Skip header and navigation

Refine By

50 records – page 1 of 5.

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

Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years.

https://arctichealth.org/en/permalink/ahliterature294791
Source
Nature. 2018 04; 556(7700):227-230
Publication Type
Historical Article
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
04-2018
Author
David J R Thornalley
Delia W Oppo
Pablo Ortega
Jon I Robson
Chris M Brierley
Renee Davis
Ian R Hall
Paola Moffa-Sanchez
Neil L Rose
Peter T Spooner
Igor Yashayaev
Lloyd D Keigwin
Author Affiliation
Department of Geography, University College London, London, UK. d.thornalley@cantab.net.
Source
Nature. 2018 04; 556(7700):227-230
Date
04-2018
Language
English
Publication Type
Historical Article
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Arctic Regions
Atlantic Ocean
Climate Change - statistics & numerical data
Convection
Fresh Water - analysis
Greenland
History, 15th Century
History, 16th Century
History, 17th Century
History, 18th Century
History, 19th Century
History, 20th Century
History, 21st Century
History, Medieval
Ice Cover - chemistry
Newfoundland and Labrador
Oceans and Seas
Reproducibility of Results
Seawater - analysis
Time Factors
Water Movements
Abstract
The Atlantic meridional overturning circulation (AMOC) is a system of ocean currents that has an essential role in Earth's climate, redistributing heat and influencing the carbon cycle1, 2. The AMOC has been shown to be weakening in recent years 1 ; this decline may reflect decadal-scale variability in convection in the Labrador Sea, but short observational datasets preclude a longer-term perspective on the modern state and variability of Labrador Sea convection and the AMOC1, 3-5. Here we provide several lines of palaeo-oceanographic evidence that Labrador Sea deep convection and the AMOC have been anomalously weak over the past 150 years or so (since the end of the Little Ice Age, LIA, approximately AD 1850) compared with the preceding 1,500 years. Our palaeoclimate reconstructions indicate that the transition occurred either as a predominantly abrupt shift towards the end of the LIA, or as a more gradual, continued decline over the past 150 years; this ambiguity probably arises from non-AMOC influences on the various proxies or from the different sensitivities of these proxies to individual components of the AMOC. We suggest that enhanced freshwater fluxes from the Arctic and Nordic seas towards the end of the LIA-sourced from melting glaciers and thickened sea ice that developed earlier in the LIA-weakened Labrador Sea convection and the AMOC. The lack of a subsequent recovery may have resulted from hysteresis or from twentieth-century melting of the Greenland Ice Sheet 6 . Our results suggest that recent decadal variability in Labrador Sea convection and the AMOC has occurred during an atypical, weak background state. Future work should aim to constrain the roles of internal climate variability and early anthropogenic forcing in the AMOC weakening described here.
Notes
CommentIn: Nature. 2018 Apr;556(7700):149 PMID 29643490
CommentIn: Nature. 2018 Apr;556(7700):180-181 PMID 29636556
PubMed ID
29643484 View in PubMed
Less detail

An ultra-clean firn core from the Devon Island Ice Cap, Nunavut, Canada, retrieved using a titanium drill specially designed for trace element studies.

https://arctichealth.org/en/permalink/ahliterature82660
Source
J Environ Monit. 2006 Mar;8(3):406-13
Publication Type
Article
Date
Mar-2006
Author
Zheng J.
Fisher D.
Blake E.
Hall G.
Vaive J.
Krachler M.
Zdanowicz C.
Lam J.
Lawson G.
Shotyk W.
Author Affiliation
GSC Northern Canada, Geological Survey of Canada, Natural Resources Canada, 601 Booth Street, Ottawa, Canada K1A 0E8. jzheng@nrcan.gc.ca
Source
J Environ Monit. 2006 Mar;8(3):406-13
Date
Mar-2006
Language
English
Publication Type
Article
Keywords
Air Pollutants - analysis
Arctic Regions
Cadmium - analysis
Environmental Monitoring - instrumentation - methods
Ice Cover - chemistry
Lead - analysis
Metals - analysis
Nunavut
Time Factors
Titanium
Abstract
An electromechanical drill with titanium barrels was used to recover a 63.7 m long firn core from Devon Island Ice Cap, Nunavut, Canada, representing 155 years of precipitation. The core was processed and analysed at the Geological Survey of Canada by following strict clean procedures for measurements of Pb and Cd at concentrations at or below the pg g(-1) level. This paper describes the effectiveness of the titanium drill with respect to contamination during ice core retrieval and evaluates sample-processing procedures in laboratories. The results demonstrate that: (1) ice cores retrieved with this titanium drill are of excellent quality with metal contamination one to four orders of magnitude less than those retrieved with conventional drills; (2) the core cleaning and sampling protocols used were effective, contamination-free, and adequate for analysis of the metals (Pb and Cd) at low pg g(-1) levels; and (3) results from 489 firn core samples analysed in this study are comparable with published data from other sites in the Arctic, Greenland and the Antarctic.
PubMed ID
16528426 View in PubMed
Less detail

Arctic tipping points: governance in turbulent times.

https://arctichealth.org/en/permalink/ahliterature127683
Source
Ambio. 2012 Feb;41(1):75-84
Publication Type
Article
Date
Feb-2012
Author
Oran R Young
Author Affiliation
Bren School of Environmental Science and Management, University of California (Santa Barbara), 4518 Bren Hall, UCSB, Santa Barbara, CA 93106-5131, USA. oran.young@gmail.com
Source
Ambio. 2012 Feb;41(1):75-84
Date
Feb-2012
Language
English
Publication Type
Article
Keywords
Arctic Regions
Climate
Conservation of Natural Resources - economics
Ecosystem
Environmental monitoring
Government
Greenhouse Effect
Humans
Ice Cover - chemistry
Oceans and Seas
Politics
Population Dynamics
Water Pollutants, Chemical - analysis - toxicity
Abstract
Interacting forces of climate change and globalization are transforming the Arctic. Triggered by a non-linear shift in sea ice, this transformation has unleashed mounting interest in opportunities to exploit the region's natural resources as well as growing concern about environmental, economic, and political issues associated with such efforts. This article addresses the implications of this transformation for governance, identifies limitations of existing arrangements, and explores changes needed to meet new demands. It advocates the development of an Arctic regime complex featuring flexibility across issues and adaptability over time along with an enhanced role for the Arctic Council both in conducting policy-relevant assessments and in promoting synergy in interactions among the elements of the emerging Arctic regime complex. The emphasis throughout is on maximizing the fit between the socioecological features of the Arctic and the character of the governance arrangements needed to steer the Arctic toward a sustainable future.
Notes
Cites: Science. 2006 Aug 4;313(5787):617-816888124
PubMed ID
22270707 View in PubMed
Less detail

Bacterial communities of surface mixed layer in the Pacific sector of the western Arctic Ocean during sea-ice melting.

https://arctichealth.org/en/permalink/ahliterature257813
Source
PLoS One. 2014;9(1):e86887
Publication Type
Article
Date
2014
Author
Dukki Han
Ilnam Kang
Ho Kyung Ha
Hyun Cheol Kim
Ok-Sun Kim
Bang Yong Lee
Jang-Cheon Cho
Hor-Gil Hur
Yoo Kyung Lee
Author Affiliation
Korea Polar Research Institute, KIOST, Incheon, Republic of Korea ; School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
Source
PLoS One. 2014;9(1):e86887
Date
2014
Language
English
Publication Type
Article
Keywords
Alphaproteobacteria - classification - genetics - growth & development
Ammonium Compounds - analysis
Arctic Regions
Bacteria - classification - genetics - growth & development
Ecosystem
Flavobacteriaceae - classification - growth & development
Fresh Water - chemistry - microbiology
Gammaproteobacteria - classification - genetics - growth & development
Geography
Ice Cover - chemistry - microbiology
Linear Models
Nitrates - analysis
Nitrogen Dioxide - analysis
Oceans and Seas
Phosphates - analysis
Phylogeny
RNA, Ribosomal, 16S - genetics
Salinity
Seasons
Seawater - chemistry - microbiology
Sequence Analysis, DNA
Silicon Dioxide - analysis
Temperature
Abstract
From July to August 2010, the IBRV ARAON journeyed to the Pacific sector of the Arctic Ocean to monitor bacterial variation in Arctic summer surface-waters, and temperature, salinity, fluorescence, and nutrient concentrations were determined during the ice-melting season. Among the measured physicochemical parameters, we observed a strong negative correlation between temperature and salinity, and consequently hypothesized that the melting ice decreased water salinity. The bacterial community compositions of 15 samples, includicng seawater, sea-ice, and melting pond water, were determined using a pyrosequencing approach and were categorized into three habitats: (1) surface seawater, (2) ice core, and (3) melting pond. Analysis of these samples indicated the presence of local bacterial communities; a deduction that was further corroborated by the discovery of seawater- and ice-specific bacterial phylotypes. In all samples, the Alphaproteobacteria, Flavobacteria, and Gammaproteobacteria taxa composed the majority of the bacterial communities. Among these, Alphaproteobacteria was the most abundant and present in all samples, and its variation differed among the habitats studied. Linear regression analysis suggested that changes in salinity could affect the relative proportion of Alphaproteobacteria in the surface water. In addition, the species-sorting model was applied to evaluate the population dynamics and environmental heterogeneity in the bacterial communities of surface mixed layer in the Arctic Ocean during sea-ice melting.
Notes
Cites: Appl Environ Microbiol. 2002 Feb;68(2):505-1811823184
Cites: Nature. 2002 Dec 19-26;420(6917):806-1012490947
Cites: Appl Environ Microbiol. 2004 Aug;70(8):4921-915294832
Cites: Proc Natl Acad Sci U S A. 2006 Jan 17;103(3):626-3116407148
Cites: Science. 2006 Mar 10;311(5766):1461-416527980
Cites: Appl Environ Microbiol. 2006 Jul;72(7):5069-7216820507
Cites: Mol Ecol. 2007 Feb;16(4):867-8017284217
Cites: Ecology. 2007 Sep;88(9):2154-6117918394
Cites: Proc Natl Acad Sci U S A. 2007 Dec 18;104(51):20404-918077371
Cites: Nature. 2008 Apr 10;452(7188):741-418337719
Cites: Mol Biol Evol. 2011 Oct;28(10):2731-921546353
Cites: ISME J. 2012 Jan;6(1):11-2021716307
Cites: PLoS One. 2011;6(12):e2731022194782
Cites: FEMS Microbiol Rev. 2013 May;37(3):303-3523062173
Cites: Environ Microbiol. 2008 Sep;10(9):2200-1018637951
Cites: ISME J. 2009 Mar;3(3):283-9519052630
Cites: Environ Microbiol. 2009 Apr;11(4):971-8019077007
Cites: Nature. 2009 May 14;459(7244):193-919444205
Cites: Microb Ecol. 2009 Nov;58(4):737-5219547939
Cites: Appl Environ Microbiol. 2009 Dec;75(23):7537-4119801464
Cites: Science. 2009 Dec 18;326(5960):1694-719892944
Cites: Mol Biol Evol. 2010 Feb;27(2):347-5719808864
Cites: Proc Natl Acad Sci U S A. 2009 Dec 29;106(52):22427-3220018741
Cites: ISME J. 2010 Feb;4(2):151-819710708
Cites: Extremophiles. 2010 Mar;14(2):205-1220066448
Cites: ISME J. 2010 Apr;4(4):564-7620010630
Cites: ISME J. 2010 Jun;4(6):729-3820130658
Cites: Environ Microbiol. 2010 May;12(5):1132-4320132284
Cites: Environ Microbiol. 2010 Jul;12(7):1828-4120192970
Cites: Science. 2010 Jul 30;329(5991):556-920651119
Cites: Appl Environ Microbiol. 2011 May;77(10):3234-4321460114
Cites: ISME J. 2011 Jul;5(7):1086-9421270841
Cites: Int J Syst Evol Microbiol. 2011 Aug;61(Pt 8):1899-90520833882
PubMed ID
24497990 View in PubMed
Less detail

The causes of sea-level rise since 1900.

https://arctichealth.org/en/permalink/ahliterature305014
Source
Nature. 2020 08; 584(7821):393-397
Publication Type
Historical Article
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
08-2020
Author
Thomas Frederikse
Felix Landerer
Lambert Caron
Surendra Adhikari
David Parkes
Vincent W Humphrey
Sönke Dangendorf
Peter Hogarth
Laure Zanna
Lijing Cheng
Yun-Hao Wu
Author Affiliation
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. thomas.frederikse@jpl.nasa.gov.
Source
Nature. 2020 08; 584(7821):393-397
Date
08-2020
Language
English
Publication Type
Historical Article
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Environmental monitoring
Global Warming - statistics & numerical data
Greenland
History, 20th Century
History, 21st Century
Hot Temperature
Ice Cover - chemistry
Probability
Seawater - analysis - chemistry
Uncertainty
Abstract
The rate of global-mean sea-level rise since 1900 has varied over time, but the contributing factors are still poorly understood1. Previous assessments found that the summed contributions of ice-mass loss, terrestrial water storage and thermal expansion of the ocean could not be reconciled with observed changes in global-mean sea level, implying that changes in sea level or some contributions to those changes were poorly constrained2,3. Recent improvements to observational data, our understanding of the main contributing processes to sea-level change and methods for estimating the individual contributions, mean another attempt at reconciliation is warranted. Here we present a probabilistic framework to reconstruct sea level since 1900 using independent observations and their inherent uncertainties. The sum of the contributions to sea-level change from thermal expansion of the ocean, ice-mass loss and changes in terrestrial water storage is consistent with the trends and multidecadal variability in observed sea level on both global and basin scales, which we reconstruct from tide-gauge records. Ice-mass loss-predominantly from glaciers-has caused twice as much sea-level rise since 1900 as has thermal expansion. Mass loss from glaciers and the Greenland Ice Sheet explains the high rates of global sea-level rise during the 1940s, while a sharp increase in water impoundment by artificial reservoirs is the main cause of the lower-than-average rates during the 1970s. The acceleration in sea-level rise since the 1970s is caused by the combination of thermal expansion of the ocean and increased ice-mass loss from Greenland. Our results reconcile the magnitude of observed global-mean sea-level rise since 1900 with estimates based on the underlying processes, implying that no additional processes are required to explain the observed changes in sea level since 1900.
PubMed ID
32814886 View in PubMed
Less detail

Climate change: the Arctic tells its story.

https://arctichealth.org/en/permalink/ahliterature95726
Source
Nature. 2006 Jun 1;441(7093):579-81
Publication Type
Article
Date
Jun-1-2006
Author
Stoll Heather M
Source
Nature. 2006 Jun 1;441(7093):579-81
Date
Jun-1-2006
Language
English
Publication Type
Article
Keywords
Arctic Regions
Atmosphere - chemistry
Carbon Dioxide - analysis
Cold Climate
Ferns - physiology
Geologic Sediments - analysis
Greenhouse Effect
Ice Cover - chemistry
Seawater - chemistry
Temperature
Time Factors
Notes
Comment On: Nature. 2006 Jun 1;441(7093):601-516738653
Comment On: Nature. 2006 Jun 1;441(7093):606-916752440
Comment On: Nature. 2006 Jun 1;441(7093):610-316752441
PubMed ID
16738644 View in PubMed
Less detail

Continuous summer export of nitrogen-rich organic matter from the Greenland Ice Sheet inferred by ultrahigh resolution mass spectrometry.

https://arctichealth.org/en/permalink/ahliterature264617
Source
Environ Sci Technol. 2014 Dec 16;48(24):14248-57
Publication Type
Article
Date
Dec-16-2014
Author
Emily C Lawson
Maya P Bhatia
Jemma L Wadham
Elizabeth B Kujawinski
Source
Environ Sci Technol. 2014 Dec 16;48(24):14248-57
Date
Dec-16-2014
Language
English
Publication Type
Article
Keywords
Carbon
Climate change
Ecosystem
Fourier Analysis
Greenland
Ice Cover - chemistry
Mass Spectrometry - methods
Nitrogen - chemistry
Seasons
Time Factors
Abstract
Runoff from glaciers and ice sheets has been acknowledged as a potential source of bioavailable dissolved organic matter (DOM) to downstream ecosystems. This source may become increasingly significant as glacial melt rates increase in response to future climate change. Recent work has identified significant concentrations of bioavailable carbon and iron in Greenland Ice Sheet (GrIS) runoff. The flux characteristics and export of N-rich DOM are poorly understood. Here, we employed electrospray ionization (ESI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to determine the elemental compositions of DOM molecules in supraglacial water and subglacial runoff from a large GrIS outlet glacier. We provide the first detailed temporal analysis of the molecular composition of DOM exported over a full melt season. We find that DOM pools in supraglacial and subglacial runoff are compositionally diverse and that N-rich material is continuously exported throughout the melt season, as the snowline retreats further inland. Identification of protein-like compounds and a high proportion of N-rich DOM, accounting for 27-41% of the DOM molecules identified by ESI FT-ICR MS, may suggest a microbial provenance and high bioavailability of glacially exported DOM to downstream microbial communities.
PubMed ID
25375225 View in PubMed
Less detail

Deep water masses and sediments are main compartments for polychlorinated biphenyls in the Arctic Ocean.

https://arctichealth.org/en/permalink/ahliterature257772
Source
Environ Sci Technol. 2014 Jun 17;48(12):6719-25
Publication Type
Article
Date
Jun-17-2014
Author
Anna Sobek
Örjan Gustafsson
Author Affiliation
Department of Applied Environmental Science (ITM) and ‡Bolin Centre for Climate Research, Stockholm University , 10691, Stockholm Sweden.
Source
Environ Sci Technol. 2014 Jun 17;48(12):6719-25
Date
Jun-17-2014
Language
English
Publication Type
Article
Keywords
Arctic Regions
Geologic Sediments - chemistry
Ice Cover - chemistry
Oceans and Seas
Polychlorinated biphenyls - analysis
Uncertainty
Water - chemistry
Water Pollutants, Chemical - analysis
Abstract
There is a wealth of studies of polychlorinated biphenyls (PCB) in surface water and biota of the Arctic Ocean. Still, there are no observation-based assessments of PCB distribution and inventories in and between the major Arctic Ocean compartments. Here, the first water column distribution of PCBs in the central Arctic Ocean basins (Nansen, Amundsen, and Makarov) is presented, demonstrating nutrient-like vertical profiles with 5-10 times higher concentrations in the intermediate and deep water masses than in surface waters. The consistent vertical profiles in all three Arctic Ocean basins likely reflect buildup of PCBs transported from the shelf seas and from dissolution and/or mineralization of settling particles. Combined with measurement data on PCBs in other Arctic Ocean compartments collected over the past decade, the total Arctic Ocean inventory of ?7PCB was estimated to 182 ± 40 t (±1 standard error of the mean), with sediments (144 ± 40 t), intermediate (5 ± 1 t) and deep water masses (30 ± 2 t) storing 98% of the PCBs in the Arctic Ocean. Further, we used hydrographic and carbon cycle parametrizations to assess the main pathways of PCBs into and out of the Arctic Ocean during the 20th century. River discharge appeared to be the major pathway for PCBs into the Arctic Ocean with 115 ± 11 t, followed by ocean currents (52 ± 17 t) and net atmospheric deposition (30 ± 28 t). Ocean currents provided the only important pathway out of the Arctic Ocean, with an estimated cumulative flux of 22 ± 10 t. The observation-based inventory of ?7PCB of 182 ± 40 t is consistent with the contemporary inventory based on cumulative fluxes for ?7PCB of 173 ± 36 t. Information on the concentration and distribution of PCBs in the deeper compartments of the Arctic Ocean improves our understanding of the large-scale fate of POPs in the Arctic and may also provide a means to test and improve models used to assess the fate of organic pollutants in the Arctic.
PubMed ID
24844123 View in PubMed
Less detail

The derivation of radionuclide transfer parameters for and dose-rates to an adult ringed seal (Phoca hispida) in an Arctic environment.

https://arctichealth.org/en/permalink/ahliterature80716
Source
J Environ Radioact. 2006;90(3):197-209
Publication Type
Article
Date
2006
Author
Gwynn J P
Brown J E
Kovacs K M
Lydersen C.
Author Affiliation
Norwegian Radiation Protection Authority, Environmental Radioactivity, Polar Environmental Centre, NO-9296 Tromsø, Norway. justin.gwynn@nrpa.no
Source
J Environ Radioact. 2006;90(3):197-209
Date
2006
Language
English
Publication Type
Article
Keywords
Animals
Bone and Bones - chemistry
Half-Life
Ice Cover - chemistry
Kidney - chemistry
Liver - chemistry
Models, Biological
Muscles - chemistry
Phoca - metabolism
Radiation Dosage
Radioisotopes - analysis - metabolism
Seawater - chemistry
Svalbard
Water Pollutants, Radioactive - analysis - metabolism
Abstract
Radionuclide transfer parameters and dose-rates for an adult ringed seal from Svalbard have been determined based on empirical and estimated tissue activity concentrations and detailed dietary and habitat information. Whole-body equivalent concentration factors determined for anthropogenic radionuclides ranged from 10(1) ((90)Sr) to 10(2) ((137)Cs, (238)Pu and (239,240)Pu), while natural radionuclides ranged from 10(2) ((210)Pb) to 10(4) ((210)Po). Employing a dietary composition of 40% fish, 40% zooplankton and 20% benthic invertebrates, a whole-body biological half-life of 29 days was derived for (137)Cs. A total dose-rate of approximately 0.19microGyh(-1) (1.7mGya(-1)) was derived for an adult ringed seal; this dose-rate is virtually entirely attributable to the internal components of (210)Po and (40)K. The dose-rates associated with the presence of anthropogenically derived radionuclides in the present assessment fall many orders of magnitude below the dose-rates at which any biological effects would be expected.
PubMed ID
16965842 View in PubMed
Less detail

50 records – page 1 of 5.