scholarly journals Terrimonas crocea sp. nov., isolated from the till of a high Arctic glacier

2017 ◽  
Vol 67 (4) ◽  
pp. 868-874 ◽  
Author(s):  
Myong Chol Kim ◽  
Ok Chol Kang ◽  
Chol Myong Kim ◽  
Yumin Zhang ◽  
Zuobing Liu ◽  
...  
Keyword(s):  
High Arctic ◽  
Arctic Glacier

scholarly journals Solute in high arctic glacier snow cover and its impact on runoff chemistry

1998 ◽  
Vol 26 ◽  
pp. 156-160 ◽  
Author(s):  
Richard Hodgkins ◽  
Martyn Tranter
Keyword(s):  
Chemical Composition ◽  
Atmospheric Transport ◽  
Total Concentration ◽  
High Arctic ◽  
Sea Salt ◽  
Acidic Ph ◽  
Sea Salt Aerosol ◽  
Wet Snow ◽  
Potential Contributor ◽  
Arctic Glacier

The chemical composition of snow and meltwater in the 13 km2 catchment of Scott Turnerbreen, Svalbard, was investigated during the spring and summer of 1993. This paper assesses the provenance of solute in the snowpack and its impact on runoff chemistry. Dry snow contains 420μeql-1 of solute, is slightly acidic (pH 5.4) and is dominated by Na+ and Cl-. Wet snow is more dilute (total concentration 340μeql-1), and less acidic (pH 5.9). This is consistent with the elution of ions from the snowpack by meltwater. Snowpack solute can be partitioned into the following fractions: sea-salt aerosol, acid aerosol and crustal. About 98% of snowpack solute is sea salt, yielding 22000 kg km-2a-1. The behaviour of snowpack-derived Cl- in runoff is distinctive, peaking at over 800 μeql-1 early in the melt season as runoff picks up, before declining quasi-exponentially. This represents the discharge of snowmelt concentrated by elution within the snowpack which subsequently becomes relatively dilute. A solute yield of 140 kg km-2 a-1 can be attributed to anthropogenically generated acid aerosols, representing long-range atmospheric transport of pollutants, a potential contributor to Arctic runoff acidification.

scholarly journals Effects of substrate differences on water availability for Arctic lichens during the snow-free summers in the High Arctic glacier foreland

Polar Science ◽  
2014 ◽  
Vol 8 (4) ◽  
pp. 397-412 ◽  
Author(s):  
Takeshi Inoue ◽  
Sakae Kudoh ◽  
Masaki Uchida ◽  
Yukiko Tanabe ◽  
Masakane Inoue ◽  
...  
Keyword(s):  
Water Availability ◽  
High Arctic ◽  
Glacier Foreland ◽  
Arctic Glacier

scholarly journals Intra-annual and intra-seasonal flow dynamics of a High Arctic polythermal valley glacier

2003 ◽  
Vol 37 ◽  
pp. 181-188 ◽  
Author(s):  
Robert G. Bingham ◽  
Peter W. Nienow ◽  
Martin J. Sharp
Keyword(s):  
Drainage System ◽  
High Arctic ◽  
Ablation Zone ◽  
Accumulation Zone ◽  
Seasonal Flow ◽  
Excess Surface ◽  
Velocity Response ◽  
Spatio Temporal ◽  
June July ◽  
Arctic Glacier

AbstractMeasurements of surface dynamics on polythermal John Evans Glacier, Nunavut, Canada, over two winter periods and every 7–10 days throughout two melt seasons (June–July 2000, 2001) provide new insight into spatio-temporal patterns of High Arctic glacier dynamics. In the lower ablation zone, mean annual surface velocities are 10–21 m a–1, but peak velocities up to 50% higher are attained during late June/early July. In the upper ablation zone and lower accumulation zone, mean annual surface velocities are typically 10–18 m a–1, and peak velocities up to 40% higher occur during late July. In the upper accumulation zone, mean annual surface velocities are 2–9 m a–1, and motion in mid- to late July exceeds this by up to 10%. Rapid drainage of ponded supraglacial water in the upper ablation zone to an initially distributed subglacial drainage system in mid-June may force excess surface motion in the warm-based lower glacier. The data indicate that the duration of the velocity response may be related to the rate of channelization of the basal drainage, and the velocity response may be transmitted up-glacier by longitudinal coupling. An increase in surface velocities in the middle glacier in late July occurs in conjunction with the opening of two further moulins in the accumulation zone.

scholarly journals Potential Rhodopsin- and Bacteriochlorophyll-Based Dual Phototrophy in a High Arctic Glacier

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Yonghui Zeng ◽  
Xihan Chen ◽  
Anne Mette Madsen ◽  
Athanasios Zervas ◽  
Tue Kjærgaard Nielsen ◽  
...  
Keyword(s):  
Solar Energy ◽  
Energy Production ◽  
Gene Clusters ◽  
High Arctic ◽  
Proton Pumping ◽  
The Other ◽  
Life Strategy ◽  
Metabolic Potential ◽  
Expression Control ◽  
Arctic Glacier

ABSTRACT Conserving additional energy from sunlight through bacteriochlorophyll (BChl)-based reaction center or proton-pumping rhodopsin is a highly successful life strategy in environmental bacteria. BChl and rhodopsin-based systems display contrasting characteristics in the size of coding operon, cost of biosynthesis, ease of expression control, and efficiency of energy production. This raises an intriguing question of whether a single bacterium has evolved the ability to perform these two types of phototrophy complementarily according to energy needs and environmental conditions. Here, we report four Tardiphaga sp. strains (Alphaproteobacteria) of monophyletic origin isolated from a high Arctic glacier in northeast Greenland (81.566° N, 16.363° W) that are at different evolutionary stages concerning phototrophy. Their >99.8% identical genomes contain footprints of horizontal operon transfer (HOT) of the complete gene clusters encoding BChl- and xanthorhodopsin (XR)-based dual phototrophy. Two strains possess only a complete XR operon, while the other two strains have both a photosynthesis gene cluster and an XR operon in their genomes. All XR operons are heavily surrounded by mobile genetic elements and are located close to a tRNA gene, strongly signaling that a HOT event of the XR operon has occurred recently. Mining public genome databases and our high Arctic glacial and soil metagenomes revealed that phylogenetically diverse bacteria have the metabolic potential of performing BChl- and rhodopsin-based dual phototrophy. Our data provide new insights on how bacteria cope with the harsh and energy-deficient environment in surface glacier, possibly by maximizing the capability of exploiting solar energy. IMPORTANCE Over the course of evolution for billions of years, bacteria that are capable of light-driven energy production have occupied every corner of surface Earth where sunlight can reach. Only two general biological systems have evolved in bacteria to be capable of net energy conservation via light harvesting: one is based on the pigment of (bacterio-)chlorophyll and the other is based on proton-pumping rhodopsin. There is emerging genomic evidence that these two rather different systems can coexist in a single bacterium to take advantage of their contrasting characteristics in the number of genes involved, biosynthesis cost, ease of expression control, and efficiency of energy production and thus enhance the capability of exploiting solar energy. Our data provide the first clear-cut evidence that such dual phototrophy potentially exists in glacial bacteria. Further public genome mining suggests this understudied dual phototrophic mechanism is possibly more common than our data alone suggested.

scholarly journals A cross-validated three-dimensional model of an englacial and subglacial drainage system in a High-Arctic glacier

2020 ◽  
Vol 66 (256) ◽  
pp. 278-290
Author(s):  
Lena U. Hansen ◽  
Jan A. Piotrowski ◽  
Douglas I. Benn ◽  
Heidi Sevestre
Keyword(s):  
Three Dimensional ◽  
Drainage System ◽  
High Arctic ◽  
Water Drainage ◽  
Three Dimensional Model ◽  
Closure Mechanism ◽  
Ground Penetrating ◽  
Arctic Glacier ◽  
D Model ◽  
Englacial Drainage

AbstractRecent speleological surveys of meltwater drainage systems in cold and polythermal glaciers have documented dynamic englacial and in some cases subglacial conduits formed by the ‘cut-and-closure’ mechanism. Investigations of the spatial distribution of such conduits often require a combination of different methods. Here, we studied the englacial drainage system in the cold glacier Longyearbreen, Svalbard by combining speleological exploration of a 478 m long meltwater conduit with a high-resolution ground penetrating radar (GPR) survey with two different centre-frequencies (25 and 100 MHz). The results yielded a 3-D documentation of the present englacial drainage system. The study shows that the overall form of englacial conduits can be detected from velocity−depth converted GPR data, and that the 3-D model can facilitate a method to pinpoint the reflections in a radargram corresponding with the englacial drainage system, although fine detail cannot be resolved. Visible reflections approximately parallel to the mapped englacial water drainage system likely result from sediment incorporated in the ice or from abandoned parts of the englacial drainage system.

scholarly journals Viral dynamics in cryoconite holes on a high Arctic glacier (Svalbard)

2007 ◽  
Vol 112 (G4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Alexandre M. Anesio ◽  
Birgit Mindl ◽  
Johanna Laybourn-Parry ◽  
Andrew J. Hodson ◽  
Birgit Sattler
Keyword(s):  
High Arctic ◽  
Viral Dynamics ◽  
Arctic Glacier

scholarly journals Subglacial drainage processes at a High Arctic polythermal valley glacier

2005 ◽  
Vol 51 (172) ◽  
pp. 15-24 ◽  
Author(s):  
Robert G. Bingham ◽  
Peter W. Nienow ◽  
Martin J. Sharp ◽  
Sarah Boon
Keyword(s):  
Drainage System ◽  
Structural Evolution ◽  
Subsequent Development ◽  
High Arctic ◽  
Breakthrough Curves ◽  
Ice Flow ◽  
Dye Tracer ◽  
Arctic Glacier ◽  
Tracer Experiments ◽  
Subglacial Drainage

AbstractDye-tracer experiments undertaken over two summer melt seasons at polythermal John Evans Glacier, Ellesmere Island, Canada, were designed to investigate the character of the subglacial drainage system and its evolution over a melt season. In both summers, dye injections were conducted at several moulins and traced to a single subglacial outflow. Tracer breakthrough curves suggest that supraglacial meltwater initially encounters a distributed subglacial drainage system in late June. The subsequent development and maintenance of a channelled subglacial network are dependent upon sustained high rates of surface melting maintaining high supraglacial inputs. In a consistently warm summer (2000), subglacial drainage became rapidly and persistently channelled. In a cooler summer (2001), distributed subglacial drainage predominated. These observations confirm that supraglacial meltwater can access the bed of a High Arctic glacier in summer, and induce significant structural evolution of the subglacial drainage system. They do not support the view that subglacial drainage systems beneath polythermal glaciers are always poorly developed. They do suggest that the effects on ice flow of surface water penetration to the bed of predominantly cold glaciers may be short-lived.

scholarly journals An investigation into the mechanisms controlling seasonal speedup events at a High Arctic glacier

2008 ◽  
Vol 113 (F2) ◽  
Author(s):  
Robert G. Bingham ◽  
Alun L. Hubbard ◽  
Peter W. Nienow ◽  
Martin J. Sharp
Keyword(s):  
High Arctic ◽  
Arctic Glacier
Sign in / Sign up

Export Citation Format

Share Document