scholarly journals Physical processes behind interactions of microplastic particles with natural ice

2022 ◽  
Author(s):  
Irina P Chubarenko
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Cores ◽  
Natural Environments ◽  
Polar Regions ◽  
Air Bubbles ◽  
Field Observations ◽  
Physical Processes ◽  
Ice Surface ◽  
Brittle Ductile Transition

Abstract Microplastic particles (MPs, <5 mm) are found in marine ice in larger quantities than in seawater, however, the distribution pattern within the ice cores is not consistent. To get insights into the most general physical processes behind interactions of ice and plastic particles in cool natural environments, information from academic and applied research is integrated and verified against available field observations. Non-polar molecules of common-market plastics are hydrophobic, so MPs are weak ice nucleators, are repelled from water and ice, and concentrate within air bubbles and brine channels. A large difference in thermal properties of ice and plastics favours concentration of MPs at the ice surface during freeze/thaw cycles. Under low environmental temperatures, falling in polar regions below the glass / brittle-ductile transition temperatures of the common-use plastics, they become brittle. This might partially explain the absence of floating macroplastics in polar waters. Freshwater freezes at the temperature well below that of its maximum density, so the water column is stably stratified, and MPs eventually concentrate at the ice surface and in air bubbles. In contrast, below growing sea ice, mechanisms of suspension freezing under conditions of (thermal plus haline) convection should permanently entangle MPs into ice. During further sea ice growth and aging, MPs are repelled from water and ice into air bubbles, brine channels, and to the upper/lower boundaries of the ice column. Sea ice permeability, especially while melting periods, can re-distribute sub-millimeter MPs through the brine channels, thus potentially introducing the variability of contamination with time. In accord with field observations, analysis reveals several competing factors that influence the distribution of MPs in sea ice. A thorough sampling of the upper ice surface, prevention of brine leakage while sampling and handling, considering the ice structure while segmenting the ice core – these steps may be advantageous for further understanding the pattern of plastic contamination in natural ice.

scholarly journals Basic Properties of Antarctic Sea Ice as Revealed by Textural Analysis of Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 95-101 ◽  
Author(s):  
Manfred A. Lange
Keyword(s):  
Sea Ice ◽  
Coastal Waters ◽  
Ice Core ◽  
Ice Cores ◽  
Biological Properties ◽  
Weddell Sea ◽  
Polar Regions ◽  
Thin Sections ◽  
Antarctic Sea Ice ◽  
Physical Chemical

Sea ice constitutes a major element in the atmospheric, oceanographic and biological regime of the polar regions. Assessment of its fundamental properties requires interdisciplinary investigations on local, regional and global scales. Sea-ice structure and textural parameters of individual ice cores play a key role in such investigations. A proper characterization of sea-ice micro-structure is essential for an adequate classification of ice cores, an understanding of the growth processes of the sampled floe, and the identification of possible relationships between ice texture, and the physical, chemical and biological properties of sea ice. Investigations on ice cores which were obtained during three recent Antarctic expeditions (1983–85) in coastal waters of the eastern and southern Weddell Sea are reported. The basis for a number of physical, chemical and biological investigations is an assessment of the textural characteristics of each sea-ice core. These are derived by inspection of continuous thick sections, supplemented by an analysis of selected vertical and horizontal thin sections. Major results of this study can be summarized as follows: (i) in addition to the common ice classes, another sea-ice type, platelet ice, is identified; it is apparently unique to the coastal waters of Antarctica, near the ice-shelf edge, and (ii) different physical, chemical and biological sea-ice properties vary systematically with and are probably related to / controlled by the ice texture of the cores.

scholarly journals Basic Properties of Antarctic Sea Ice as Revealed by Textural Analysis of Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 95-101 ◽  
Author(s):  
Manfred A. Lange
Keyword(s):  
Sea Ice ◽  
Coastal Waters ◽  
Ice Core ◽  
Ice Cores ◽  
Biological Properties ◽  
Weddell Sea ◽  
Polar Regions ◽  
Thin Sections ◽  
Antarctic Sea Ice ◽  
Physical Chemical

Sea ice constitutes a major element in the atmospheric, oceanographic and biological regime of the polar regions. Assessment of its fundamental properties requires interdisciplinary investigations on local, regional and global scales. Sea-ice structure and textural parameters of individual ice cores play a key role in such investigations. A proper characterization of sea-ice micro-structure is essential for an adequate classification of ice cores, an understanding of the growth processes of the sampled floe, and the identification of possible relationships between ice texture, and the physical, chemical and biological properties of sea ice. Investigations on ice cores which were obtained during three recent Antarctic expeditions (1983–85) in coastal waters of the eastern and southern Weddell Sea are reported. The basis for a number of physical, chemical and biological investigations is an assessment of the textural characteristics of each sea-ice core. These are derived by inspection of continuous thick sections, supplemented by an analysis of selected vertical and horizontal thin sections. Major results of this study can be summarized as follows: (i) in addition to the common ice classes, another sea-ice type, platelet ice, is identified; it is apparently unique to the coastal waters of Antarctica, near the ice-shelf edge, and (ii) different physical, chemical and biological sea-ice properties vary systematically with and are probably related to / controlled by the ice texture of the cores.

scholarly journals Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period

2019 ◽  
Vol 116 (10) ◽  
pp. 4099-4104 ◽  
Author(s):  
Louise C. Sime ◽  
Peter O. Hopcroft ◽  
Rachael H. Rhodes
Keyword(s):  
Sea Ice ◽  
Temperature Increase ◽  
General Circulation ◽  
Ice Core ◽  
Circulation Model ◽  
Ice Cores ◽  
Nitrogen Isotope ◽  
Ice Shelf ◽  
Last Glacial Period ◽  
Precipitation Seasonality

Greenland ice cores provide excellent evidence of past abrupt climate changes. However, there is no universally accepted theory of how and why these Dansgaard–Oeschger (DO) events occur. Several mechanisms have been proposed to explain DO events, including sea ice, ice shelf buildup, ice sheets, atmospheric circulation, and meltwater changes. DO event temperature reconstructions depend on the stable water isotope (δ18O) and nitrogen isotope measurements from Greenland ice cores: interpretation of these measurements holds the key to understanding the nature of DO events. Here, we demonstrate the primary importance of sea ice as a control on Greenland ice coreδ18O: 95% of the variability inδ18O in southern Greenland is explained by DO event sea ice changes. Our suite of DO events, simulated using a general circulation model, accurately captures the amplitude ofδ18O enrichment during the abrupt DO event onsets. Simulated geographical variability is broadly consistent with available ice core evidence. We find an hitherto unknown sensitivity of theδ18O paleothermometer to the magnitude of DO event temperature increase: the change inδ18O per Kelvin temperature increase reduces with DO event amplitude. We show that this effect is controlled by precipitation seasonality.

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.

Seasonal evolution and salt/freshwater fluxes of first-year sea ice: Comparison between pack ice and landfast sea ice 

2021 ◽  
Author(s):  
Marc Oggier ◽  
Hajo Eicken ◽  
Robert Rember ◽  
Allison Fong ◽  
Dmitry V. Divine ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Upper Ocean ◽  
First Year ◽  
Ice Melt ◽  
Ice Surface ◽  
Freshwater Fluxes ◽  
Exchange Processes ◽  
Bulk Salinity ◽  
Landfast Sea Ice

&lt;p&gt;Sea ice affects the exchange of energy and matter between the atmosphere and the ocean from local to hemispheric scales. Salt fluxes across the ice-ocean interface that drive thermohaline mixing beneath growing sea ice are important elements of upper ocean nutrient and carbon exchange. Sea-ice melt releases freshwater into the upper ocean and results in formation of melt ponds that affect gas and energy transfer across the atmosphere-ice interface. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) provided an opportunity to follow sea-ice evolution and exchange processes over a full seasonal cycle in a rapidly changing ice cover. To this end, approximately 25 sea-ice cores were collected at 2 distinct sites, representing first-year and multi-year ice, to monitor physical, biological and geochemical processes relevant to atmosphere-ice-ocean exchange processes. Here we compare the growth and decay of first-year ice in the Central Arctic during the winter 2019-2020 to that of landfast first-year ice at Utqia&amp;#289;vik, Alaska, from 1998 to 2016. Ice stratigraphy was similar at both sites with about 15 cm of granular ice on top of columnar ice, with a comparable growth history with a similar maximum ice thickness of 1.6-1.7 m. We aggregated the sea-ice bulk salinity and temperature profiles using a degree-day approach, and examined brine and freshwater fluxes at lower and upper interfaces of the ice, respectively. Preliminary results show lower sea-ice bulk salinity during the growth season and greater desalination at the ice surface during the melt season at the MOSAiC floe in comparison to Utqia&amp;#289;vik.&lt;/p&gt;

Collocated OLCI optical imagery and SAR radar altimetry from Sentinel3 for enhanced sea ice surface classification

2021 ◽  
Author(s):  
Dorsa Nasrollahi Shirazi ◽  
Michel Tsamados ◽  
Isobel Lawrence ◽  
Sanggyun Lee ◽  
Thomas Johnson ◽  
...  
Keyword(s):  
Sea Ice ◽  
Classification Algorithms ◽  
Polar Regions ◽  
Radar Altimetry ◽  
Imaging Spectrometer ◽  
Ice Surface ◽  
Ice Roughness ◽  
Elevation Data ◽  
Optical Imagery ◽  
Surface Classification

&lt;p&gt;The Copernicus operational Sentinel-3A since February 2016 and Sentinel-3B since April 2018 build on the CryoSat-2 legacy in terms of their synthetic aperture radar (SAR) mode altimetry providing high-resolution radar freeboard elevation data over the polar regions up to 81N. This technology combined with the Ocean and Land Colour Instrument (OLCI) imaging spectrometer offers the first space-time collocated optical imagery and radar altimetry dataset. We use these joint datasets for validation of several existing surface classification algorithms based on Sentinel-3 altimeter echo shapes. We also explore the potential for novel AI techniques such as convolutional neural networks (CNN) for winter and summer sea ice surface classification (i.e. melt pond fraction, lead fraction, sea ice roughness). For lead surface classification we analyse the winters of 2018/19 and 2019/20 and for summer sea ice feature classification we focus on the Sentinel-3A &amp;3B tandem phase of the summer 2018. We compare our CNN models with other existing surface classification algorithms.&lt;/p&gt;

scholarly journals Glaciological Investigations of the Tropical Quelccaya Ice Cap, Peru

1980 ◽  
Vol 25 (91) ◽  
pp. 69-84 ◽  
Author(s):  
Lonnie G. Thompson
Keyword(s):  
Rainy Season ◽  
Ice Core ◽  
Ice Cores ◽  
Dry Season ◽  
Radioactive Material ◽  
Polar Regions ◽  
Near Surface ◽  
Ice Cap ◽  
Activity Measurements ◽  
Quelccaya Ice Cap

AbstractGlaciological results of the continuing investigations of the Quelccaya ice cap located at lat. 13° 56’ S., long. 70° 50’ W., in the Cordillera Oriental of southern Peru are presented. Ice cores to a depth of 15 m have been retrieved from the summit dome (5650 m), middle dome (5543 m), and south dome (5480 m) and sampled in detail for microparticle, oxygen-isotope, and total-β-activity measurements. Results of these core analyses indicate that although the summit of this ice cap is only 300 m above the annual snow line and the firn is temperate, an interpretable stratigraphic record is preserved. The marked seasonal ice stratigraphy is produced by the marked seasonal variation in regional precipitation. High concentrations of microparticles and β- radioactive material occur during the dry season (May-August). Microparticles deposited during the rainy season are larger than those deposited during the dry season. On the Quelccaya ice cap the most negative δ18O values occur during the warmer rainy season (the opposite occurs in polar regions). The near-surface mean δ value of – 21‰ is remarkably low for this tropical site where the measured mean annual air temperature is – 3°C The seasonality of the microparticles, total β activity, and isotope ratios offers the prospect of a climatic ice-core record from this tropical ice cap.

scholarly journals A Field Study of Brine Drainage and Oil Entrainment in First-Year Sea Ice

1979 ◽  
Vol 22 (88) ◽  
pp. 473-502 ◽  
Author(s):  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Growth And Development ◽  
Salt Transport ◽  
First Year ◽  
Field Observations ◽  
Melt Pond ◽  
Ice Surface ◽  
Melt Ponds ◽  
Brine Channel ◽  
Horizontal Layers

AbstractFrom field observations this paper describes the growth and development of first-year sea ice and its interaction with petroleum. In particular, when sea ice initially forms, there is an upward salt transport so that the ice surface has a highly saline layer, regardless of whether the initial ice is frazil, columnar, or slush ice. When the ice warms in the spring, because of the eutectic condition, the surface salt liquifies and drains through the ice, leading to the formation of top-to-bottom brine channels and void spaces in the upper part of the ice. If oil is released beneath winter ice, then the oil becomes entrained in thin lenses within the ice. In the spring, this oil flows up to the surface through the newly-opened brine channels and distributes itself within the brine-channel feeder systems, on the ice surface, and in horizontal layers in the upper part of the ice. The paper shows that these layers probably form from the interaction of the brine drainage with the percolation of melt water from surface snow down into the ice and the rise of the oil from below. Finally in the summer, the oil on the surface leads to melt-pond formation. The solar energy absorbed by the oil on the surface of these melt ponds eventually causes the melt pond to melt through the ice, and the oil is again released into the ocean.

scholarly journals Simulated features of the air-hydrate formation process in the Antarctic ice sheet at Vostok

1999 ◽  
Vol 29 ◽  
pp. 191-201 ◽  
Author(s):  
Andrey N. Salamatin ◽  
Vladimir Ya. Lipenkov ◽  
Takeo Hondoh ◽  
Tomoko Ikeda
Keyword(s):  
Ice Core ◽  
Hydrate Formation ◽  
Ice Cores ◽  
Air Bubbles ◽  
Air Bubble ◽  
Self Diffusion ◽  
Rate Limiting Step ◽  
Typical Time ◽  
Polar Ice Sheets ◽  
Selective Diffusion

AbstractA recently developed theory of post-nucleation conversion of an air bubble to air-hydrate crystal in ice is applied to simulate two different types of air-hydrate formation in polar ice sheets. The work is focused on interpretation of the Vostok (Antarctica) ice-core data. The hydrostatic compression of bubbles is the rate-limiting step of the phase transformation which is additionally influenced by selective diffusion of the gas components from neighboring air bubbles. The latter process leads to the gas fractionation resulting in lower (higher) N2/O2 ratios in air hydrates (coexisting bubbles) with respect to atmospheric air. The typical time of the post-nucleation conversion decreases at Vostok from 1300-200 a at the beginning to 50-3 a at the end of the transition zone. The model of the diffusive transport of the air constituents from air bubbles to hydrate crystals is constrained by the data of Raman spectra measurements. The oxygen and nitrogen self-diffusion (permeation) coefficients in ice are determined at 220 K as 4.5 × 10−8 and 9.5 × 10−8 mm2 a−1, respectively while the activation energy is estimated to be about 50 kJ mol−1. The gas-fractionation time-scale at Vostok, τF ∼300 a, appears to be two orders of magnitude less than the typical time of the air-hydrate nucleation, τz ∼30-35 ka, and thus the condition for the extreme gas fractionation, τF ≪ τz is satisfied. Application of the theory to the GRIP and GISP2 ice cores shows that on average, a significant gas fractionation cannot be expected for air hydrates in central Greenland. However, a noticeable (statistically valid) nitrogen enrichment might be observed in the last air bubbles at the end of the transition.

The role of sea ice for plastic pollution in the Arctic

2021 ◽  
Author(s):  
Ilka Peeken ◽  
Elisa Bergami ◽  
Ilaria Corsi ◽  
Benedikt Hufnagl ◽  
Christian Katlein ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Long Range ◽  
Environmental Concern ◽  
Ice Cores ◽  
Atlantic Water ◽  
The Arctic ◽  
Polar Regions ◽  
Plastic Pollution ◽  
The Arctic Ocean

&lt;p&gt;Marine plastic pollution is a growing worldwide environmental concern as recent reports indicate that increasing quantities of litter disperse into secluded environments, including Polar Regions. Plastic degrades into smaller fragments under the influence of sunlight, temperature changes, mechanic abrasion and wave action resulting in small particles &lt; 5mm called microplastics (MP). Sea ice cores, collected in the Arctic Ocean have so far revealed extremely high concentrations of very small microplastic particles, which might be transferred in the ecosystem with so far unknown consequences for the ice dependant marine food chain.&amp;#160; Sea ice has long been recognised as a transport vehicle for any contaminates entering the Arctic Ocean from various long range and local sources. The Fram Strait is hereby both, a major inflow gateway of warm Atlantic water, with any anthropogenic imprints and the major outflow region of sea ice originating from the Siberian shelves and carried via the Transpolar Drift. The studied sea ice revealed a unique footprint of microplastic pollution, which were related to different water masses and indicating different source regions. Climate change in the Arctic include loss of sea ice, therefore, large fractions of the embedded plastic particles might be released and have an impact on living systems. By combining modeling of sea ice origin and growth, MP particle trajectories in the water column as well as MPs long-range transport via particle tracking and transport models we get first insights &amp;#160;about the sources and pathways of MP in the Arctic Ocean and beyond and how this might affect the Arctic ecosystem.&lt;/p&gt;

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