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Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

Cousins C - Life (Basel) (2015)

Bottom Line: The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures.This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems.Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides).

View Article: PubMed Central - PubMed

Affiliation: UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK. c.cousins@ed.ac.uk.

ABSTRACT
The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

No MeSH data available.


Related in: MedlinePlus

Proportion of dissolved CO2 (77–1300 ppm), H2S (0.03–36.9 ppm), and SO42−(1.03–42.1 ppm) within East (A1–B4, data from [55]) and West (06-SKJ04, data from [53]) Skaftá subglacial lakes, and within the river Volga (Volga-C-1) and Hveragil (H-1 and H-4) outflows at Kverkfjöll (data from [55]. Upper plot shows total concentration for each respective site.
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life-05-00568-f003: Proportion of dissolved CO2 (77–1300 ppm), H2S (0.03–36.9 ppm), and SO42−(1.03–42.1 ppm) within East (A1–B4, data from [55]) and West (06-SKJ04, data from [53]) Skaftá subglacial lakes, and within the river Volga (Volga-C-1) and Hveragil (H-1 and H-4) outflows at Kverkfjöll (data from [55]. Upper plot shows total concentration for each respective site.

Mentions: Vatnajökull ice cap overlies several active or dormant central volcanic systems within the neovolcanic zone [49]. Of these volcanic systems, Grímsvötn has been regularly active, producing recent eruptions in 1996 (Gjálp), 1998, 2004 and 2011. The eruption observed in 1996 at Gjálp was entirely subglacial, resulting in meltwater ponding beneath the ice cap [50]. This process is common at volcano-ice interaction sites, with ongoing heat flux often maintaining a subglacial meltwater lake in between eruptions [51]. Several investigations have been conducted into the biogeochemical environment and indigenous microbiology of the subglacial lakes at Grímsvötn and at the nearby Skaftá lakes beneath Vatnajökull. In 2004 [52] sampled the subglacial lake confined within the Grímsvötn crater ~300 m beneath the ice surface and identified a viable microbial community residing within the lake. Results showed the −0.2 °C, oxic, mildly acidic (pH 4.87–5.13) lake supported a community of psychrotolerant bacteria, distinct from bacterial communities within the surrounding ice and snow, that was well adapted to a glacial environment. In contrast, the nearby geothermal subglacial lake at Western Skaftá forms a warmer (3.5–6 °C) anerobic environment within its bottom waters, with a measureable input of hydrothermal fluids into the lake [53]. As such, the microbial communities indigenous to the subglacial anoxic bottom waters here are dominated by obligate or facultative anaerobes including members of Acetobacterium, Thermus, Paludibacter, Sulfuricurvum, Pseudomonas, and Sulfurospirillum species, forming a microbial ecosystem potentially driven by sulfide oxidation, sulfate reduction, and hydrogen oxidation [54] utilizing the available CO2 and sulfide within the lake environment (Figure 3). A similar geochemical environment (Figure 3) and microbial community was identified at the Eastern Skaftá subglacial lake, with anoxic water characterized by mean dissolved H2S of 16 ppm and CO2 of 105 ppm [55] and a microbial population dominated by Acetobacterium, Geobacter, Sulfurospirillum, Sulfuricurvum and Desulfosporosinus species.


Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

Cousins C - Life (Basel) (2015)

Proportion of dissolved CO2 (77–1300 ppm), H2S (0.03–36.9 ppm), and SO42−(1.03–42.1 ppm) within East (A1–B4, data from [55]) and West (06-SKJ04, data from [53]) Skaftá subglacial lakes, and within the river Volga (Volga-C-1) and Hveragil (H-1 and H-4) outflows at Kverkfjöll (data from [55]. Upper plot shows total concentration for each respective site.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390869&req=5

life-05-00568-f003: Proportion of dissolved CO2 (77–1300 ppm), H2S (0.03–36.9 ppm), and SO42−(1.03–42.1 ppm) within East (A1–B4, data from [55]) and West (06-SKJ04, data from [53]) Skaftá subglacial lakes, and within the river Volga (Volga-C-1) and Hveragil (H-1 and H-4) outflows at Kverkfjöll (data from [55]. Upper plot shows total concentration for each respective site.
Mentions: Vatnajökull ice cap overlies several active or dormant central volcanic systems within the neovolcanic zone [49]. Of these volcanic systems, Grímsvötn has been regularly active, producing recent eruptions in 1996 (Gjálp), 1998, 2004 and 2011. The eruption observed in 1996 at Gjálp was entirely subglacial, resulting in meltwater ponding beneath the ice cap [50]. This process is common at volcano-ice interaction sites, with ongoing heat flux often maintaining a subglacial meltwater lake in between eruptions [51]. Several investigations have been conducted into the biogeochemical environment and indigenous microbiology of the subglacial lakes at Grímsvötn and at the nearby Skaftá lakes beneath Vatnajökull. In 2004 [52] sampled the subglacial lake confined within the Grímsvötn crater ~300 m beneath the ice surface and identified a viable microbial community residing within the lake. Results showed the −0.2 °C, oxic, mildly acidic (pH 4.87–5.13) lake supported a community of psychrotolerant bacteria, distinct from bacterial communities within the surrounding ice and snow, that was well adapted to a glacial environment. In contrast, the nearby geothermal subglacial lake at Western Skaftá forms a warmer (3.5–6 °C) anerobic environment within its bottom waters, with a measureable input of hydrothermal fluids into the lake [53]. As such, the microbial communities indigenous to the subglacial anoxic bottom waters here are dominated by obligate or facultative anaerobes including members of Acetobacterium, Thermus, Paludibacter, Sulfuricurvum, Pseudomonas, and Sulfurospirillum species, forming a microbial ecosystem potentially driven by sulfide oxidation, sulfate reduction, and hydrogen oxidation [54] utilizing the available CO2 and sulfide within the lake environment (Figure 3). A similar geochemical environment (Figure 3) and microbial community was identified at the Eastern Skaftá subglacial lake, with anoxic water characterized by mean dissolved H2S of 16 ppm and CO2 of 105 ppm [55] and a microbial population dominated by Acetobacterium, Geobacter, Sulfurospirillum, Sulfuricurvum and Desulfosporosinus species.

Bottom Line: The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures.This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems.Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides).

View Article: PubMed Central - PubMed

Affiliation: UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK. c.cousins@ed.ac.uk.

ABSTRACT
The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

No MeSH data available.


Related in: MedlinePlus