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176 records – page 1 of 18.

21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes.

https://arctichealth.org/en/permalink/ahliterature297387
Source
Nat Commun. 2018 08 15; 9(1):3262
Publication Type
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
08-15-2018
Author
Katey Walter Anthony
Thomas Schneider von Deimling
Ingmar Nitze
Steve Frolking
Abraham Emond
Ronald Daanen
Peter Anthony
Prajna Lindgren
Benjamin Jones
Guido Grosse
Author Affiliation
Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA. kmwalteranthony@alaska.edu.
Source
Nat Commun. 2018 08 15; 9(1):3262
Date
08-15-2018
Language
English
Publication Type
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Alaska
Carbon - chemistry
Carbon Cycle
Carbon Dioxide - chemistry
Conservation of Natural Resources - methods - trends
Freezing
Geography
Geologic Sediments - chemistry
Global warming
Lakes - chemistry
Methane - chemistry
Models, Theoretical
Permafrost - chemistry
Soil - chemistry
Abstract
Permafrost carbon feedback (PCF) modeling has focused on gradual thaw of near-surface permafrost leading to enhanced carbon dioxide and methane emissions that accelerate global climate warming. These state-of-the-art land models have yet to incorporate deeper, abrupt thaw in the PCF. Here we use model data, supported by field observations, radiocarbon dating, and remote sensing, to show that methane and carbon dioxide emissions from abrupt thaw beneath thermokarst lakes will more than double radiative forcing from circumpolar permafrost-soil carbon fluxes this century. Abrupt thaw lake emissions are similar under moderate and high representative concentration pathways (RCP4.5 and RCP8.5), but their relative contribution to the PCF is much larger under the moderate warming scenario. Abrupt thaw accelerates mobilization of deeply frozen, ancient carbon, increasing 14C-depleted permafrost soil carbon emissions by ~125-190% compared to gradual thaw alone. These findings demonstrate the need to incorporate abrupt thaw processes in earth system models for more comprehensive projection of the PCF this century.
PubMed ID
30111815 View in PubMed
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[Activity of carbohydratephosphate metabolism enzymes in liver slices after freezing and thawing]

https://arctichealth.org/en/permalink/ahliterature13160
Source
Ukr Biokhim Zh. 1977 May-Jun;49(3):10-5
Publication Type
Article
Author
V I Lugovii
L I Zolochevs'ka
A M Dziuba
Source
Ukr Biokhim Zh. 1977 May-Jun;49(3):10-5
Language
Ukrainian
Publication Type
Article
Keywords
Animals
Drug Stability
English Abstract
Freezing
Glucosephosphate Dehydrogenase - metabolism
Hexokinase - metabolism
L-Lactate Dehydrogenase - metabolism
Liver - drug effects - enzymology
Phosphorylases - metabolism
Polyethylene Glycols - pharmacology
Rats
Subcellular Fractions - enzymology
Abstract
Activity of hexokinase, phosphorylase, glucoso-6-phosphate dehydrogenase lactate-dehydrogenase was studied in liver slices, homogenate and supernatant fraction after freezing at a rate of 1 degree/min down to -30 degrees C. The enzyme activity in homogenate and supernatant fraction does not change after freezing. A significant reduction in the activity of most enzymes that is followed by an increase in their activity in the freezing medium was observed in the experiments. Cryoprotectant polyethylene glycol, mol. wt. 300 and 1,000 (PEG-300 and PEG-1,000), partially prevents the observed changes in the enzyme activity; PEG-1,000 is more effective than PEG-300. Experimental results show that the main reason for the reduction of the enzyme activity observed after freezing the tissue slices is a decrease in the volume of intracellular enzyme proteins due to their leakage from the injured cellular elements into the exocellular medium.
PubMed ID
888219 View in PubMed
Less detail
Publication Type
Interactive/Multimedia
  1 website  
Author Affiliation
Alaska Sea Grant
Language
English
Geographic Location
U.S.
Publication Type
Interactive/Multimedia
Digital File Format
Web site (.html, .htm)
Keywords
One Health
Northern communities
Vulnerability & Adaptation
Animals
Climate change
Permafrost
Introduced species
Ice
Ecosystem
Floods
Freezing
Abstract
Seventeen-minute video produced by Alaska Sea Grant and NOAA Alaska Region.
Online Resources
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Adsorption inhibition as a mechanism of freezing resistance in polar fishes.

https://arctichealth.org/en/permalink/ahliterature46812
Source
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2589-93
Publication Type
Article
Date
Jun-1977
Author
J A Raymond
A L DeVries
Source
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2589-93
Date
Jun-1977
Language
English
Publication Type
Article
Keywords
Acclimatization
Adsorption
Animals
Blood Proteins - physiology
Cold Climate
Fishes - physiology
Freezing
Glycoproteins - blood
Kinetics
Microscopy, Electron, Scanning
Molecular Weight
Protein Conformation
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Species Specificity
Abstract
Polar fishes are known to have serum proteins and glycoproteins that protect them from freezing, by a noncolligative process. Measurements of antifreeze concentrations in ice and scanning electron micrographs of freeze-dried antifreeze solutions indicate that the antifreezes are incorporated in ice during freezing. The antifreezes also have a pronounced effect on the crystal habit of ice grown in their presence. Each of four antifreezes investigated caused ice to grow in long needles whose axes were parallel to the ice c axis. Together these results indicate the antifreezes adsorb to ice surfaces and inhibit their growth. A model in which adsorbed antifreezes raise the curvature of growth steps on the ice surface is proposed to account for the observed depression of the temperature at which freezing occurs and agrees well with experimental observations. The model is similar to one previously proposed for other cases of crystal growth inhibition.
PubMed ID
267952 View in PubMed
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Aircraft loading and freezer enhancements: lessons for medical research in remote communities.

https://arctichealth.org/en/permalink/ahliterature156317
Source
Air Med J. 2008 Jul-Aug;27(4):188-92
Publication Type
Article
Author
Roy Gagnon
Faith Gagnon
Constadina Panagiotopoulos
Author Affiliation
Endocrinology & Diabetes Unit, BC Children's Hospital, University of British Columbia, Vancouver, BC, Canada.
Source
Air Med J. 2008 Jul-Aug;27(4):188-92
Language
English
Publication Type
Article
Keywords
Aircraft
Canada
Child
Diabetes Mellitus, Type 2 - diagnosis
Endocrinology
Freezing
Glucose Intolerance - diagnosis
Health Services Research
Humans
Meteorological Concepts
Rural Health Services
Specimen Handling - instrumentation
Travel
Abstract
Type 2 diabetes (T2D) and impaired glucose tolerance (IGT), historically extremely rare in children, is becoming prevalent among First Nations children. In Canada, many of these children live in remote villages accessible only by float plane. Because T2D has many long-term health implications, prevention and early identification are critical.
We developed a process for sending a fully equipped endocrinology team to a remote community to screen the children for T2D and IGT. Float plane (sea plane) travel has several unexpected limitations for a medical research team. These include having to travel in good visibility (visual flight rules), limited payload capacity, and restriction against transporting dry ice. The benefits include avoiding the usual security restrictions.
We developed and tested a custom-built insulation jacket and system of backup battery packs for the countertop -25 degrees C freezer (in lieu of dry ice) to transport frozen blood samples from the village to our hospital's laboratory. We also ensured that the five-member research team, its equipment, and the consumable supplies stayed within the maximum takeoff weight of the airplane and met center-of-gravity criteria to ensure a safe flight.
Using the insulated freezer, sample integrity was maintained throughout the flight, and a safe weight-and-balance trip was achieved for the team and supplies. The team obtained complete T2D screening data on 88% of children in the remote community.
PubMed ID
18603216 View in PubMed
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Algae are melting away the Greenland ice sheet.

https://arctichealth.org/en/permalink/ahliterature275518
Source
Nature. 2016 Jul 21;535(7612):336
Publication Type
Article
Date
Jul-21-2016

Analysis of Seasonal Active Layer Dynamics & Fate, Transport & Transformation of Three Chemical Clusters in Permafrost-Affected Soils.

https://arctichealth.org/en/permalink/ahliterature297121
Source
RPIC, Regional Workshop on Federal Contaminated Sites, Edmonton, Alberta. 37 slides.
Publication Type
Conference/Meeting Material
Date
June 3, 2015
Active Layer: Top layer of the permanently frozen soil undergoes seasonal thawing and freezing Dynamics: •  Spatial and Temporal Extent •  Hydrology •  Temperature •  Soil Heterogeneity/Geochemistry/Geochemical Properties •  Mixing of Soil & Sediment; Surface water & Groundwater 10
  1 document  
Author
Mohapatra, Asish
Author Affiliation
Contaminated Sites, Health Canada, Prairie Region - Alberta
Source
RPIC, Regional Workshop on Federal Contaminated Sites, Edmonton, Alberta. 37 slides.
Date
June 3, 2015
Language
English
Geographic Location
Canada
Publication Type
Conference/Meeting Material
File Size
1359038
Keywords
Permafrost
Soils
Hydrologic dynamics
Thermal dynamics
Freezing
Groundwater
Chemical transport
Climate change
Documents
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Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

https://arctichealth.org/en/permalink/ahliterature270039
Source
PLoS One. 2015;10(3):e0116084
Publication Type
Article
Date
2015
Author
Lorraine M McGill
Adam J Shannon
Davide Pisani
Marie-Anne Félix
Hans Ramløv
Ilona Dix
David A Wharton
Ann M Burnell
Source
PLoS One. 2015;10(3):e0116084
Date
2015
Language
English
Publication Type
Article
Keywords
Adaptation, Physiological
Animals
Arctic Regions
Freezing
Iceland
Nematoda - classification - physiology
Phylogeny
Principal Component Analysis
Abstract
Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent "ecological fitting" of freezing-tolerant anhydrobiotic propagules to the respective abiotic conditions in Ross Island and Surtsey.
Notes
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PubMed ID
25747673 View in PubMed
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Antifreeze glycoproteins from Polar fish. Effects of freezing conditions on cooperative function.

https://arctichealth.org/en/permalink/ahliterature3393
Source
J Biol Chem. 1980 Jan 25;255(2):659-62
Publication Type
Article
Date
Jan-25-1980
Author
D M Mulvihill
K F Geoghegan
Y. Yeh
K. DeRemer
D T Osuga
F C Ward
R E Feeney
Source
J Biol Chem. 1980 Jan 25;255(2):659-62
Date
Jan-25-1980
Language
English
Publication Type
Article
Keywords
Animals
Arctic Regions
Fishes - blood
Freezing
Glycopeptides - blood
Glycoproteins - blood
Molecular Weight
Research Support, U.S. Gov't, P.H.S.
Sodium Chloride
Abstract
Antifreeze glycoproteins and glycopeptides that function noncolligatively contribute one-third of the freezing temperature depression in the blood serum of some polar fishes and enable them to survive at low temperature (-1.9 degree C). There are at least eight closely related glycoproteins and glycopeptides ranging in molecular weight from 32,000 to 2,600 and numbered 1 to 8 in order of decreasing size. Under conditions of negligible supercooling, the glycopeptides have weaker antifreeze activity than the glycoproteins (20% on a weight basis, or 5% on a molar basis); in mixtures of both, their activities are additive. When nucleation is initiated in supercooled solutions (-4 to -5 degrees C), the glycopeptides are inactive, while the glycoproteins still show activity; when mixtures of both are nucleated in supercooled solutions, cooperative potentiation occurs, and the full activities of the glycopeptides are found. On nucleation of supercooled solutions of the glycoprotein alone or of the mixtures, the temperature rises above the freezing temperature ("overshoots") to an extent dependent upon the extent of supercooling; the temperature of the sample then decreases to form a plateau at the true freezing temperature.
PubMed ID
7356636 View in PubMed
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176 records – page 1 of 18.