and the subsurface of Mars, and with it also the possibility of microbial life. Microbial organisms may have adapted to live in these ecological niches by the evolutionary force of directional selection. Missions to our neighboring planets should therefore be planned to explore these potentially life-containing refuges and return samples for analysis. Sample return missions should also include ice samples from Mercury and the Moon, which may contain information about the biogenic material that catalyzed the early evolution of life on Earth (or elsewhere). To obtain such information, science-driven exploration is necessary through varying degrees of mission operation autonomy. A hierarchical mission design is envisioned that includes spaceborne (orbital), atmosphere (airborne), surface (mobile such as rover and stationary such as lander or sensor), and subsurface (e.g., ground-penetrating radar, drilling, etc.) agents working in concert to allow for sufficient mission safety and redundancy, to perform extensive and challenging reconnaissance, and to lead to a thorough search for evidence of life and habitability.

Weathering of iron-rich phases in simulated Martian atmospheres

Research Article| December 01, 2004 Weathering of iron-rich phases in simulated Martian atmospheres Vincent Chevrier; Vincent Chevrier 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Search for other works by this author on: GSW Google Scholar Pierre Rochette; Pierre Rochette 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Search for other works by this author on: GSW Google Scholar Pierre-Etienne Mathé; Pierre-Etienne Mathé 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Search for other works by this author on: GSW Google Scholar Olivier Grauby Olivier Grauby 2Centre de Recherche en Matière Condensée et Nanosciences, Centre National de la Recherche Scientifique, Campus de Luminy, case 913, 13288 Marseille cedex 13, France Search for other works by this author on: GSW Google Scholar Author and Article Information Vincent Chevrier 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Pierre Rochette 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Pierre-Etienne Mathé 1Centre Européen de Recherche et d'Enseignement en Géosciences de l′Environnement, Europôle de l′Arbois, BP 80, 13545 Aix-en-Provence, cedex 04, France Olivier Grauby 2Centre de Recherche en Matière Condensée et Nanosciences, Centre National de la Recherche Scientifique, Campus de Luminy, case 913, 13288 Marseille cedex 13, France Publisher: Geological Society of America Received: 12 Aug 2004 Revision Received: 24 Aug 2004 Accepted: 31 Aug 2004 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (12): 1033–1036. https://doi.org/10.1130/G21078.1 Article history Received: 12 Aug 2004 Revision Received: 24 Aug 2004 Accepted: 31 Aug 2004 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Vincent Chevrier, Pierre Rochette, Pierre-Etienne Mathé, Olivier Grauby; Weathering of iron-rich phases in simulated Martian atmospheres. Geology 2004;; 32 (12): 1033–1036. doi: https://doi.org/10.1130/G21078.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract In order to simulate the weathering of primary phases likely to occur on the Martian surface, metallic iron α-Fe, magnetite, and pyrrhotite were aged in CO2 + H2O or CO2 + H2O2 atmospheres at room temperature for 1 yr. Only the magnetite remained stable during experiments; thus any magnetite on Mars is likely to be inherited from primary bedrock, whereas any metallic and most sulfide iron minerals are provided by meteoritic accretion. Metastable siderite, neoformed from α-Fe, as well as sulfates and sulfur from pyrrhotite, account for various Martian in situ observations. Stepwise color changes are related either to changes in the relative proportions of neoformed phases or to atmosphere-related changes in crystallinity, rather than to fundamental mineralogical variations of iron phases. Goethite is the main crystalline iron-bearing end product, eventually associated with ferrihydrite. If hematite is the actual dominant iron oxide that colors the Red Planet, our results imply strong changes in water activities of the primary CO2 and H2O rich atmosphere (i.e., evolution toward anhydrous conditions), or long-term evolution, for goethite to further convert into hematite. Our experiments suggest that iron weathering may have been active until recent times and would not have required bodies of liquid water. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

On the thermodynamic efficiency of energy conversion during the expansion of a mixture of hot particles, steam and liquid water

When an amount of high-temperature molten material is suddenly and finely mixed with a body of liquid water, the ensuing mixture expands because of the volumetric generation of steam. At the same time, the expanding mixture is accelerated away from the surfaces with which it comes in contact. In this paper, we address the fundamental thermodynamic aspects of the energy-conversion process, with emphases on the energy-conversion efficiency and the impact of the intensity of the heat-transfer irreversibility on decreasing the efficiency. The expanding mixture is modeled as a conglomerate of spherical drops of molten material distributed uniformly throughout a body of water. At the elemental level, steam annuli develop around the spherical drops as time increases. At the mixture level, the density decreases while the pressure and velocity increase. The energy-conversion process is simulated numerically, and results are reported for the evolution of a mixture layer bounded on one side by an impermeable plane wall. The energy conversion efficiency is in the 10−2–10−3 range. The effects of physical parameters such as droplet and waterlayer sizes are discussed.

Bodies of liquid water as a source of water gain for Ixodes ricinus ticks (Acari: Ixodidae)

It is well established that free-living unfed ticks can compensate for their inevitable body water losses by active water vapour absorption in periods of ambient relative humidity (RH) of greater than 75-90%. Whilst many species of terrestrial arthropods are known to be capable of locating liquid water and drinking when in need, the existing knowledge concerning the ecological significance of bulk water for rehydration in ticks is scarce. In the present laboratory study batches of unfed Ixodes ricinus (larvae, nymphs, and adults) in varying states of (de)hydration were supplied with tapwater either as droplets for 45 min in a Petri dish or in a small trough for 24 h. The body mass of each tick was gravimetrically determined before and after exposure. Though fully hydrated ticks were not usually attracted to liquid water, the response became increasingly positive with a growing body water deficit (p > 0.05). No tick was ever found with its mouthparts inserted into the water, nor had any tick residues of orange G in its alimentary tract when supplied with orange G-coloured water. Linear regression analysis demonstrated that water intake took place in a regulated manner in adult ticks, i.e. the more severely the ticks had been dehydrated the more net water they subsequently gained (p > 0.01). The maximum uptake rates were <20% of the original body mass per day. These findings indicate that unfed I. ricinus do not drink liquid water but are well able to use the high RH in the immediate vicinity of bulk water to actively take up vapour.

Duration of liquid water habitats on early Mars

We have employed a simple climate model of early Mars in order to estimate the duration of ice-covered lakes after the onset of freezing conditions on Mars. The critical parameter determining the existence of ice-covered lakes is the existence of peak seasonal temperatures above freezing. The peak temperature occurs at the subsolar point at perihelion. We use the weathering model of Pollack et al. ( Icarus 71, 203–224, 1987) to compute the pressure and temperature evolution of the atmosphere. We have included the variability of the solar luminosity. We find that if there was a source of ice to provide meltwater, liquid water habitats could have been maintained under relatively thin ice covers for up to 700 million years after mean global temperatures fell below the freezing point. At this point, the mean annual temperature is 227 K, and the pressure of atmospheric CO 2 is about 0.5 bar. Without the presence of stable bodies of liquid water, it is not clear what mechanisms were responsible for the removal of this remaining CO 2. From a biological point of view, we find that the duration of liquid water habitats on early Mars exceeds the upper limit on the time required for the origin of life on Earth.

Planetary science: Hidden carbon dioxide on Mars

A recent proposal that much of the outgassed CO2 on Mars is tied up in the planet's crust in the form of carbonate mineral is discussed. According to this hypothesis, carbonate formation on Mars continued after open bodies of liquid water became unstable. A consequence of the hypothesis is that, in the absence of a recycling mechanism for CO2, the surface pressure on Mars will monotonically decrease until it reaches the minimum atmospheric overburden pressure required for liquid water to form. The theory explains Mars' low surface pressure, and also implies that the climate of Mars has evolved linearly over geologic time, rather than cyclically.

The evolution of CO 2 on Mars

At an average location on the surface of Mars, the pressure of CO 2 ( P CO 2 ) varies seasonally between about 6 and 8 mbar. Outgassing models suggest that at least 140 mbar, and possibly as much as 3000 mbar, of CO 2 have been placed in the atmosphere over geologic time. Neither the polar caps nor the regolith alone appears to be an adequate repository for the CO 2. The north polar cap does not contain a permanent store of CO 2 ice, while the south polar cap is unlikely to hold in excess of a few millibars. The regolith can adsorb no more, and probably much less, than 280 mbar of CO 2. Mechanisms associated with storing carbon in these reservoirs do not account for the particular range and stability of P CO 2 found on Mars today. It is argued that carbonate rock is the most reasonable reservoir for the excess CO 2 and that the rock formation process can explain the current CO 2 pressure. To effect carbonate formation at a rate rapid enough to produce significant deposits over geologic time, liquid water, at least in transitory pockets, is apparently required. Solid-solid and solid-gas reactions are probably orders of magnitude too slow; however, even intermittent aqueous chemistry may be sufficient. Cations are also needed, and existing constraints on the chemical state of the Martian soil do not preclude their occurrence in usable forms and adequate supply. A feedback mechanism that links the evolution of P CO 2 directly to the occurrence of liquid water is postulated. According to the scenario, the evolution of P CO 2 is controlled largely by aqueous chemistry forming carbon-containing sedimentary rocks as on Earth, perhaps during early history in open water, but more recently in transitory pockets of moisture in the soil. Once the total atmospheric pressure is reduced to near a limiting value ( P ★), below which liquid water can not form in the Mars environment, the occurrence of transitory pockets is inhibited, and atmospheric CO 2 is no longer depleted by an efficient mechanism. While present conditions on Mars preclude the existence of open bodies of liquid water, the formation of moisture in disequilibrium is not excluded by any known constraints. To a first approximation, the water evaporation rate is inversely proportional to P CO 2 , which suggests the existence of a minimum overburden pressure P ★. Calculations showing that it is difficult but not impossible to form liquid water in disequilibrium on Mars today support the argument that a limiting value of P CO 2 has been approached. P CO 2 is currently quite close to the triple-point pressure of water, which is the minimum equilibrium vapor pressure of water above the pure liquid. This too is in accord with the hypothesis, given existing constraints on current Martian conditions, since the minimum disequilibrium overburden pressure is unlikely to be lower, but need not be much higher, than the triple-point pressure of water if a feedback mechanism of the type proposed is operating. To form transitory pockets of pure liquid water, the smallest possible value of P ★ is loosely constrained to 6.1 mbar by the minimum criterion, in a space- and time-averaged sense, for which very rapid evaporation of ice would occur until open liquid water could be maintained in equilibrium on the surface. From a consideration of available insolation at Mars, a very crude upper bound on P ★ of around 30 mbar is obtained. The hypothesis has profound implications for the history of the Mars surface and atmosphere. It suggests that unless rapid outgassing events occurred subsequent to early Mars times, the climate of the planet has, to first order, evolved linearly, rather than in the cyclic manner allowed by polar cap storage or some models of regolith adsorption reservoirs. Substantial carbonate deposits are predicted, though they may be mixed in the soil or covered by eolian debris. If these deposits can be mapped on a global scale, their spatial distribution should contain clues about the way heat and water needed for sedimentation are supplied.

Thermodynamics of heterogeneous iron—Carbon systems: Implications for the terrestrial primitive reducing atmosphere

I consider the problem of the early-earth surface—atmosphere chemical environment in which initial biochemical synthesis occurred. The model of a strongly reducing atmosphere developed by Oparin, Miller and others is reviewed and reasons for doubting its validity given. As an alternative, I propose that the primary source of carbon for biochemical genesis on the early earth was CO 2 and the fundamental chemical process was reduction by ferrous ion in the primitive ocean, for which radiation was required as an initiator but not as a source of free energy. The formation of reduced C compounds, including the biologically important amino acids, is shown to be a thermodynamically spontaneous process in the heterogeneous system comprising CO 2 and N 2 at reasonable pressure in contact with Fe (II)-containing minerals likely to have been present in abundance on the early earth. Possible mechanisms for formation reactions are considered, and an early role for primitive ferredoxin-type redox catalysts is postulated. The suggested early-earth environment was similar to that apparently present on Mars, except for the absence of large permanent bodies of liquid water on the latter.

Reducing greenhouses and the temperature history of Earth and Mars

THE modern theory of stellar evolution implies that the Sun has increased in brightness by several tens of per cent over geological time. Were all other global parameters held constant, this would imply that the mean temperature of the Earth was below the freezing point of seawater about 2×109 yr ago1. There is, however, excellent geological and palaeontological evidence that there were extensive bodies of liquid water on the Earth between 3 and 4×109 yr ago, A possible solution to this puzzle, first postulated by Sagan and Mullen1, is that the Earth's primitive atmosphere contained small quantities of NH3 and other reducing gases which significantly enhanced the global greenhouse effect. NH3 is especially effective in the 8–13 µm window in a CO2—H2O atmosphere. It was argued that plausible changes in other global parameters, such as the infrared emissivity or the Russell–Bond albedo, would have been ineffective. The increase in solar brightness over geological time seems model-invariant even under extreme model perturbation for the solar interior1, as has recently been reconsidered in a straightforward stellar structure scaling argument2, Cosmochemical considerations point strongly to a higher abundance of reduced constituents in the primitive than in the contemporary terrestrial atmosphere; and reduced atmospheric components such as NH3 and CH4 are required to understand the accumulation of prebiological organic compounds necessary for the origin of life in this same period, between 3 and 4×109 yr ago3.

A nongrey calculation of the runaway greenhouse: Implications for Venus' past and present

Abstract We obtain the dependence of the surface temperature of a planet covered with bodies of liquid water upon the amount of incident solar flux. To determine this relationship we carry out nongrey calculations of both the thermal flux emitted to space and the planetary albedo. Water vapor is the only source of infrared opacity in our models. For most of the model atmospheres with a 50% cloud cover, the solar flux incident upon Venus at the present time is sufficiently high to cause complete evaporation of any hypothetical oceans, thus assuring that any carbon dioxide outgassed into the atmosphere remains there. However, our models with a 100% cloud cover do not achieve runaway conditions. Our calculations indicate that four and a half billion years ago, when the solar luminosity was 30% lower than its present value, Venus may have had a very moderate surface temperature and bodies of liquid water on its surface.