A Frost Tube for the Determination of Freezing in the Active Layer above Permafrost

1973 ◽  
Vol 10 (3) ◽  
pp. 392-396 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Active Layer ◽  
Vertical Migration ◽  
Water Interface ◽  
Coarse Particles ◽  
Upward Moving ◽  
Ice Water

A frost tube which can be used in permafrost areas to determine both the downward and upward movements of the two freezing fronts in the active layer, during the fall freeze-back period, is described. The principle, which is based upon the differential vertical migration of fine and coarse particles resting upon an upward moving horizontal ice–water interface, is discussed. Attention is drawn to some of the ice characteristics of the active layer and top of the permafrost which result from upward freezing at the bottom of the active layer.

Polarizability and nonpolarizability of oil-water interfaces with relevance to a.c. impendance measurements

1991 ◽  
Vol 56 (1) ◽  
pp. 112-129 ◽  
Author(s):  
Takashi Kakiuchi ◽  
Mitsugi Senda
Keyword(s):  
Charge Transfer ◽  
Numerical Calculation ◽  
Supporting Electrolyte ◽  
Water Interface ◽  
Migration Effect ◽  
Ac Current ◽  
Stationary Interface ◽  
Oil Water ◽  
Anion Transfer

We have estimated the degree of polarizability of a polarized oil-water interface used as a working interface and that of the nonpolarizability of a nonpolarized interface used as a reference oil-water interface from the numerical calculation of dc and ac current vs potential behavior at both interfaces. Theoretical equations of dc and ac currents for simultaneous cation and anion transfer of supporting electrolytes have been derived for the planar stationary interface for reversible and quasi-reversible cases. In the derivation, the migration effect and the coupling of the cation and anion transfer have been incorporated. The transfer of ions constituting a supporting electrolyte contributes to the total admittance of the interface even in the region where the interface may be considered as polarized in dc sense, as pointed out first by Samec et al. (J. Electroanal. Chem. 126, 121 (1981)). Moreover, the reference oil-water interface is not ideally reversible, so that the contribution from this interface to the measured admittance cannot be negligible, unless the area of the reference oil-water interface is much larger than that of the working oil-water interface. The effect of non-ideality of the reference oil-water interface on the determination of double layer capacitances and kinetic parameters of charge transfer at the working oil-water interface has been estimated.

scholarly journals Sea-ice habitat minimizes grazing impact and predation risk for larval Antarctic krill

Polar Biology ◽  
2021 ◽  
Author(s):  
Carmen L. David ◽  
Fokje L. Schaafsma ◽  
Jan A. van Franeker ◽  
Evgeny A. Pakhomov ◽  
Brian P. V. Hunt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Predation Risk ◽  
Water Column ◽  
Antarctic Krill ◽  
Standing Stock ◽  
Euphausia Superba ◽  
Grazing Impact ◽  
Water Interface ◽  
Winter Habitat ◽  
Ice Water

AbstractSurvival of larval Antarctic krill (Euphausia superba) during winter is largely dependent upon the presence of sea ice as it provides an important source of food and shelter. We hypothesized that sea ice provides additional benefits because it hosts fewer competitors and provides reduced predation risk for krill larvae than the water column. To test our hypothesis, zooplankton were sampled in the Weddell-Scotia Confluence Zone at the ice-water interface (0–2 m) and in the water column (0–500 m) during August–October 2013. Grazing by mesozooplankton, expressed as a percentage of the phytoplankton standing stock, was higher in the water column (1.97 ± 1.84%) than at the ice-water interface (0.08 ± 0.09%), due to a high abundance of pelagic copepods. Predation risk by carnivorous macrozooplankton, expressed as a percentage of the mesozooplankton standing stock, was significantly lower at the ice-water interface (0.83 ± 0.57%; main predators amphipods, siphonophores and ctenophores) than in the water column (4.72 ± 5.85%; main predators chaetognaths and medusae). These results emphasize the important role of sea ice as a suitable winter habitat for larval krill with fewer competitors and lower predation risk. These benefits should be taken into account when considering the response of Antarctic krill to projected declines in sea ice. Whether reduced sea-ice algal production may be compensated for by increased water column production remains unclear, but the shelter provided by sea ice would be significantly reduced or disappear, thus increasing the predation risk on krill larvae.

scholarly journals Tank study of physico-chemical controls on gas content and composition during growth of young sea ice

2002 ◽  
Vol 48 (161) ◽  
pp. 177-191 ◽  
Author(s):  
Jean-Louis Tison ◽  
Christian Haas ◽  
Marcia M. Gowing ◽  
Suzanne Sleewaegen ◽  
Alain Bernard
Keyword(s):  
Sea Ice ◽  
Sea Water ◽  
Bubble Nucleation ◽  
Water Dynamics ◽  
Gas Content ◽  
First Year ◽  
Water Interface ◽  
Atmospheric Gases ◽  
Physico Chemical ◽  
Ice Water

AbstractDuring an ice-tank experiment, samples were taken to study the processes of acquisition and alteration of the gas properties in young first-year sea ice during a complete growth–warming–cooling cycle. The goal was to obtain reference levels for total gas content and concentrations of atmospheric gases (O2, N2, CO2) in the absence of significant biological activity. The range of total gas-content values obtained (3.5–18 mL STP kg−1) was similar to previous measurements or estimates. However, major differences occurred between current and quiet basins, showing the role of the water dynamics at the ice–water interface in controlling bubble nucleation processes. Extremely high CO2concentrations were observed in all the experiments (up to 57% in volume parts). It is argued that these could have resulted from two unexpected biases in the experimental settings. Concentrations in bubbles nucleated at the interface are controlled by diffusion both from the ice–water interface towards the well-mixed reservoir and between the interface water and the bubble itself. This double kinetic effect results in a transition of the gas composition in the bubbles from values close to solubility in sea water toward values close to atmospheric, as the ice cover builds up.

scholarly journals Isotopic fractionation during grain coarsening of wet snow

1993 ◽  
Vol 18 ◽  
pp. 129-134 ◽  
Author(s):  
Masayoshi Nakawo ◽  
Shigeru Chiba ◽  
Hiroshi Satake ◽  
Shigeru Kinouchi
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Rapid Change ◽  
Isotopic Fractionation ◽  
Water Interface ◽  
Grain Coarsening ◽  
Isotope Concentration ◽  
Large Particles ◽  
Wet Snow ◽  
Ice Water

Isotopic composition of solid and liquid portions of wet snow was investigated experimentally. The compositions changed with time, δ values of ice becoming heavier than those for water. A simple model was proposed to explain their temporal variation. It predicted, however, a more rapid change of δ values than the trend obtained in the experiments. This suggests the presence of a “diffusion layer” adjacent to growing snow particles, where isotope concentration has dropped at the ice-water interface because of the fractionation during grain coarsening. The slope in δD–δ18O diagram estimated by the model is compatible with the experimental data. It is considered, therefore, that the freezing fraction, the part of the liquid which refreezes to relatively large particles during grain coarsening, could be estimated by measuring the isotope concentration.

In situ structure and force characterization of 2D nano-colloids at the air/water interface

Soft Matter ◽  
2019 ◽  
Vol 15 (42) ◽  
pp. 8475-8482
Author(s):  
Giovanni Li-Destri ◽  
Roberta Ruffino ◽  
Nunzio Tuccitto ◽  
Giovanni Marletta
Keyword(s):  
Quantitative Determination ◽  
Experimental Method ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Interaction Forces ◽  
Air Water Interface

We have developed a novel experimental method, which enables quantitative determination of interaction forces between interfacial nanoparticles as a function of the inter-particle distance at liquid interfaces.

Heightened Cold-Denaturation of Proteins at the Ice–Water Interface

2020 ◽  
Vol 142 (12) ◽  
pp. 5722-5730 ◽  
Author(s):  
Andrea Arsiccio ◽  
James McCarty ◽  
Roberto Pisano ◽  
Joan-Emma Shea
Keyword(s):  
Water Interface ◽  
Cold Denaturation ◽  
Ice Water ◽  
Denaturation Of Proteins
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