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464 records – page 1 of 47.

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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137Cs in puddle sediments as timescale tracer in urban environment.

https://arctichealth.org/en/permalink/ahliterature268380
Source
J Environ Radioact. 2015 Apr;142:9-13
Publication Type
Article
Date
Apr-2015
Author
Andrian A Seleznev
Ilia V Yarmoshenko
Alexander P Sergeev
Source
J Environ Radioact. 2015 Apr;142:9-13
Date
Apr-2015
Language
English
Publication Type
Article
Keywords
Cesium Radioisotopes - analysis
Cities
Environmental monitoring
Geologic Sediments - analysis
Radiation monitoring
Russia
Soil Pollutants, Radioactive - analysis
Time Factors
Abstract
The (137)Cs-based chronological approach is suggested to identify the age of urban landscapes and the chronology of pollution of soil in residential areas. Three main pivot points constitute the basis of the chronological approach: beginning of the Atomic Era in 1945, the maximum input in 1963 and the Chernobyl accident in 1986. Application of (137)Cs as a timescale tracer was tested on the example of Ekaterinburg, a city in the Middle Urals region of Russia. The sampling of recent urban sediments of micro water bodies (puddles) was carried out in 210 locations in 2007-2010. The concentrations of Pb, Zn, Cu, Ni, Co, Mn and Fe, and activity concentrations of (137)Cs were measured. It was found that the (137)Cs concentrations in the puddle sediments correlated with the age of surrounding buildings determined by the year of construction. The correlations between the concentrations of metals and (137)Cs in the puddle sediments identified the major pollutants of the urban area, assessing their background concentrations and obtaining the average annual inputs.
PubMed ID
25615884 View in PubMed
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A 700-year paleoecological record of boreal ecosystem responses to climatic variation from Alaska.

https://arctichealth.org/en/permalink/ahliterature85780
Source
Ecology. 2008 Mar;89(3):729-43
Publication Type
Article
Date
Mar-2008
Author
Tinner Willy
Bigler Christian
Gedye Sharon
Gregory-Eaves Irene
Jones Richard T
Kaltenrieder Petra
Krähenbühl Urs
Hu Feng Sheng
Author Affiliation
Institute of Plant Sciences and Oeschger Center for Climate Change Research, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. willy.tinner@ips.unibe.ch
Source
Ecology. 2008 Mar;89(3):729-43
Date
Mar-2008
Language
English
Publication Type
Article
Keywords
Alaska
Climate
Diatoms
Ecosystem
Fires
Forestry
Fossils
Geologic sediments
Greenhouse Effect
Ice Cover
Plant Physiology
Pollen
Time Factors
Trees
Abstract
Recent observations and model simulations have highlighted the sensitivity of the forest-tundra ecotone to climatic forcing. In contrast, paleoecological studies have not provided evidence of tree-line fluctuations in response to Holocene climatic changes in Alaska, suggesting that the forest-tundra boundary in certain areas may be relatively stable at multicentennial to millennial time scales. We conducted a multiproxy study of sediment cores from an Alaskan lake near the altitudinal limits of key boreal-forest species. Paleoecological data were compared with independent climatic reconstructions to assess ecosystem responses of the forest tundra boundary to Little Ice Age (LIA) climatic fluctuations. Pollen, diatom, charcoal, macrofossil, and magnetic analyses provide the first continuous record of vegetation fire-climate interactions at decadal to centennial time scales during the past 700 years from southern Alaska. Boreal-forest diebacks characterized by declines of Picea mariana, P. glauca, and tree Betula occurred during the LIA (AD 1500-1800), whereas shrubs (Alnus viridis, Betula glandulosa/nana) and herbaceous taxa (Epilobium, Aconitum) expanded. Marked increases in charcoal abundance and changes in magnetic properties suggest increases in fire importance and soil erosion during the same period. In addition, the conspicuous reduction or disappearance of certain aquatic (e.g., Isoetes, Nuphar, Pediastrum) and wetland (Sphagnum) plants and major shifts in diatom assemblages suggest pronounced lake-level fluctuations and rapid ecosystem reorganization in response to LIA climatic deterioration. Our results imply that temperature shifts of 1-2 degrees C, when accompanied by major changes in moisture balance, can greatly alter high-altitudinal terrestrial, wetland, and aquatic ecosystems, including conversion between boreal-forest tree line and tundra. The climatic and ecosystem variations in our study area appear to be coherent with changes in solar irradiance, suggesting that changes in solar activity contributed to the environmental instability of the past 700 years.
PubMed ID
18459336 View in PubMed
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The 1300-year dynamics of vegetation cover in the Lake Shira depression (Khakassia, Siberia, Russia) reconstructed on the basis of bottom sediments.

https://arctichealth.org/en/permalink/ahliterature263196
Source
Dokl Biol Sci. 2014 Jul;457(1):248-51
Publication Type
Article
Date
Jul-2014
Author
K E Vershinin
D Yu Rogozin
Source
Dokl Biol Sci. 2014 Jul;457(1):248-51
Date
Jul-2014
Language
English
Publication Type
Article
Keywords
Biodiversity
Biomass
Geologic sediments
Lakes
Paleontology
Plant Physiological Processes
Siberia
PubMed ID
25172593 View in PubMed
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[Accumulation and distribution of 137Cs and 90Sr radionuclides in the components of water-bottom sediments-macrophytes of Lake Malye Kirpichiky].

https://arctichealth.org/en/permalink/ahliterature263700
Source
Radiats Biol Radioecol. 2014 Nov-Dec;54(6):650-6
Publication Type
Article
Author
K V Kablova
V V Deryagin
S G Levina
A A Sutyagin
Source
Radiats Biol Radioecol. 2014 Nov-Dec;54(6):650-6
Language
Russian
Publication Type
Article
Keywords
Cesium Radioisotopes - analysis
Ecosystem
Fresh Water
Geologic Sediments - analysis
Humans
Lakes
Radioactive Hazard Release
Russia
Strontium Radioisotopes - analysis
Water Pollutants, Radioactive - analysis
Abstract
This research work is devoted to analyzing the processes of accumulation and distribution of long-lived radionuclides of 90Sr and 137Cs in the components of water-sediment-macrophytes of Lake Malye Kirpichiky (Chelyabinsk region). The characteristic features of redistribution of radioactive substances, depending on the texture of the bottom sediments of the lake and the species composition of aquatic vegetation are shown. Also shown is the total stock of radionuclides in water and bottom sediments. The coefficients of 90Sr and 137Cs accumulation in bottom sediments and macrophytes have been calculated.
PubMed ID
25980292 View in PubMed
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Accumulation of lead (Pb) in brown trout (Salmo trutta) from a lake downstream a former shooting range.

https://arctichealth.org/en/permalink/ahliterature279581
Source
Ecotoxicol Environ Saf. 2017 Jan;135:327-336
Publication Type
Article
Date
Jan-2017
Author
Espen Mariussen
Lene Sørlie Heier
Hans Christian Teien
Marit Nandrup Pettersen
Tor Fredrik Holth
Brit Salbu
Bjørn Olav Rosseland
Source
Ecotoxicol Environ Saf. 2017 Jan;135:327-336
Date
Jan-2017
Language
English
Publication Type
Article
Keywords
Animals
Antimony - analysis
Bone and Bones - chemistry
Copper - analysis
Firearms
Geologic Sediments - analysis
Gills - chemistry
Kidney - chemistry
Lakes
Lead - analysis
Norway
Sports
Trout - blood - metabolism
Water Pollutants, Chemical - analysis
Zinc - analysis
Zygote - chemistry - drug effects
Abstract
An environmental survey was performed in Lake Kyrtj?nn, a small lake within an abandoned shooting range in the south of Norway. In Lake Kyrtj?nn the total water concentrations of Pb (14?g/L), Cu (6.1?g/L) and Sb (1.3?g/L) were elevated compared to the nearby reference Lake Stitj?nn, where the total concentrations of Pb, Cu and Sb were 0.76, 1.8 and 0.12?g/L, respectively. Brown trout (Salmo trutta) from Lake Kyrtj?nn had very high levels of Pb in bone (104mg/kg w.w.), kidney (161mg/kg w.w.) and the gills (137mg/kg d.w), and a strong inhibition of the ALA-D enzyme activity were observed in the blood (24% of control). Dry fertilized brown trout eggs were placed in the small outlet streams from Lake Kyrtj?nn and the reference lake for 6 months, and the concentrations of Pb and Cu in eggs from the Lake Kyrtj?nn stream were significantly higher than in eggs from the reference. More than 90% of Pb accumulated in the egg shell, whereas more than 80% of the Cu and Zn accumulated in the egg interior. Pb in the lake sediments was elevated in the upper 2-5cm layer (410-2700mg/kg d.w), and was predominantly associated with redox sensitive fractions (e.g., organic materials, hydroxides) indicating low potential mobility and bioavailability of the deposited Pb. Only minor amounts of Cu and Sb were deposited in the sediments. The present work showed that the adult brown trout, as well as fertilized eggs and alevins, may be subjected to increased stress due to chronic exposure to Pb, whereas exposure to Cu, Zn and Sb were of less importance.
PubMed ID
27770648 View in PubMed
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Active Microbial Communities Inhabit Sulphate-Methane Interphase in Deep Bedrock Fracture Fluids in Olkiluoto, Finland.

https://arctichealth.org/en/permalink/ahliterature274433
Source
Biomed Res Int. 2015;2015:979530
Publication Type
Article
Date
2015
Author
Malin Bomberg
Mari Nyyssönen
Petteri Pitkänen
Anne Lehtinen
Merja Itävaara
Source
Biomed Res Int. 2015;2015:979530
Date
2015
Language
English
Publication Type
Article
Keywords
Bacteria - genetics - metabolism
Base Sequence
Ecosystem
Finland
Geologic Sediments - microbiology
Groundwater - microbiology
High-Throughput Nucleotide Sequencing
Methane - metabolism
Phylogeny
RNA, Messenger - genetics - metabolism
RNA, Ribosomal, 16S - genetics
Sulfates - metabolism
Abstract
Active microbial communities of deep crystalline bedrock fracture water were investigated from seven different boreholes in Olkiluoto (Western Finland) using bacterial and archaeal 16S rRNA, dsrB, and mcrA gene transcript targeted 454 pyrosequencing. Over a depth range of 296-798?m below ground surface the microbial communities changed according to depth, salinity gradient, and sulphate and methane concentrations. The highest bacterial diversity was observed in the sulphate-methane mixing zone (SMMZ) at 250-350?m depth, whereas archaeal diversity was highest in the lowest boundaries of the SMMZ. Sulphide-oxidizing e-proteobacteria (Sulfurimonas sp.) dominated in the SMMZ and ?-proteobacteria (Pseudomonas spp.) below the SMMZ. The active archaeal communities consisted mostly of ANME-2D and Thermoplasmatales groups, although Methermicoccaceae, Methanobacteriaceae, and Thermoplasmatales (SAGMEG, TMG) were more common at 415-559?m depth. Typical indicator microorganisms for sulphate-methane transition zones in marine sediments, such as ANME-1 archaea, a-, ß- and d-proteobacteria, JS1, Actinomycetes, Planctomycetes, Chloroflexi, and MBGB Crenarchaeota were detected at specific depths. DsrB genes were most numerous and most actively transcribed in the SMMZ while the mcrA gene concentration was highest in the deep methane rich groundwater. Our results demonstrate that active and highly diverse but sparse and stratified microbial communities inhabit the Fennoscandian deep bedrock ecosystems.
Notes
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PubMed ID
26425566 View in PubMed
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[Activity and structure of the sulfate-reducing bacterial community in the sediments of the southern part of Lake Baikal].

https://arctichealth.org/en/permalink/ahliterature259583
Source
Mikrobiologiia. 2014 Mar-Apr;83(2):180-90
Publication Type
Article
Author
N V Pimenov
E E Zakharova
A L Briukhanov
V A Korneeva
B B Kuznetsov
T P Turova
T V Pogodaeva
G V Kalmychkov
T I Zemskaia
Source
Mikrobiologiia. 2014 Mar-Apr;83(2):180-90
Language
Russian
Publication Type
Article
Keywords
DNA, Bacterial - genetics
Geologic Sediments - microbiology
Lakes - microbiology
Microbial Consortia - physiology
Molecular Sequence Data
Phylogeny
RNA, Ribosomal, 16S
Siberia
Sulfur-Reducing Bacteria - genetics - isolation & purification
Water Microbiology
Abstract
The rates of sulfate reduction (SR) and the diversity of sulfate-reducing bacteria (SRB) were studied in the sediments of the Posol'skaya banka elevation in the southern part of Lake Baikal. SR rates varied from 1.2 to 1641 nmol/(dm3 day), with high rates (> 600 nmol/(dm3 day)) observed at both deep-water stations and in subsurface silts. Integral SR rates calculated for the uppermost 50 cm of the sediments were higher for gas-saturated and gas hydrate-bearing sediments than in those with low methane content. Enrichment SRB cultures were obtained in Widdel medium for freshwater SRB. Analysis of the 16S rRNA gene fragments from clone libraries obtained from the enrichments revealed the presence of SRB belonged to Desulfosporosinus genus, with D. lacus as the most closely related member (capable of sulfate, sulfite, and thiosulfate reduction), as well as members of the order Clostridiales.
PubMed ID
25423722 View in PubMed
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Additive Models Reveal Sources of Metals and Organic Pollutants in Norwegian Marine Sediments.

https://arctichealth.org/en/permalink/ahliterature292349
Source
Environ Sci Technol. 2017 Nov 07; 51(21):12764-12773
Publication Type
Journal Article
Date
Nov-07-2017
Author
Gert Everaert
Anders Ruus
Dag Øystein Hjermann
Katrine Borgå
Norman Green
Stepan Boitsov
Henning Jensen
Amanda Poste
Author Affiliation
Department of Applied Ecology and Environmental Biology, Ghent University , 9000 Ghent, Belgium.
Source
Environ Sci Technol. 2017 Nov 07; 51(21):12764-12773
Date
Nov-07-2017
Language
English
Publication Type
Journal Article
Keywords
Environmental monitoring
Geologic sediments
Metals
North Sea
Norway
Polychlorinated Biphenyls
Polycyclic Aromatic Hydrocarbons
Water Pollutants, Chemical
Abstract
We characterized spatial patterns of surface sediment concentrations of seven polychlorinated biphenyls (PCBs), seven polycyclic aromatic hydrocarbons (PAHs), three chlorinated pesticides, and five metals in Norwegian waters and Skagerrak. In total, we analyzed 5036 concentrations of 22 chemical substances that were measured between 1986 and 2014 at 333 sampling sites by means of generalized additive models (GAMs). We found that GAMs with organic carbon content of the sediment and latitude and longitude as co-variates explained as ca. 75% of the variability of the contaminant sediment concentrations. For metals, a predominantly hotspot-driven spatial pattern was found, i.e., we identified historical pollution hotspots (e.g., Sørfjord in western Norway) for mercury, zinc, cadmium, and lead. Highest concentrations of PAHs and PCBs were found close to densely populated and industrialized regions, i.e., in the North Sea and in the Kattegat and Skagerrak. The spatial pattern of the PCBs suggests the secondary and diffuse atmospheric nature of their sources. Atmospheric inputs are the main sources of pollution for most organic chemicals considered, but north of the Arctic circle, we found that concentrations of PAHs increased from south to north most likely related to a combination of coal-eroding bedrock and the biological pump. The knowledge acquired in the present research is essential for developing effective remediation strategies that are consistent with international conventions on pollution control.
PubMed ID
29034678 View in PubMed
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Aerobic biodegradation of vinyl chloride and cis-1,2-dichloroethylene in aquifer sediments.

https://arctichealth.org/en/permalink/ahliterature83353
Source
Chemosphere. 2005 Sep;60(11):1555-64
Publication Type
Article
Date
Sep-2005
Author
Broholm Kim
Ludvigsen Liselotte
Jensen Thorkild Feldthusen
Østergaard Henrik
Author Affiliation
DHI--Institute for Water and Environment, HSW, Agern Alle 5, DK-2970 Hørsholm, Denmark. kib@dhi.dk
Source
Chemosphere. 2005 Sep;60(11):1555-64
Date
Sep-2005
Language
English
Publication Type
Article
Keywords
Aerobiosis
Biodegradation, Environmental
Dichloroethylenes - chemistry
Geologic Sediments - chemistry
Methane - chemistry
Oxygen - chemistry
Vinyl Chloride - chemistry
Abstract
Laboratory batch experiments have been performed with sediment and groundwater obtained from two sites in Denmark to study the aerobic biodegradation of vinyl chloride (VC) and cis-1,2-dichloroethylene (c-1,2-DCE) to assess the natural aerobic biodegradation potential at two sites. The experiments revealed that VC was degraded to below the detection limit within 204 and 57 days at the two sites. c-1,2-DCE was also degraded in the experiments but not completely. At the two sites 50% and 35% was removed by the end of the experimental period of 204 and 274 days. The removal of c-1,2-DCE seems to occur concomitantly with VC indicating that the biodegradation of c-1,2-DCE may depend on the biodegradation of VC. However, in both cases natural groundwater was mixed with sediment and consequently there may be other compounds (e.g. ammonium, natural organic compound etc.) that serves as primary substrates for the co-metabolic biodegradation of c-1,2-DCE. At one of the sites methane was supplied to try to enhance the biodegradation of VC and c-1,2-DCE. That was successful since the time for complete biodegradation of VC decreased from 204 days in the absence of methane to 84 days in the presence of methane. For c-1,2-DCE the amount that was biodegraded after 204 days increased from 50% to 90% as a result of the addition of methane. It seems like a potential for natural biodegradation exists at least for VC at these two sites and also to some degree for c-1,2-DCE.
PubMed ID
16083761 View in PubMed
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464 records – page 1 of 47.