Chemical analysis of sea ice vein μ-environments using Raman spectroscopy

ABSTRACTSea ice is a unique environment providing a vast habitat for a variety of life, including microscopic organisms. It accounts for roughly 5–6% of the surface area of the oceans. It is a complex porous structure of crystalline water, gas bubbles, and pockets of brine, as well as a connected structure composed of macro- and micro-porosity filled with concentrated aqueous liquids. Using micro-Raman spectroscopy, it is possible to characterise features of ice at a spatial resolution of a few to tens of micrometers, the scale of relevance to trapped microorganisms, by providing information concerning the presence and amount of molecular species present in the trapped liquids. We have applied this technique to determine the spatial distribution of sulphate, phosphate and carbonate anions in sea-ice veins using ice obtained from the vicinity of the Palmer Station, Antarctica. The observed sulphate concentrations were approximately 20–30% higher than nominal surface seawater concentrations, consistent with the concentration of brine in vein and inclusion liquids during the ice formation process. This concentration was lower than that in veins present in laboratory-prepared ice. Carbonate and dibasic phosphate anions were also observed in the sea ice. This speciation is consistent with an alkaline environment in the sea-ice aqueous system. The mean dibasic phosphate concentration found throughout the sample was 648 mM, while, for carbonate, it was 485 mM. However, these anions showed extremely high spatial variability. The high phosphate and carbonate enhancements observed relative to sulphate point to the influence of processes other than brine formation controlling the chemistry of these anions in sea ice.

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Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica

Journal of Glaciology ◽

10.3189/s0022143000002902 ◽

1997 ◽

Vol 43 (143) ◽

pp. 138-151 ◽

Cited By ~ 2

Author(s):

M. O. Jeffries ◽

K. Morris ◽

W.F. Weeks ◽

A. P. Worby

Keyword(s):

Sea Ice ◽

Isotopic Composition ◽

Snow Cover ◽

Sea Water ◽

Ice Cores ◽

Ice Cover ◽

Snow Accumulation ◽

Ice Formation ◽

Frazil Ice ◽

Core Sets

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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First record of the occurrence of sea ice in the Cordillera Darwin fjords (54°S), Chile

Annals of Glaciology ◽

10.1017/aog.2021.3 ◽

2021 ◽

pp. 1-11

Author(s):

Charles Salame ◽

Inti Gonzalez ◽

Rodrigo Gomez-Fell ◽

Ricardo Jaña ◽

Jorge Arigony-Neto

Keyword(s):

Time Series ◽

Sea Ice ◽

First Record ◽

Ice Formation ◽

Future Research ◽

Landsat 8 ◽

Surface Salinity ◽

Air Temperatures ◽

Aerial Reconnaissance ◽

High Precipitation

Abstract This paper provides the first evidence for sea-ice formation in the Cordillera Darwin (CD) fjords in southern Chile, which is farther north than sea ice has previously been reported for the Southern Hemisphere. Initially observed from a passenger plane in September 2015, the presence of sea ice was then confirmed by aerial reconnaissance and subsequently identified in satellite imagery. A time series of Sentinel-1 and Landsat-8 images during austral winter 2015 was used to examine the chronology of sea-ice formation in the Cuevas fjord. A longer time series of imagery across the CD was analyzed from 2000 to 2017 and revealed that sea ice had formed in each of the 13 fjords during at least one winter and was present in some fjords during a majority of the years. Sea ice is more common in the northern end of the CD, compared to the south where sea ice is not typically present. Is suggested that surface freshening from melting glaciers and high precipitation reduces surface salinity and promotes sea-ice formation within the semi-enclosed fjord system during prolonged periods of cold air temperatures. This is a unique set of initial observations that identify questions for future research in this remote area.

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Preparation and Characterization of Carbon Supported Nano-Nickel and its Sorption Behavior for Zinc from Aqueous Solutions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.510-511.271 ◽

2012 ◽

Vol 510-511 ◽

pp. 271-276 ◽

Cited By ~ 1

Author(s):

Tayyaba Asim ◽

R. Ahmed ◽

M.S. Ansari

Keyword(s):

Morphological Study ◽

Aqueous System ◽

Effect Of Temperature ◽

Vacuum Drying ◽

Sorption Behavior ◽

Nickel Deposition ◽

Adsorption Data ◽

Nano Nickel ◽

The Mean

Nickel deposited on carbon has been used as adsorbent to recover Zn (II) from aqueous system. The adsorbent was synthesized by depositing nickel nitrate on carbon under inert conditions and decomposing it to nickel by raising the temperature, washing and vacuum drying. Various techniques including XRD, FTIR, and SEM were employed for its characterization. FTIR showed that the nickel deposition enhanced the carbon functionalization due to presence of OH, C=O and C-O groups.Average crystallite size ofabout 9 nm was determined from XRD. Nickel deposition resulted in further division particles as indicated from the morphological study. Zn (II) was subjected to adsorptionon the synthesized adsorbent. It was observed that the rate of adsorption increased significantly on the nickel deposited carbon than the carbon alone. Morris-Weber, Lagergren and Reichenberg models were applied to find out the type and rate of adsorption employingfirst and second order rate equations.The adsorption data were applied toLangmuir, Freundlich and D-R isotherms and values of isotherm constants were calculated and were higher for Ni/C than carbon alone. The mean free energy of zinc sorption on carbon and Ni/C are 16.67 and 18.26 kJmol-1 which shows chemisorption. Thermodynamic studies were done to find out the effect of temperature on sorption. Positive values of ΔH and negative values of ΔG show endothermic and spontaneous type of sorption.

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Variation in phytoplankton standing stock, chemical composition and physiology during sea-ice formation in the southeastern Weddell Sea, Antarctica

Journal of Experimental Marine Biology and Ecology ◽

10.1016/0022-0981(93)90054-r ◽

1993 ◽

Vol 173 (2) ◽

pp. 211-230 ◽

Cited By ~ 43

Author(s):

Markus Gleitz ◽

David N. Thomas

Keyword(s):

Chemical Composition ◽

Sea Ice ◽

Standing Stock ◽

Weddell Sea ◽

Ice Formation

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Comparison of variations in sea-ice formation in the Weddell Sea with seasonal bottom-water outflow data

1995 International Geoscience and Remote Sensing Symposium, IGARSS '95. Quantitative Remote Sensing for Science and Applications ◽

10.1109/igarss.1995.520292 ◽

2002 ◽

Cited By ~ 2

Author(s):

M.R. Drinkwater ◽

D. Long ◽

D. Early

Keyword(s):

Sea Ice ◽

Bottom Water ◽

Weddell Sea ◽

Ice Formation ◽

Water Outflow

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Thermodynamics of slush and snow–ice formation in the Antarctic sea-ice zone

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2016.03.008 ◽

2016 ◽

Vol 131 ◽

pp. 75-83 ◽

Cited By ~ 7

Author(s):

Mathilde Jutras ◽

Martin Vancoppenolle ◽

Antonio Lourenço ◽

Frédéric Vivier ◽

Gauthier Carnat ◽

...

Keyword(s):

Sea Ice ◽

Ice Formation ◽

Antarctic Sea Ice ◽

The Antarctic

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A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica

The Cryosphere ◽

10.5194/tc-11-343-2017 ◽

2017 ◽

Vol 11 (1) ◽

pp. 343-362 ◽

Cited By ~ 11

Author(s):

Sentia Goursaud ◽

Valérie Masson-Delmotte ◽

Vincent Favier ◽

Susanne Preunkert ◽

Michel Fily ◽

...

Keyword(s):

High Resolution ◽

Sea Ice ◽

Interannual Variability ◽

Ice Core ◽

Ice Sheet ◽

Sea Ice Extent ◽

Antarctic Ice Sheet ◽

Ice Core Record ◽

Decadal Variations ◽

The Mean

Abstract. A 22.4 m-long shallow firn core was extracted during the 2006/2007 field season from coastal Adélie Land. Annual layer counting based on subannual analyses of δ18O and major chemical components was combined with 5 reference years associated with nuclear tests and non-retreat of summer sea ice to build the initial ice-core chronology (1946–2006), stressing uncertain counting for 8 years. We focus here on the resulting δ18O and accumulation records. With an average value of 21.8 ± 6.9 cm w.e. yr−1, local accumulation shows multi-decadal variations peaking in the 1980s, but no long-term trend. Similar results are obtained for δ18O, also characterised by a remarkably low and variable amplitude of the seasonal cycle. The ice-core records are compared with regional records of temperature, stake area accumulation measurements and variations in sea-ice extent, and outputs from two models nudged to ERA (European Reanalysis) atmospheric reanalyses: the high-resolution atmospheric general circulation model (AGCM), including stable water isotopes ECHAM5-wiso (European Centre Hamburg model), and the regional atmospheric model Modèle Atmosphérique Régional (AR). A significant linear correlation is identified between decadal variations in δ18O and regional temperature. No significant relationship appears with regional sea-ice extent. A weak and significant correlation appears with Dumont d'Urville wind speed, increasing after 1979. The model-data comparison highlights the inadequacy of ECHAM5-wiso simulations prior to 1979, possibly due to the lack of data assimilation to constrain atmospheric reanalyses. Systematic biases are identified in the ECHAM5-wiso simulation, such as an overestimation of the mean accumulation rate and its interannual variability, a strong cold bias and an underestimation of the mean δ18O value and its interannual variability. As a result, relationships between simulated δ18O and temperature are weaker than observed. Such systematic precipitation and temperature biases are not displayed by MAR, suggesting that the model resolution plays a key role along the Antarctic ice sheet coastal topography. Interannual variations in ECHAM5-wiso temperature and precipitation accurately capture signals from meteorological data and stake observations and are used to refine the initial ice-core chronology within 2 years. After this adjustment, remarkable positive (negative) δ18O anomalies are identified in the ice-core record and the ECHAM5-wiso simulation in 1986 and 2002 (1998–1999), respectively. Despite uncertainties associated with post-deposition processes and signal-to-noise issues, in one single coastal ice-core record, we conclude that the S1C1 core can correctly capture major annual anomalies in δ18O as well as multi-decadal variations. These findings highlight the importance of improving the network of coastal high-resolution ice-core records, and stress the skills and limitations of atmospheric models for accumulation and δ18O in coastal Antarctic areas. This is particularly important for the overall East Antarctic ice sheet mass balance.

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