Geothermal fields of Hengill Volcano, Iceland

Zakharova, Olga K.; Spichak, Viacheslav V.

doi:10.1134/s074204631201006x

Cited by 18 publications

(12 citation statements)

References 21 publications

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“…Some 50 km northeastward, the Hveragerdi geothermal region (Fig. 1d) is in direct connection with the active Hengill volcano by fissures swarms 50 . Rocks in this area are composed of subglacially formed hyaloclastite and interglacial basalt from lava flows, whereas montmorillonite is the dominant alteration clay mineral at shallow depths.…”

Section: Methodsmentioning

confidence: 99%

Fingerprinting molecular and isotopic biosignatures on different hydrothermal scenarios of Iceland, an acidic and sulfur-rich Mars analog

Sánchez-García

Carrizo

Molina

et al. 2020

Sci Rep

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Detecting signs of potential extant/extinct life on Mars is challenging because the presence of organics on that planet is expected to be very low and most likely linked to radiation-protected refugia and/or preservative strategies (e.g., organo-mineral complexes). With scarcity of organics, accounting for biomineralization and potential relationships between biomarkers, mineralogy, and geochemistry is key in the search for extraterrestrial life. Here we explored microbial fingerprints and their associated mineralogy in Icelandic hydrothermal systems analog to Mars (i.e., high sulfur content, or amorphous silica), to identify potentially habitable locations on that planet. The mineralogical assemblage of four hydrothermal substrates (hot springs biofilms, mud pots, and steaming and inactive fumaroles) was analyzed concerning the distribution of biomarkers. Molecular and isotopic composition of lipids revealed quantitative and compositional differences apparently impacted by surface geothermal alteration and environmental factors. pH and water showed an influence (i.e., greatest biomass in circumneutral settings with highest supply and turnover of water), whereas temperature conditioned the mineralogy that supported specific microbial metabolisms related with sulfur. Raman spectra suggested the possible coexistence of abiotic and biomediated sources of minerals (i.e., sulfur or hematite). These findings may help to interpret future Raman or GC–MS signals in forthcoming Martian missions.

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Section: Methodsmentioning

confidence: 99%

Fingerprinting molecular and isotopic biosignatures on different hydrothermal scenarios of Iceland, an acidic and sulfur-rich Mars analog

Sánchez-García

Carrizo

Molina

et al. 2020

Sci Rep

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“…The study was carried out in the Hengill geothermal area, 40 km east of Reykjavik, Iceland (64° 3' 11"N, 21° 18' 16"W; 360 m a.s.l.). This area is located at the base of the Hengill volcanic system, near to the Hrómundartindur and Hveragerði volcanic systems, where the Reykjanes Volcanic Zone, the West Volcanic Zone and the South Iceland Seismic Zone converge (Saemundsson, ; Zakharova & Spichak, ). The underlying bedrock of the study site contains geothermal channels originating from high volcanic activity common at tectonic boundaries (Zakharova & Spichak, ).…”

Section: Methodsmentioning

confidence: 99%

“…This area is located at the base of the Hengill volcanic system, near to the Hrómundartindur and Hveragerði volcanic systems, where the Reykjanes Volcanic Zone, the West Volcanic Zone and the South Iceland Seismic Zone converge (Saemundsson, 1992;Zakharova & Spichak, 2012). The underlying bedrock of the study site contains geothermal channels originating from high volcanic activity common at tectonic boundaries (Zakharova & Spichak, 2012). These channels warm the water and soil through radiative heating (Gudmundsdottir et al, 2011;Saemundsson, 1995).…”

Section: Study Systemmentioning

confidence: 99%

A natural heating experiment: Phenotypic and genotypic responses of plant phenology to geothermal soil warming

Valdés

Marteinsdóttir

Ehrlén

2018

Global Change Biology

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Under global warming, the survival of many populations of sedentary organisms in seasonal environments will largely depend on their ability to cope with warming in situ by means of phenotypic plasticity or adaptive evolution. This is particularly true in high‐latitude environments, where current growing seasons are short, and expected temperature increases large. In such short‐growing season environments, the timing of growth and reproduction is critical to survival. Here, we use the unique setting provided by a natural geothermal soil warming gradient (Hengill geothermal area, Iceland) to study the response of Cerastium fontanum flowering phenology to temperature. We hypothesized that trait expression and phenotypic selection on flowering phenology are related to soil temperature, and tested the hypothesis that temperature‐driven differences in selection on phenology have resulted in genetic differentiation using a common garden experiment. In the field, phenology was related to soil temperature, with plants in warmer microsites flowering earlier than plants at colder microsites. In the common garden, plants responded to spring warming in a counter‐gradient fashion; plants originating from warmer microsites flowered relatively later than those originating from colder microsites. A likely explanation for this pattern is that plants from colder microsites have been selected to compensate for the shorter growing season by starting development at lower temperatures. However, in our study we did not find evidence of variation in phenotypic selection on phenology in relation to temperature, but selection consistently favoured early flowering. Our results show that soil temperature influences trait expression and suggest the existence of genetically based variation in flowering phenology leading to counter‐gradient local adaptation along a gradient of soil temperatures. An important implication of our results is that observed phenotypic responses of phenology to global warming might often be a combination of short‐term plastic responses and long‐term evolutionary responses, acting in different directions.

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“…The geothermal activity in this area, mainly in the form of hot springs and fumaroles, originates from the Hengill volcanic system. This system is at the intersection of three volcanic zones: the Hengill, Hrómundartindur, and Hveragerði zones [ 49 , 50 ]. The temperature of soil is variable throughout the year, and the differences of temperature of the studied sites with respect normal temperature in soils (controls) is maintained throughout the year ( Figure 1 a).…”

Section: Methodsmentioning

confidence: 99%

Impact of Soil Warming on the Plant Metabolome of Icelandic Grasslands

et al. 2017

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Climate change is stronger at high than at temperate and tropical latitudes. The natural geothermal conditions in southern Iceland provide an opportunity to study the impact of warming on plants, because of the geothermal bedrock channels that induce stable gradients of soil temperature. We studied two valleys, one where such gradients have been present for centuries (long-term treatment), and another where new gradients were created in 2008 after a shallow crustal earthquake (short-term treatment). We studied the impact of soil warming (0 to +15 °C) on the foliar metabolomes of two common plant species of high northern latitudes: Agrostis capillaris, a monocotyledon grass; and Ranunculus acris, a dicotyledonous herb, and evaluated the dependence of shifts in their metabolomes on the length of the warming treatment. The two species responded differently to warming, depending on the length of exposure. The grass metabolome clearly shifted at the site of long-term warming, but the herb metabolome did not. The main up-regulated compounds at the highest temperatures at the long-term site were saccharides and amino acids, both involved in heat-shock metabolic pathways. Moreover, some secondary metabolites, such as phenolic acids and terpenes, associated with a wide array of stresses, were also up-regulated. Most current climatic models predict an increase in annual average temperature between 2–8 °C over land masses in the Arctic towards the end of this century. The metabolomes of A. capillaris and R. acris shifted abruptly and nonlinearly to soil warming >5 °C above the control temperature for the coming decades. These results thus suggest that a slight warming increase may not imply substantial changes in plant function, but if the temperature rises more than 5 °C, warming may end up triggering metabolic pathways associated with heat stress in some plant species currently dominant in this region.

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Geothermal fields of Hengill Volcano, Iceland

Cited by 18 publications

References 21 publications

Fingerprinting molecular and isotopic biosignatures on different hydrothermal scenarios of Iceland, an acidic and sulfur-rich Mars analog

Fingerprinting molecular and isotopic biosignatures on different hydrothermal scenarios of Iceland, an acidic and sulfur-rich Mars analog

A natural heating experiment: Phenotypic and genotypic responses of plant phenology to geothermal soil warming

Impact of Soil Warming on the Plant Metabolome of Icelandic Grasslands

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