604 Dissociation of Methane Hydrate in Okhotsk Sea : Survey of Methane Concentration in Sea Water and Sea Ice

AbstractSixty-three ice cores were collected in the Bellingshausen and Amundsen Seas in August and September 1993 during a cruise of the R.V. Nathaniel B. Palmer. The structure and stable-isotopic composition (18O/16O) of the cores were investigated in order to understand the growth conditions and to identify the key growth processes, particularly the contribution of snow to sea-ice formation. The structure and isotopic composition of a set of 12 cores that was collected for the same purpose in the Bellingshausen Sea in March 1992 are reassessed. Frazil ice and congelation ice contribute 44% and 26%, respectively, to the composition of both the winter and summer ice-core sets, evidence that the relatively calm conditions that favour congelation-ice formation are neither as common nor as prolonged as the more turbulent conditions that favour frazil-ice growth and pancake-ice formation. Both frazil- and congelation-ice layers have an av erage thickness of 0.12 m in winter, evidence that congelation ice and pancake ice thicken primarily by dynamic processes. The thermodynamic development of the ice cover relies heavily on the formation of snow ice at the surface of floes after sea water has flooded the snow cover. Snow-ice layers have a mean thickness of 0.20 and 0.28 m in the winter and summer cores, respectively, and the contribution of snow ice to the winter (24%) and summer (16%) core sets exceeds most quantities that have been reported previously in other Antarctic pack-ice zones. The thickness and quantity of snow ice may be due to a combination of high snow-accumulation rates and snow loads, environmental conditions that favour a warm ice cover in which brine convection between the bottom and top of the ice introduces sea water to the snow/ice interface, and bottom melting losses being compensated by snow-ice formation. Layers of superimposed ice at the top of each of the summer cores make up 4.6% of the ice that was examined and they increase by a factor of 3 the quantity of snow entrained in the ice. The accumulation of superimposed ice is evidence that melting in the snow cover on Antarctic sea-ice floes ran reach an advanced stage and contribute a significant amount of snow to the total ice mass.

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ARCHAEAL ABUNDANCE AND DIVERSITY WITHIN DIFFERENT SECTIONS OF SUMMER SEA-ICE AND SEA WATER IN PRYDZ BAY, ANTARCTICA

CHINESE JOURNAL OF POLAR RESEARCH ◽

10.3724/sp.j.1084.2013.00124 ◽

2014 ◽

Vol 25 (2) ◽

pp. 124-131

Author(s):

Jifei Ma ◽

Zongjun Du ◽

Wei Luo ◽

Yong Yu ◽

Yinxin Zeng ◽

...

Keyword(s):

Sea Ice ◽

Sea Water ◽

Prydz Bay ◽

Abundance And Diversity

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Influence of Okhotsk sea-ice extent on atmospheric circulation

Geophysical Research Letters ◽

10.1029/96gl03474 ◽

1996 ◽

Vol 23 (24) ◽

pp. 3595-3598 ◽

Cited By ~ 33

Author(s):

Meiji Honda ◽

Koji Yamazaki ◽

Yoshihiro Tachibana ◽

Kensuke Takeuchi

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Okhotsk Sea ◽

Sea Ice Extent

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

Journal of Glaciology ◽

10.3189/172756502781831377 ◽

2002 ◽

Vol 48 (161) ◽

pp. 177-191 ◽

Cited By ~ 64

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.

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Phase Relationships in Sea Ice as a Function of Temperature

Journal of Glaciology ◽

10.3189/s0022143000013770 ◽

1976 ◽

Vol 17 (77) ◽

pp. 507-519 ◽

Cited By ~ 8

Author(s):

C. Richardson

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Sea Ice ◽

Sea Water ◽

Tabular Form ◽

Nuclear Magnetic Resonance Spectrometer ◽

Quantitative Measurements ◽

Water Based ◽

Eutectic Concentration ◽

Phase Relationships

Quantitative measurements of the liquid water phase in a sample of sea ice were made with a nuclear magnetic resonance spectrometer. The measurements are used to compute the phase relationships in sea ice as a function of temperature. A model for sea-water based upon a mixture of seven binary salts is used for these computations. The n.m.r. measurements are related to the solvation water which is associated with each binary salt. This solvation water is bound to the salt in a pseudo-crystalline structure, with the amount of water determined by the eutectic concentration of the salt. The results are given in tabular form and differ somewhat from previously published tables. Two controversial hydrated salts were added to the table, based on the n.m.r. data.

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Evidence for significant protein-like dissolved organic matter accumulation in Sea of Okhotsk sea ice

Annals of Glaciology ◽

10.3189/2015aog69a002 ◽

2015 ◽

Vol 56 (69) ◽

pp. 1-8 ◽

Cited By ~ 12

Author(s):

Mats A. Granskog ◽

Daiki Nomura ◽

Susann Müller ◽

Andreas Krell ◽

Takenobu Toyota ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Sea Ice ◽

Surface Waters ◽

Sea Of Okhotsk ◽

Sea Water ◽

First Year ◽

Ice Melt ◽

Ultraviolet Range ◽

Considerable Excess

AbstractAbsorption and fluorescence of chromophoric dissolved organic matter (CDOM) in sea ice and surface waters in the southern Sea of Okhotsk was examined. Sea-water CDOM had featureless absorption increasing exponentially with shorter wavelengths. Sea ice showed distinct absorption peaks in the ultraviolet, especially in younger ice. Older first-year sea ice had relatively flat absorption spectra in the ultraviolet range. Parallel factor analysis (PARAFAC) identified five fluorescent CDOM components, two humic-like and three protein-like. Sea water was largely governed by humic-like fluorescence. In sea ice, protein-like fluorescence was found in considerable excess relative to sea water. The accumulation of protein-like CDOM fluorescence in sea ice is likely a result of biological activity within the ice. Nevertheless, sea ice does not contribute excess CDOM during melt, but the material released will be of different composition than that present in the underlying waters. Thus, at least transiently, the CDOM introduced during sea-ice melt might provide a more labile source of fresher protein-like DOM to surface waters in the southern Sea of Okhotsk.

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Structure and Variability of Bering and Okhotsk Sea-Ice Cover by Satellite Microwave Imagery1

Energy Resources of the Pacific Region ◽

10.1306/st12420c33 ◽

1981 ◽

Author(s):

W. J. Campbell ◽

R. O. Ramseier ◽

H. J. Zwally ◽

P. Gloersen

Keyword(s):

Sea Ice ◽

Ice Cover ◽

Okhotsk Sea ◽

Satellite Microwave

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The Formation and Composition of the Gas Content of Sea Ice

Journal of Glaciology ◽

10.1017/s0022143000014064 ◽

1979 ◽

Vol 22 (86) ◽

pp. 67-81 ◽

Cited By ~ 13

Author(s):

V. L. Tsurikov

Keyword(s):

Sea Ice ◽

Sea Water ◽

Major Effect ◽

Relative Volume ◽

Gas Content ◽

Dominant Factor ◽

Sea Floor ◽

Sea Bottom ◽

Initial Freezing ◽

Air Pockets

Abstract The different factors contributing to the formation of the gas porosity of sea ice are: (Ia) gases captured during the formation of the initial ice cover, (Ib) gases released from solution during the initial freezing of sea-water, (Ic) the inclusion of gases rising from the sea bottom, (2a) the substitution of gas for brine drained from the ice during times of melting, (2b) the release of gas from the brine within the ice during the course of partial freezing, and (2c) the formation of voids filled with water vapour during the course of internal melting. An analysis is made of each of these processes and it is concluded that processes Ib, 2a, and 2C are important. Process Ic may also be a major effect but it is difficult to evaluate until the rate of gas release from the sea floor is better known. The migration of air pockets into the ice from the overlying snow is shown to be a possible but not a significant effect. Available data on the composition of gas in sea ice are reviewed and it is shown to be significantly different from air. Possible causes for these differences are discussed. The porosity of sea ice, i.e. the total relative volume of its gas plus its brine inclusions, is one of the factors strongly affecting its strength, as has been shown by Tsurikov (1947) and by Weeks and Assur (1968). In seas with high salinities the effect of the presence of brine within the ice will usually be the dominant factor. However on water bodies with low salinities the effect of the gas included within the ice may be greater than the effect of the brine. Despite its significance there have not been any attempts at a quantitative analysis of the entrapment of gas in sea ice. This paper is an attempt at such a study.

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