Distribution and behavior of ice worms (Mesenchytraeus solifugus) in south-central Alaska

2001 ◽  
Vol 79 (10) ◽  
pp. 1813-1821 ◽  
Author(s):  
Daniel H Shain ◽  
Tarin A Mason ◽  
Angela H Farrell ◽  
Lisa A Michalewicz
Keyword(s):  
Diurnal Cycle ◽  
Visible Spectrum ◽  
Gulf Of Alaska ◽  
Lateral Movement ◽  
Glacier Surface ◽  
Alaska Range ◽  
South Central ◽  
Glacier Ice ◽  
And Behavior

The ice worm, Mesenchytraeus solifugus ssp. rainierensis, is the only known annelid that survives in glacier ice. We report the locations of eight ice worm populations in south-central Alaska, including the northern- and western-most extent of known ice worm habitation. All ice worms identified in this study inhabit coastal glaciers proximal to the Gulf of Alaska. They were found in a variety of habitats including level snowfields, steep avalanche cones, crevasse walls, glacial rivers and pools, and hard glacier ice. Ice worms were not found on all coastal glaciers nor were they found in Alaska's interior (the Alaska Range). Ice worms on Byron Glacier, Alaska, totaled ~30 million and were distributed on seven distinct avalanche cones. They displayed a diurnal cycle, appearing on the glacier surface several hours before sunset and penetrating back into the glacier shortly after sunrise. Experiments suggest that ice worms preferentially penetrate the glacier beneath surface algae, Chlamydomonas nivalis, to a depth between 15 and 100 cm and resurface at a proximal location. Lateral movement of ice worms on the glacier surface can reach speeds of ~3 m/h. Ice worms on Byron Glacier avoided light, but did not respond preferentially to different wavelengths in the visible spectrum. Finally, ice worms displayed an unexpected attraction to heat.

scholarly journals Airborne surface profiling of glaciers: a case-study in Alaska

1996 ◽  
Vol 42 (142) ◽  
pp. 538-547 ◽  
Author(s):  
Κ. A. Echelmeyer ◽  
W. D. Harrison ◽  
C. F. Larsen ◽  
J. Sapiano ◽  
Mitchell J. E. ◽  
...  
Keyword(s):  
Time Intervals ◽  
Glacier Surface ◽  
Alaska Range ◽  
Thickness Change ◽  
Surface Profiling ◽  
Bear Lake ◽  
South Central ◽  
Short Time

AbstractA relatively lightweight and simple airborne system for surface elevation profiling of glaciers in narrow mountain valleys has been developed and tested. The aircraft position is determined by kinematic global positioning system (GPS) methods. The distance to the glacier surface is determined with a laser ranger. The accuracy is about 0.3 m, sufficient to permit future changes to be observed over short time intervals. Long-term changes can be estimated by comparison of profiles with existing maps. Elevation profiles obtained in 1993–94 from three glaciers in central and south-central Alaska are compared with maps made about 1950. The resulting area-averaged, seasonally corrected thickness changes during the interval are: Gulkana Glacier (central Alaska Range)–11 m, Worthington Glacier (central Chugach Mountains) +7 m, and Bear Lake Glacier (Kenai Mountains) −12 m. All three glaciers retreated during the interval of comparison. The estimated uncertainty in the average thickness change is ±5 m. which is mainly due to errors in the existing maps. Constraints on the accuracy of the maps are obtained by profiling in proglacial areas.

scholarly journals Airborne surface profiling of glaciers: a case-study in Alaska

1996 ◽  
Vol 42 (142) ◽  
pp. 538-547 ◽  
Author(s):  
Κ. A. Echelmeyer ◽  
W. D. Harrison ◽  
C. F. Larsen ◽  
J. Sapiano ◽  
Mitchell J. E. ◽  
...  
Keyword(s):  
Time Intervals ◽  
Glacier Surface ◽  
Alaska Range ◽  
Thickness Change ◽  
Surface Profiling ◽  
Bear Lake ◽  
South Central ◽  
Short Time

AbstractA relatively lightweight and simple airborne system for surface elevation profiling of glaciers in narrow mountain valleys has been developed and tested. The aircraft position is determined by kinematic global positioning system (GPS) methods. The distance to the glacier surface is determined with a laser ranger. The accuracy is about 0.3 m, sufficient to permit future changes to be observed over short time intervals. Long-term changes can be estimated by comparison of profiles with existing maps. Elevation profiles obtained in 1993–94 from three glaciers in central and south-central Alaska are compared with maps made about 1950. The resulting area-averaged, seasonally corrected thickness changes during the interval are: Gulkana Glacier (central Alaska Range)–11 m, Worthington Glacier (central Chugach Mountains) +7 m, and Bear Lake Glacier (Kenai Mountains) −12 m. All three glaciers retreated during the interval of comparison. The estimated uncertainty in the average thickness change is ±5 m. which is mainly due to errors in the existing maps. Constraints on the accuracy of the maps are obtained by profiling in proglacial areas.

scholarly journals Melt regimes, stratigraphy, flow dynamics and glaciochemistry of three glaciers in the Alaska Range

2012 ◽  
Vol 58 (207) ◽  
pp. 99-109 ◽  
Author(s):  
Seth Campbell ◽  
Karl Kreutz ◽  
Erich Osterberg ◽  
Steven Arcone ◽  
Cameron Wake ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Ice Core ◽  
Chemical Diffusion ◽  
Flow Dynamics ◽  
Alaska Range ◽  
Ice Volume ◽  
Glacier Ice ◽  
Age Model ◽  
Ground Penetrating ◽  
Climate Studies

AbstractWe used ground-penetrating radar (GPR), GPS and glaciochemistry to evaluate melt regimes and ice depths, important variables for mass-balance and ice-volume studies, of Upper Yentna Glacier, Upper Kahiltna Glacier and the Mount Hunter ice divide, Alaska. We show the wet, percolation and dry snow zones located below ~2700ma.s.l., at ~2700 to 3900ma.s.l. and above 3900ma.s.l., respectively. We successfully imaged glacier ice depths upwards of 480 m using 40-100 MHz GPR frequencies. This depth is nearly double previous depth measurements reached using mid-frequency GPR systems on temperate glaciers. Few Holocene-length climate records are available in Alaska, hence we also assess stratigraphy and flow dynamics at each study site as a potential ice-core location. Ice layers in shallow firn cores and attenuated glaciochemical signals or lacking strata in GPR profiles collected on Upper Yentna Glacier suggest that regions below 2800ma.s.l. are inappropriate for paleoclimate studies because of chemical diffusion, through melt. Flow complexities on Kahiltna Glacier preclude ice-core climate studies. Minimal signs of melt or deformation, and depth-age model estimates suggesting ~4815 years of ice on the Mount Hunter ice divide (3912ma.s.l.) make it a suitable Holocene-age ice-core location.

scholarly journals Reconstruction of recent climate change in Alaska from the Aurora Peak ice core, central Alaska

2015 ◽  
Vol 11 (2) ◽  
pp. 217-226 ◽  
Author(s):  
A. Tsushima ◽  
S. Matoba ◽  
T. Shiraiwa ◽  
S. Okamoto ◽  
H. Sasaki ◽  
...  
Keyword(s):  
Climate Change ◽  
Accumulation Rate ◽  
Ice Core ◽  
Chemical Species ◽  
Volcanic Eruptions ◽  
Gulf Of Alaska ◽  
Temporal Variations ◽  
Storm Activity ◽  
Alaska Range ◽  
Recent Climate

Abstract. A 180.17 m ice core was drilled at Aurora Peak in the central part of the Alaska Range, Alaska, in 2008 to allow reconstruction of centennial-scale climate change in the northern North Pacific. The 10 m depth temperature in the borehole was −2.2 °C, which corresponded to the annual mean air temperature at the drilling site. In this ice core, there were many melt–refreeze layers due to high temperature and/or strong insolation during summer seasons. We analyzed stable hydrogen isotopes (δD) and chemical species in the ice core. The ice core age was determined by annual counts of δD and seasonal cycles of Na+, and we used reference horizons of tritium peaks in 1963 and 1964, major volcanic eruptions of Mount Spurr in 1992 and Mount Katmai in 1912, and a large forest fire in 2004 as age controls. Here, we show that the chronology of the Aurora Peak ice core from 95.61 m to the top corresponds to the period from 1900 to the summer season of 2008, with a dating error of ± 3 years. We estimated that the mean accumulation rate from 1997 to 2007 (except for 2004) was 2.04 m w.eq. yr-1. Our results suggest that temporal variations in δD and annual accumulation rates are strongly related to shifts in the Pacific Decadal Oscillation index (PDOI). The remarkable increase in annual precipitation since the 1970s has likely been the result of enhanced storm activity associated with shifts in the PDOI during winter in the Gulf of Alaska.

scholarly journals The determination of glacier speed by time-lapse photography under unfavorable conditions

1992 ◽  
Vol 38 (129) ◽  
pp. 257-265 ◽  
Author(s):  
W.D. Harrison ◽  
K.A. Echelmeyer ◽  
D.M. Cosgrove ◽  
C. F. Raymond
Keyword(s):  
Time Lapse ◽  
Systematic Errors ◽  
Horizontal Motion ◽  
Limited Information ◽  
Glacier Surface ◽  
Alaska Range ◽  
Use Of Time ◽  
West Fork ◽  
Time Lapse Photography

AbstractTwo practical problems in the use of time-lapse photography for the measurement of speed were encountered during the recent surge of West Fork Glacier in the central Alaska Range, Alaska, U.S.A. The first is severe rotational camera instability; we show how natural, unsurveyed features on the valley wall can be used to make the necessary corrections. The second problem is the computation of absolute speed when many different, unsurveyed glacier-surface features are used as targets. We give a method for connecting the data obtained from different targets, and for determining the scale using limited information obtained by surveying. Severe systematic errors can occur unless the angle between the axis of the lens and the direction of horizontal motion is determined.

scholarly journals Effects of the 1966–68 Eruptions of Mount Redoubt on the Flow of Drift Glacier, Alaska, U.S.A.

1986 ◽  
Vol 32 (112) ◽  
pp. 355-362 ◽  
Author(s):  
Matthew Sturm ◽  
Carl Benson ◽  
Peter MacKeith
Keyword(s):  
Equilibrium Condition ◽  
Summit Crater ◽  
Kinematic Wave ◽  
Cook Inlet ◽  
Glacier Surface ◽  
Eruptive Cycle ◽  
Glacier Ice ◽  
Order Of Magnitude

AbstractMount Redoubt, a volcano located west of Cook Inlet in Alaska, erupted from 1966 to 1968. This eruptive cycle removed about 6 × 107m3of glacier ice from the upper part of Drift Glacier and decoupled it from the lower part during a sequence of jökulhlaups which originated in the Summit Crater and flooded Drift River. The same events blanketed the lower part of the glacier with sand and ash, reducing ice ablation. Normal snowfall, augmented by intense avalanching, regenerated the upper part of the glacier by 1976, 8 years after the eruptions. When the regenerated glacier connected with the rest of Drift Glacier, it triggered a kinematic wave of thickening ice accompanied by accelerating surface velocities in the lower part of the glacier. Surface velocities increased by an order of magnitude and were accompanied by thickening of 70 m or more. At the same time, parts of the upper glacier thinned 70 m. The glacier appears to be returning to its pre-eruption equilibrium condition.

scholarly journals Some Observations on the Behavior of the Liquid and Gas Phases in Temperate Glacier Ice

1975 ◽  
Vol 14 (71) ◽  
pp. 213-233 ◽  
Author(s):  
C. F. Raymond ◽  
W. D. Harrison
Keyword(s):  
Large Scale ◽  
Water Flux ◽  
Coarse Grained ◽  
Glacier Surface ◽  
Cross Sectional ◽  
Gas Phases ◽  
Upper Limit ◽  
Melt Water ◽  
Glacier Ice ◽  
Typical Summer

Microscopic and textural observations were made on ice samples cored from Blue Glacier slightly below the equilibrium line to depths of 60 m. Observations were started within a few minutes after collection Water was found in veins along three-grain intersections, in lenses on grain boundaries and in irregular shapes. Gas was found in bubbles in the interior of crystals, in bubbles touching veins and locally in veins Vein sizes showed some spread; average cross-sectional area was about 74 × 10−4mm2with no discernible, trend with texture or depth except within 7 m of the surface. Before the samples were examined they could have experienced a complex relaxation which could have changed them significantly As a result it is not possible to determine thein situsize of veins, but an upper limit can be determined. Also it is not possible to predict intergranular water flux per unit area, but 1 × 10−1m a−1represents an upper limit. In coarse-grained ice the water flux density is likely to be even smaller, because of a low density of veins and blocking by bubbles. This indicates that only a very small fraction of the melt-water production on a typical summer day can penetrate into the glacier on an intergranular scale except possibly near the surface. The existence of conduit-like features in several cores suggests that much melt water ran nevertheless penetrate the ice locally without large-scale lateral movements along the glacier surface. The observed profile of ice temperature indicates that the intergranular water flux may be much smaller than the upper limit determined from the core samples.

scholarly journals Some Observations on the Behavior of the Liquid and Gas Phases in Temperate Glacier Ice

1975 ◽  
Vol 14 (71) ◽  
pp. 213-233 ◽  
Author(s):  
C. F. Raymond ◽  
W. D. Harrison
Keyword(s):  
Large Scale ◽  
Water Flux ◽  
Coarse Grained ◽  
Glacier Surface ◽  
Cross Sectional ◽  
Gas Phases ◽  
Upper Limit ◽  
Melt Water ◽  
Glacier Ice ◽  
Typical Summer

Microscopic and textural observations were made on ice samples cored from Blue Glacier slightly below the equilibrium line to depths of 60 m. Observations were started within a few minutes after collection. Water was found in veins along three-grain intersections, in lenses on grain boundaries and in irregular shapes. Gas was found in bubbles in the interior of crystals, in bubbles touching veins, and locally in veins. Vein sizes showed some spread; average cross-sectional area was about 7 × 10−4 mm2 with no discernible, trend with texture or depth except within 7 m of the surface. Before the samples were examined they could have experienced a complex relaxation which could have changed them significantly. As a result it is not possible to determine the in situ size of veins, but an upper limit can be determined. Also it is not possible to predict intergranular water flux per unit area, but 1 × 10−1 m a−1 represents an upper limit. In coarse-grained ice the water flux density is likely to be even smaller, because of a low density of veins, and blocking by bubbles. This indicates that only a very small fraction of the melt-water production on a typical summer day can penetrate into the glacier on an intergranular scale except possibly near the surface. The existence of conduit-like features in several cores suggests that much melt water can nevertheless penetrate the ice locally without large-scale lateral movements along the glacier surface. The observed profile of ice temperature indicates that the intergranular water flux may be much smaller than the upper limit determined from the core samples.

scholarly journals Effects of the 1966–68 Eruptions of Mount Redoubt on the Flow of Drift Glacier, Alaska, U.S.A.

1986 ◽  
Vol 32 (112) ◽  
pp. 355-362
Author(s):  
Matthew Sturm ◽  
Carl Benson ◽  
Peter MacKeith
Keyword(s):  
Equilibrium Condition ◽  
Summit Crater ◽  
Kinematic Wave ◽  
Cook Inlet ◽  
Glacier Surface ◽  
Eruptive Cycle ◽  
Glacier Ice ◽  
Order Of Magnitude

AbstractMount Redoubt, a volcano located west of Cook Inlet in Alaska, erupted from 1966 to 1968. This eruptive cycle removed about 6 × 107 m3 of glacier ice from the upper part of Drift Glacier and decoupled it from the lower part during a sequence of jökulhlaups which originated in the Summit Crater and flooded Drift River. The same events blanketed the lower part of the glacier with sand and ash, reducing ice ablation. Normal snowfall, augmented by intense avalanching, regenerated the upper part of the glacier by 1976, 8 years after the eruptions. When the regenerated glacier connected with the rest of Drift Glacier, it triggered a kinematic wave of thickening ice accompanied by accelerating surface velocities in the lower part of the glacier. Surface velocities increased by an order of magnitude and were accompanied by thickening of 70 m or more. At the same time, parts of the upper glacier thinned 70 m. The glacier appears to be returning to its pre-eruption equilibrium condition.

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