scholarly journals Bacteria in Himalayan glacial ice and its relationship to dust

2008 ◽  
Vol 5 (6) ◽  
pp. 1741-1750 ◽  
Author(s):  
S. Zhang ◽  
S. Hou ◽  
Y. Wu ◽  
D. Qin
Keyword(s):  
Bacterial Population ◽  
Environmental Changes ◽  
Ice Core ◽  
Community Diversity ◽  
Glacial Ice ◽  
The Core ◽  
Index Analysis ◽  
Weak Negative Correlation ◽  
Two Parameters ◽  
Epifluorescence Microscope

Abstract. Concentrations and community diversity of bacteria from 50 segments of a 108.83 m ice core drilled from the East Rongbuk (ER) Glacier (28.03° N, 86.96° E, 6518 m above sea level) on the northeast slope of Mt. Qomolangma (Everest), covering the period 950–1963 AD, were investigated by epifluorescence microscope, DGGE and Shannon-Weaver index analysis. Bacteria in the ER core were identified as β, γ-proteobacteria and Firmicutes group, with γ-proteobacteria being the dominance. Different bacterial population was identified along the core, reflecting the effects of climatic and environmental changes on the bacterial distribution in the glacial ice. There are four general periods of bacterial diversity, corresponding to four phases of dust abundance revealed by Ca2+ concentrations. However, a previously suggested positive correlation between bacterial and Ca2+ concentrations was not indicated by our observations. Instead, a weak negative correlation was found between these two parameters. Our results suggest that bacterial community diversity, rather than concentrations, might be a suitable biological proxy for the reconstruction of past climatic and environmental changes preserved in glacial ice.

scholarly journals Bacterial diversity in Himalayan glacial ice and its relationship to dust

2008 ◽  
Vol 5 (4) ◽  
pp. 3433-3456 ◽  
Author(s):  
S. Zhang ◽  
S. Hou ◽  
Y. Wu ◽  
D. Qin
Keyword(s):  
Bacterial Community ◽  
Bacterial Diversity ◽  
Environmental Changes ◽  
Ice Core ◽  
Community Diversity ◽  
Glacial Ice ◽  
Bacterial Community Diversity ◽  
Index Analysis ◽  
Two Parameters ◽  
Epifluorescence Microscope

Abstract. Concentrations and community diversity of bacteria from 50 segments of a 108.83 m ice core drilled from the East Rongbuk (ER) Glacier (28.03° N, 86.96° E, 6518 m above sea level) on the northeast slope of Mt. Qomolangma (Everest), covering the period 950–1963 AD, were investigated by epifluorescence microscope, DGGE and Shannon-Weaver index analysis. There are four general periods of bacterial diversity, corresponding to four phases of dust abundance revealed by Ca2+ concentrations. It is indicated that higher bacterial community diversity is associated with warm periods, while lower bacterial community diversity with cold periods. However, a previously suggested positive correlation between bacterial and Ca2+ concentrations was not indicated by our observations. In fact, a weakly negative correlation was found between these two parameters. Our results suggest that bacterial community diversity, rather than concentrations, might be a suitable biological proxy for the reconstruction of past climatic and environmental changes preserved in glacial ice.

scholarly journals Soluble Impurities In Ice Core D-1 Of Dunde Ice Cap, China, Over The Last 500 Years

1990 ◽  
Vol 14 ◽  
pp. 363
Author(s):  
Wu Xiaoling ◽  
Liu Jingsona ◽  
Yang Qinzhou
Keyword(s):  
Atmospheric Chemistry ◽  
Industrial Revolution ◽  
Environmental Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Short Term ◽  
The Core ◽  
Ice Cap ◽  
National Foundation ◽  
Analysis Of Time Series

This paper gives the preliminary results of 26 trace element measurements of ice cores from Dunde Ice Cap, China. The chemical composition of soluble impurities along ice core D-1 covering the last 500 years B P., is reported and interpreted in terms of atmospheric contributions. The dust content in ice cores of Dunde Ice Cap is 36 times higher than in Byrd Station, Antarctica. Variations of soluble elements such as Ca, Mg, Κ and Na, in Dunde Ice cores are very sensitive to climatic and environmental changes. The 25 trace elements in ice core D-1 (K, Na, Ca, Mg, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Al, Sr, Ti, V, Zn, As, Ba, Β, Li, Ρ, S, Sn) were measured. Cationicions arranged in order of content are as follows: Ca > Na > Mg > Κ > Αl > Fe > Ζn > Cu > Μn > Pb > Cr > Ni > Co > Cd etc. The content of soluble impurities has typical terrestrial features. Rock-forming elements such as Ca, Mg, Κ, Na, Si, Al, and Fe make up 99% in the core samples. Particular attention is given to the possible impact of the so-called “pre-Industrial Revolution period” and man’s influence on the atmospheric chemistry. The spectral analysis of time series for the variation of each of the 26 contributions show a 92 year cycle that is present in the variation of all 26 ions with depth. Short-term variations, such as 23, 31, 48, 81 year cycles, are also discussed. The ice-core research program has been supported by the Chinese National Foundation of Natural Science under Grant DO125-4860011.

scholarly journals Soluble Impurities In Ice Core D-1 Of Dunde Ice Cap, China, Over The Last 500 Years

1990 ◽  
Vol 14 ◽  
pp. 363-363
Author(s):  
Wu Xiaoling ◽  
Liu Jingsona ◽  
Yang Qinzhou
Keyword(s):  
Atmospheric Chemistry ◽  
Industrial Revolution ◽  
Environmental Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Short Term ◽  
The Core ◽  
Ice Cap ◽  
National Foundation ◽  
Analysis Of Time Series

This paper gives the preliminary results of 26 trace element measurements of ice cores from Dunde Ice Cap, China. The chemical composition of soluble impurities along ice core D-1 covering the last 500 years B P., is reported and interpreted in terms of atmospheric contributions. The dust content in ice cores of Dunde Ice Cap is 36 times higher than in Byrd Station, Antarctica. Variations of soluble elements such as Ca, Mg, Κ and Na, in Dunde Ice cores are very sensitive to climatic and environmental changes. The 25 trace elements in ice core D-1 (K, Na, Ca, Mg, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Al, Sr, Ti, V, Zn, As, Ba, Β, Li, Ρ, S, Sn) were measured. Cationicions arranged in order of content are as follows: Ca > Na > Mg > Κ > Αl > Fe > Ζn > Cu > Μn > Pb > Cr > Ni > Co > Cd etc. The content of soluble impurities has typical terrestrial features. Rock-forming elements such as Ca, Mg, Κ, Na, Si, Al, and Fe make up 99% in the core samples.Particular attention is given to the possible impact of the so-called “pre-Industrial Revolution period” and man’s influence on the atmospheric chemistry. The spectral analysis of time series for the variation of each of the 26 contributions show a 92 year cycle that is present in the variation of all 26 ions with depth. Short-term variations, such as 23, 31, 48, 81 year cycles, are also discussed. The ice-core research program has been supported by the Chinese National Foundation of Natural Science under Grant DO125-4860011.

scholarly journals Dating of an East Antarctic ice core (GV7) by high resolution chemical stratigraphies

2021 ◽  
Author(s):  
Raffaello Nardin ◽  
Mirko Severi ◽  
Alessandra Amore ◽  
Silvia Becagli ◽  
Francois Burgay ◽  
...  
Keyword(s):  
Environmental Changes ◽  
18Th Century ◽  
Accumulation Rate ◽  
Ice Core ◽  
Methanesulfonic Acid ◽  
Oxygen Isotopic Composition ◽  
Snow Accumulation ◽  
Sea Salt ◽  
The Core ◽  
History Of

Abstract. Ice core dating is the first step for a correct interpretation of climatic and environmental changes. In this work, we release a stratigraphic dating of the uppermost 197 m of the 250 m deep GV7(B) ice core (drilling site, 70°41’S, 158°52’E, 1950 m a.s.l.) with a sub-annual resolution. Chemical stratigraphies of NO3−, MSA (methanesulfonic acid), non-sea salt SO42−, sea-salt ions and the oxygen isotopic composition (δ18O) were used in the annual layer counting upon the identification of a seasonal profile in their records. Different procedures were tested and thanks to the volcanic history of the core, obtained in previous works, an accurate age-depth correlation was obtained for the period 1179–2009 CE. Once the dating of the core was finalized, the annual mean accumulation rate was evaluated throughout the analyzed 197 m of the core, obtaining an annually resolved history of the snow accumulation on site in the last millennium. A small, yet consistent, rise in accumulation rate was found for the last 830 years since the middle of the 18th century.

scholarly journals An ice-core record over the last two centuries from Penny Ice Cap, Baffin Island, Canada

2002 ◽  
Vol 35 ◽  
pp. 29-35 ◽  
Author(s):  
Kumiko Goto-Azuma ◽  
Roy M. Koerner ◽  
David A. Fisher
Keyword(s):  
Environmental Changes ◽  
Ice Core ◽  
Sea Salt ◽  
Ice Age ◽  
Baffin Island ◽  
Ion Chemistry ◽  
Sea Ice Extent ◽  
The Core ◽  
Ice Cap ◽  
Ice Core Record

AbstractIn order to reconstruct climatic and environmental changes in the Canadian Arctic, an 85 m deep ice core drilled in 1995 on Penny Ice Cap, Baffin Island, was analyzed for ions and δ18O. In addition to the core, snow-pit samples collected in 1994 and 1995 were also analyzed. Elution of ions caused by summer melting was observed in the pits. Due to the heavy summer melting on this ice cap, seasonal variations of ion chemistry and δ18O were not always present in the core. Comparisons of this core with a previously reported core drilled 2.5 maway show that the noise contained in single annual time series is 40–50% for ions and 25% for δ18O. the ice-core data, however, provide us with a reasonable proxy record of climatic and environmental changes during the last two centuries on better than a decadal basis. Sulfate and nitrate concentrations started to increase around 1900 and 1960, respectively, due to anthropogenic influx transported from the industrialized regions in North America. Sea-salt concentrations began to increase around the mid-19th century and were elevated throughout the 20th century. This trend of sea-salt concentrations is similar to that of melt percentage, which is a measure of summer temperature. Warming after the Little Ice Age would have reduced the sea-ice extent and led to the elevated sea-salt concentrations on Penny Ice Cap.

Nauwkeurige methode voor de aanwasbepaling van het grondvlak met behulp van de Pressler-boor

1968 ◽  
Vol 12 ◽  
Author(s):  
R. Goossens
Keyword(s):  
Basal Area ◽  
Precise Determination ◽  
Maximum Diameter ◽  
Precise Method ◽  
Maximum Radius ◽  
The Core ◽  
Two Parameters

A precise method for the determination of the increment of the  basal area using the PressIer bore. Refering to  previous research showing that the basal area of the corsica pine could be  characterized by an ellips, we present in this paper a precise method for the  determination of the increment of the basal area. In this method we determine  the direction of the maximum diameter, we measure this diameter and we take a  core in one of the points of tangency of the caliper with the measured tree.  The determination of the diameter perpendicular to the maximum diameter  finishes the work wich is to be done in the forest. From the classical  measurements effectuated on the core and from the measured diameters we can  then determine the form (V) and the excentricity (e). Substituting these two  parameters in the formula 2 or 2', we can also calculate the error of a  radius measured on the core with respect to the representative radius, This  error with them allow us to correct the measured value of the minimum or the  maximum radius and we will be able to do a precise determination of the  increment.

scholarly journals Spatial segregation of mixed-sized counterions in dendritic polyelectrolytes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. S. Kłos ◽  
J. Paturej
Keyword(s):  
Electrostatic Interactions ◽  
Spatial Separation ◽  
Excluded Volume ◽  
The Core ◽  
Bjerrum Length ◽  
Two Component ◽  
Conformational Properties ◽  
Dynamics Simulations ◽  
Two Parameters ◽  
Swelling Factor

AbstractLangevin dynamics simulations are utilized to study the structure of a dendritic polyelectrolyte embedded in two component mixtures comprised of conventional (small) and bulky counterions. We vary two parameters that trigger conformational properties of the dendrimer: the reduced Bjerrum length, $$\lambda _B^*$$ λ B ∗ , which controls the strength of electrostatic interactions and the number fraction of the bulky counterions, $$f_b$$ f b , which impacts on their steric repulsion. We find that the interplay between the electrostatic and the counterion excluded volume interactions affects the swelling behavior of the molecule. As compared to its neutral counterpart, for weak electrostatic couplings the charged dendrimer exists in swollen conformations whose size remains unaffected by $$f_b$$ f b . For intermediate couplings, the absorption of counterions into the pervaded volume of the dendrimer starts to influence its conformation. Here, the swelling factor exhibits a maximum which can be shifted by increasing $$f_b$$ f b . For strong electrostatic couplings the dendrimer deswells correspondingly to $$f_b$$ f b . In this regime a spatial separation of the counterions into core–shell microstructures is observed. The core of the dendrimer cage is preferentially occupied by the conventional ions, whereas its periphery contains the bulky counterions.

scholarly journals Methanesulphonic acid movement in solid ice cores

2004 ◽  
Vol 39 ◽  
pp. 540-544 ◽  
Author(s):  
Barbara T. Smith ◽  
Tas D. Van Ommen ◽  
Mark A. J. Curran
Keyword(s):  
Diffusion Coefficient ◽  
Biological Activity ◽  
Sea Ice ◽  
Diffusion Mechanism ◽  
Ice Core ◽  
Ice Cores ◽  
East Antarctica ◽  
The Core ◽  
Central Value

AbstractMethanesulphonic acid (MSA) is an important trace-ion constituent in ice cores, with connections to biological activity and sea-ice distribution. Post-depositional movement of MSA has been documented in firn, and this study investigates movement in solid ice by measuring variations in MSA distribution across several horizontal sections from an ice core after 14.5 years storage. The core used is from below the bubble close-off depth at Dome Summit South, Law Dome, East Antarctica. MSA concentration was studied at 3 and 0.5 cm resolution across the core widths. Its distribution was uniform through the core centres, but the outer 3 cm showed gradients in concentrations down to less than half of the central value at the core edge. This effect is consistent with diffusion to the surrounding air during its 14.5 year storage. The diffusion coefficient is calculated to be 2 ×10–13 m2 s–1, and the implications for the diffusion mechanism are discussed.

Evidence for a large surface ablation zone in central East Antarctica during the last Ice Age

2003 ◽  
Vol 59 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Martin J. Siegert ◽  
Richard C. A. Hindmarsh ◽  
Gordon S. Hamilton
Keyword(s):  
Ice Core ◽  
Remote Sensing Data ◽  
Ice Age ◽  
Internal Layers ◽  
Ice Flow ◽  
Glacial Ice ◽  
Ice Surface ◽  
Ice Flows ◽  
Last Ice Age ◽  
The Hill

AbstractInternal isochronous ice sheet layers, recorded by airborne ice-penetrating radar, were measured along an ice flowline across a large (>1 km high) subglacial hill in the foreground of the Transantarctic Mountains. The layers, dated through an existing stratigraphic link with the Vostok ice core, converge with the ice surface as ice flows over the hill without noticeable change to their separation with each other or the ice base. A two-dimensional ice flow model that calculates isochrons and particle flowpaths and accounts for ice flow over the hill under steady-state conditions requires net ablation (via sublimation) over the stoss face for the predicted isochrons to match the measured internal layers. Satellite remote sensing data show no sign of exposed ancient ice at this site, however. Given the lack of exposed glacial ice, surface balance conditions must have changed recently from the net ablation that is predicted at this site for the last 85,000 years to accumulation.

scholarly journals Annual layering in the NGRIP ice core during the Eemian

2011 ◽  
Vol 7 (1) ◽  
pp. 749-773 ◽  
Author(s):  
A. Svensson ◽  
M. Bigler ◽  
E. Kettner ◽  
D. Dahl-Jensen ◽  
S. Johnsen ◽  
...  
Keyword(s):  
Boundary Migration ◽  
Ice Core ◽  
Interglacial Period ◽  
Grain Boundary Migration ◽  
Model Estimate ◽  
The Core ◽  
Impurity Analysis ◽  
Annual Layer ◽  
Pressure Melting ◽  
Mis 5E

Abstract. The Greenland NGRIP ice core continuously covers the period from present day back to 123 ka before present, which includes several thousand years of ice from the previous interglacial period, MIS 5e or the Eemian. In the glacial part of the core annual layers can be identified from impurity records and visual stratigraphy, and stratigraphic layer counting has been performed back to 60 ka. In the deepest part of the core, however, the ice is close to the pressure melting point, the visual stratigraphy is dominated by crystal boundaries, and annual layering is not visible to the naked eye. In this study, we apply a newly developed setup for high-resolution ice core impurity analysis to produce continuous records of dust, sodium and ammonium concentrations as well as conductivity of melt water. We analyzed three 2.2 m sections of ice from the Eemian and the glacial inception. In all of the analyzed ice, annual layers can clearly be recognized, most prominently in the dust and conductivity profiles. Part of the samples is, however, contaminated in dust, most likely from drill liquid. It is interesting that the annual layering is preserved despite a very active crystal growth and grain boundary migration in the deep and warm NGRIP ice. Based on annual layer counting of the new records, we determine a mean annual layer thickness close to 11 mm for all three sections, which, to first order, confirms the modeled NGRIP time scale (ss09sea). The counting does, however, suggest a longer duration of the climatically warmest part of the NGRIP record (MIS5e) of up to 1 ka as compared to the model estimate. Our results suggest that stratigraphic layer counting is possible basically throughout the entire NGRIP ice core provided sufficiently highly-resolved profiles become available.

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