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[Abundance and activity of microorganisms at the water-sediment interface and their effect on the carbon isotopic composition of suspended organic matter and sediments of the Kara Sea].

https://arctichealth.org/en/permalink/ahliterature259299
Source
Mikrobiologiia. 2013 Nov-Dec;82(6):723-31
Publication Type
Article
Author
M V Ivanov
A Iu Lein
A S Savvichev
I I Rusanov
E F Veslopolova
E E Zakharova
T S Prusakova
Source
Mikrobiologiia. 2013 Nov-Dec;82(6):723-31
Language
Russian
Publication Type
Article
Keywords
Arctic Regions
Carbon Isotopes - analysis - metabolism
Methanobacteriales - metabolism
Methanomicrobiales - metabolism
Oceans and Seas
Russia
Water Microbiology
Abstract
At ten stations of the meridian profile in the eastern Kara Sea from the Yenisei estuary through the shallow shelf and further through the St. Anna trough, total microbial numbers (TMN) determined by direct counting, total activity of the microbial community determined by dark CO2 assimilation (DCA), and the carbon isotopic composition of organic matter in suspension and upper sediment horizons (d13C, per thousand) were investigated. Three horizons were studied in detail: (1) the near-bottom water layer (20-30 cm above the sediment); (2) the uppermost, strongly hydrated sediment horizon, further termed warp (5-10 mm); and (3) the upper sediment horizon (1-5 cm). Due to decrease in the amount of isotopically light carbon of terrigenous origin with increasing distance from the Yenisei estuary, the TMN and DCA values decreased, and the d13C changed gradually from -29.7 to -23.9 per thousand. At most stations, a noticeable decrease in TMN and DCA values with depth was observed in the water column, while the carbon isotopic composition of suspended organic matter did not change significantly. Considerable changes of all parameters were detected in the interface zone: TMN and DCA increased in the sediments compared to their values in near-bottom water, while the 13C content increased significantly, with d13C of organic matter in the sediments being at some stations 3.5- 4.0 per thousand higher than in the near-bottom water. Due to insufficient illumination in the near-bottom zone, newly formed isotopically heavy organic matter (d13C(-) -20 per thousand) could not be formed by photosynthesis, active growth of chemoautotrophic microorganisms in this zone is suggested, which may use reduced sulfur, nitrogen, and carbon compounds diffusing from anaerobic sediments. High DCA values for the interface zone samples confirm this hypothesis. Moreover, neutrophilic sulfur-oxidizing bacteria were retrieved from the samples of this zone.
PubMed ID
25509411 View in PubMed
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Anthropogenic carbon as a basal resource in the benthic food webs in the Neva Estuary (Baltic Sea).

https://arctichealth.org/en/permalink/ahliterature310040
Source
Mar Pollut Bull. 2019 Sep; 146:190-200
Publication Type
Journal Article
Date
Sep-2019
Author
Sergey M Golubkov
Mikhail S Golubkov
Alexei V Tiunov
Author Affiliation
Zoological Institute of Russian Academy of Sciences, Universitetskaya emb. 1, Saint-Petersburg 199034, Russian Federation. Electronic address: golubkov@zin.ru.
Source
Mar Pollut Bull. 2019 Sep; 146:190-200
Date
Sep-2019
Language
English
Publication Type
Journal Article
Keywords
Animals
Bayes Theorem
Carbon - metabolism
Carbon Isotopes - analysis
Crustacea
Estuaries
Fishes
Food chain
Invertebrates
Models, Theoretical
Nitrogen Isotopes - analysis
Oceans and Seas
Phytoplankton
Russia
Waste Water - chemistry
Abstract
Organic pollution is a serious environmental problem for the coastal zones of seas. The study tested the hypothesis that allochthonous organic carbon derived from St. Petersburg wastewaters is a significant basal resource of carbon for the benthic food webs. We analyzed stable isotope composition of carbon and nitrogen in suspended organic matter in the Neva Estuary and in the tissues of macroinvertebrates and fish. The Stable Isotope Bayesian mixing model showed that waste waters were an important source of carbon for the most of consumers in the Neva Estuary. The autochthonous carbon produced by phytoplankton was a significant source of carbon only for some macroinvertebrates. The main consumers of the carbon derived from waste waters were tubificid worms, chironomid larvae and alien polychaete, which currently dominate in the zoobenthos of the estuary. These species replaced the former dominants, native crustaceans, which to a lesser extent use anthropogenic carbon.
PubMed ID
31426146 View in PubMed
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Arctic moistening provides negative feedbacks to riparian plants.

https://arctichealth.org/en/permalink/ahliterature296986
Source
Glob Chang Biol. 2018 06; 24(6):2691-2707
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
06-2018
Author
Samuli Helama
Laura Arppe
Kari Mielikäinen
Markku Oinonen
Author Affiliation
Natural Resources Institute Finland, Rovaniemi, Finland.
Source
Glob Chang Biol. 2018 06; 24(6):2691-2707
Date
06-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Arctic Regions
Biomass
Carbon - metabolism
Carbon Isotopes - analysis
Finland
Floods
Pinus sylvestris - growth & development - metabolism
Abstract
Arctic moistening will affect the circumpolar forested riparian ecosystems. Upward trends observed for precipitation in high latitudes illustrate that the moistening may be underway to influence the woody biomass production near the inland waters, lakes and streams with effects on carbon pools and fluxes. Although the flooding and waterlogging tolerance of seedlings has been investigated, our understanding of responses in mature trees is still limited. Here we employ tree-ring d13 C and width data from a subarctic riparian setting in Lapland, where artificially high lake level (HLL) has already altered the ecophysiological and growth responses of riparian Pinus sylvestris trees to external drivers under conditions simulating moister environment. Prior to the HLL event, the carbon assimilation rate was primarily limited by irradiance as reflected in the d13 C data and the radial growth of south-facing riparian trees remained increased in comparison to shaded upland trees. By contrast, the riparian trees were not similarly benefited during the HLL period when reduced assimilation depleted the riparian in comparison to upland d13 C despite of increased irradiance. As a result, the radial growth of riparian trees was markedly reduced over the HLL event while the upland trees benefited from increased irradiance and summer time warming. Although the production of biomass at high latitudes is commonly considered temperature-limited, our results highlight the increasing role of Arctic moistening to limit the growth when increased precipitation (cloudiness) reduces the incoming solar radiation in general and when the riparian habitat becomes increasingly waterlogged in particular. The effects of high-latitude warming to induce higher biomass productivity may be restricted by negative feedbacks.
PubMed ID
29436149 View in PubMed
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Are herbarium mosses reliable indicators of historical nitrogen deposition?

https://arctichealth.org/en/permalink/ahliterature289939
Source
Environ Pollut. 2017 Dec; 231(Pt 1):1201-1207
Publication Type
Journal Article
Date
Dec-2017
Author
Tora Finderup Nielsen
Jesper Ruf Larsen
Anders Michelsen
Hans Henrik Bruun
Author Affiliation
Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark. Electronic address: tora.nielsen@bio.ku.dk.
Source
Environ Pollut. 2017 Dec; 231(Pt 1):1201-1207
Date
Dec-2017
Language
English
Publication Type
Journal Article
Keywords
Bryophyta - chemistry
Carbon Isotopes - analysis
Denmark
Environmental Monitoring - methods
Environmental pollution - analysis
Lead - analysis
Magnesium - analysis
Nitrogen - analysis
Nitrogen Isotopes - analysis
Time Factors
Abstract
Mosses collected decades ago and stored in herbaria are often used to assess historical nitrogen deposition. This method is effectively based on the assumption that tissue N concentration remains constant during storage. The present study raises serious doubt about the generality of that assumption. We measured tissue N and C concentrations as well as d15N, d13C, Pb and Mg in herbarium and present day samples of seven bryophyte species from six sites across Denmark. While an increase in nitrogen deposition during the last century is well-documented for the study site, we surprisingly found foliar N concentration to be higher in historical samples than in modern samples. Based on d15N values and Pb concentration, we find nitrogen contamination of herbarium specimens during storage to be the most likely cause, possibly in combination with dilution though growth and/or decomposition during storage. We suggest ways to assess contamination and recommend caution to be taken when using herbarium specimens to assess historical pollution if exposure during storage cannot be ruled out.
PubMed ID
28420490 View in PubMed
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Baleen as a biomonitor of mercury content and dietary history of North Atlantic minke whales (Balaenopetra acutorostrata): combining elemental and stable isotope approaches.

https://arctichealth.org/en/permalink/ahliterature61529
Source
Sci Total Environ. 2004 Sep 20;331(1-3):69-82
Publication Type
Article
Date
Sep-20-2004
Author
K A Hobson
F F Riget
P M Outridge
R. Dietz
E. Born
Author Affiliation
Prairie and Northern Wildlife Research Center, Canadian Wildlife Service, 115 Perimeter Road, Saskatoon, SK, S7 N 0X4, Canada.
Source
Sci Total Environ. 2004 Sep 20;331(1-3):69-82
Date
Sep-20-2004
Language
English
Publication Type
Article
Keywords
Animals
Atlantic Ocean
Carbon Isotopes - analysis
Diet
Environmental Monitoring - methods
Female
Greenland
Male
Mercury - analysis - pharmacokinetics
Nitrogen Isotopes - analysis
Research Support, Non-U.S. Gov't
Tissue Distribution
Water Pollutants - analysis - pharmacokinetics
Whales - physiology
Abstract
Baleen is an incrementally-growing tissue of balaenopteran whales which preserves relatively well over time in museums and some archeological sites, and, therefore might be useful for studies examining long-term changes of metal levels in whales. This study examined Hg and stable C and N isotopic composition of baleen plates of the North Atlantic minke whale (Balaenoptera acutorostrata), which continues to be a food source for people in Greenland and elsewhere. We compared the Hg levels and stable isotopes of major tissues (kidney, liver and muscle) with those of baleen plates to see whether baleen could be used as a biomonitor of variations of Hg intake and diet both between individuals and within individuals over time. Mercury was significantly correlated with concentrations in all tissues (kidney, liver and muscle). Stable C and N isotopes in baleen were generally similar to those of muscle, which reflects the recent (approximately one month) feeding of the whale, but in some individuals there were significant differences between baleen and muscle. Sectioning of baleen into 1 cm longitudinal increments showed that these differences were due to marked dietary shifts by some individuals over time that had been recorded in the baleen but were lost from the muscle record. Whole baleen C and N isotopes were better correlated with tissue Hg levels, suggesting that baleen may provide a more reliable indicator of long-term average diet, which in turn may be better related to Hg accumulation in tissues than the shorter-term diet record contained in muscle.
PubMed ID
15325142 View in PubMed
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Bayesian stable isotope mixing models effectively characterize the diet of an Arctic raptor.

https://arctichealth.org/en/permalink/ahliterature311539
Source
J Anim Ecol. 2020 12; 89(12):2972-2985
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
12-2020
Author
Devin L Johnson
Michael T Henderson
David L Anderson
Travis L Booms
Cory T Williams
Author Affiliation
Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA.
Source
J Anim Ecol. 2020 12; 89(12):2972-2985
Date
12-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Arctic Regions
Bayes Theorem
Carbon Isotopes - analysis
Diet - veterinary
Food chain
Nitrogen Isotopes - analysis
Raptors
Abstract
Bayesian stable isotope mixing models (BSIMMs) for d13 C and d15 N can be a useful tool to reconstruct diets, characterize trophic relationships, and assess spatiotemporal variation in food webs. However, use of this approach typically requires a priori knowledge on the level of enrichment occurring between the diet and tissue of the consumer being sampled (i.e. a trophic discrimination factor or TDF). Trophic discrimination factors derived from captive feeding studies are highly variable, and it is challenging to select the appropriate TDF for diet estimation in wild populations. We introduce a novel method for estimating TDFs in a wild population-a proportionally balanced equation that uses high-precision diet estimates from nest cameras installed on a subset of nests in lieu of a controlled feeding study (TDFCAM ). We tested the ability of BSIMMs to characterize diet in a free-living population of gyrfalcon Falco rusticolus nestlings by comparing model output to high-precision nest camera diet estimates. We analysed the performance of models formulated with a TDFCAM against other relevant TDFs and assessed model sensitivity to an informative prior. We applied the most parsimonious model inputs to a larger sample to analyse broad-scale temporal dietary trends. Bayesian stable isotope mixing models fitted with a TDFCAM and uninformative prior had the best agreement with nest camera data, outperforming TDFs derived from captive feeding studies. BSIMMs produced with a TDFCAM produced reliable diet estimates at the nest level and accurately identified significant temporal shifts in gyrfalcon diet within and between years. Our method of TDF estimation produced more accurate estimates of TDFs in a wild population than traditional approaches, consequently improving BSIMM diet estimates. We demonstrate how BSIMMs can complement a high-precision diet study by expanding its spatiotemporal scope of inference and recommend this integrative methodology as a powerful tool for future trophic studies.
PubMed ID
33020919 View in PubMed
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Carbon-13 urea breath test for Helicobacter pylori infection in patients with uninvestigated ulcer-like dyspepsia: an evidence-based analysis.

https://arctichealth.org/en/permalink/ahliterature106170
Source
Ont Health Technol Assess Ser. 2013;13(19):1-30
Publication Type
Article
Date
2013
Author
D. Ling
Source
Ont Health Technol Assess Ser. 2013;13(19):1-30
Date
2013
Language
English
Publication Type
Article
Keywords
Adult
Breath Tests - methods
Carbon Isotopes - analysis
Dyspepsia - diagnosis - etiology - microbiology
Female
Helicobacter Infections - complications - diagnosis - microbiology
Helicobacter pylori - immunology - isolation & purification - metabolism
Humans
Male
Ontario - epidemiology
Sensitivity and specificity
Urea - analysis - diagnostic use
Abstract
Dyspepsia is a condition defined by chronic pain or discomfort in the upper gastrointestinal tract that can be caused by Helicobacter pylori. The carbon-13 urea breath test (¹³C UBT) is a non-invasive test to detect H. pylori.
We aimed to determine the diagnostic accuracy and clinical utility of the ¹³C UBT in adult patients with ulcer-like dyspepsia who have no alarm features.
A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2003 and 2012.
We abstracted the sensitivity and specificity, which were calculated against a composite reference standard. Summary estimates were obtained using bivariate random effects regression analysis.
From 19 diagnostic studies, the ¹³C UBT summary estimates were 98.1% (95% confidence interval [CI], 96.3-99.0) for sensitivity and 95.1% (95% CI, 90.3-97.6) for specificity. In 6 studies that compared the ¹³C UBT with serology, the 1¹³C UBT sensitivity was 95.0% (95% CI, 90.1-97.5) and specificity was 91.6 % (95% CI, 81.3-96.4). The sensitivity and specificity for serology were 92.9% (95% CI, 82.6-97.3) and 71.1% (95% CI, 63.8-77.5), respectively. In 1 RCT, symptom resolution, medication use, and physician visits were similar among the ¹³C UBT, serology, gastroscopy, or empirical treatment arms. However, patients tested with ¹³C UBT reported higher dyspepsia-specific quality of life scores.
Processing of the ¹³C UBT results can vary according to many factors. Further, the studies showed significant heterogeneity and used different composite reference standards.
The ¹³C UBT is an accurate test with high sensitivity and specificity. Compared with serology, it has higher specificity. There is a paucity of data on the ¹³C UBT beyond test accuracy.
Breath test for detecting bacteria in patients with ulcer-like symptoms. Dyspepsia is a condition that causes long-term pain or discomfort in the upper abdomen. Symptoms can include heartburn, burping, bloating, nausea, or slow digestion. Dyspepsia can be caused by a bacterium that also causes ulcers and stomach cancer. Half of the world's people are believed to be infected with these bacteria. A test has been developed to detect the bacteria in a breath sample. Our review determined the accuracy of this breath test in adults with ulcer-like symptoms. From 19 studies, the breath test correctly identified 98% of patients with the bacteria and 95% of patients without the bacteria, as determined by a reference standard. Six studies compared the breath test to a blood test that is currently used. Both the breath and blood tests performed well in correctly identifying patients with the bacteria. However, the blood test was incorrectly positive in 20 more patients who did not have the bacteria according to the breath test. This means that more patients would have received unnecessary treatment. Thus, the breath test is an accurate test to detect the bacteria in adult patients who have ulcer-like symptoms. But the many differences among the studies in our review included several steps taken to perform the breath test and the reference standards used to compare a blood test with the breath test.
Notes
Cites: CMAJ. 2000 Jun 13;162(12 Suppl):S3-2310870511
Cites: Aliment Pharmacol Ther. 2003 Jan;17(2):253-712534410
Cites: Aliment Pharmacol Ther. 2003 Mar 15;17(6):793-812641501
Cites: Rev Esp Enferm Dig. 2003 Feb;95(2):121-6, 115-2012760719
Cites: Aliment Pharmacol Ther. 2003 Jun 15;17(12):1481-9112823150
Cites: J Gastroenterol Hepatol. 2003 Nov;18(11):1237-4314535979
Cites: Dig Liver Dis. 2003 Sep;35(9):612-814563182
Cites: Lancet. 2006 Jun 17;367(9527):1990-616782489
Cites: BMC Med Res Methodol. 2006;6:3116836745
Cites: J Coll Physicians Surg Pak. 2007 Feb;17(2):84-817288853
Cites: Can J Gastroenterol. 2007 Aug;21(8):501-617703249
Cites: Med Princ Pract. 2009;18(1):57-6119060493
Cites: Clin Infect Dis. 2009 May 15;48(10):1385-9119368506
Cites: J Gastroenterol Hepatol. 2009 Oct;24(10):1587-60019788600
Cites: J Clin Epidemiol. 2011 Apr;64(4):380-221185693
Cites: World J Gastroenterol. 2011 Nov 14;17(42):4682-822180710
Cites: Gut. 2012 May;61(5):646-6422491499
Cites: FEMS Immunol Med Microbiol. 2012 Apr;64(3):352-6322141752
Cites: Gastroenterology. 2005 Nov;129(5):1753-516285970
Cites: World J Gastroenterol. 2005 Sep 21;11(35):5545-816222752
Cites: J Clin Epidemiol. 2005 Oct;58(10):982-9016168343
Cites: Dig Liver Dis. 2005 Oct;37(10):751-516023902
Cites: Int J Clin Pract. 2005 Feb;59(2):194-20115854196
Cites: World J Gastroenterol. 2005 Mar 7;11(9):1361-415761976
Cites: Aliment Pharmacol Ther. 2004 Nov 15;20(10):1001-1715569102
Cites: Am J Gastroenterol. 1999 Oct;94(10):2845-5410520832
Cites: Ital J Gastroenterol Hepatol. 1998 Oct;30 Suppl 3:S315-910077764
Cites: Aliment Pharmacol Ther. 2003 Nov 1;18(9):927-3114616156
Cites: J Gastroenterol. 2004 Jul;39(7):621-815293131
Cites: J Gastroenterol. 2004 Jul;39(7):629-3415293132
Cites: Can J Gastroenterol. 2004 Sep;18(9):547-5415457293
Cites: Dig Liver Dis. 2004 Oct;36(10):661-515506664
Cites: Med Decis Making. 1993 Oct-Dec;13(4):313-218246704
Cites: Int J Technol Assess Health Care. 1994 Fall;10(4):714-57843894
Cites: Can J Gastroenterol. 1998 Jan-Feb;12(1):31-419544410
Cites: Gastroenterology. 1997 Dec;113(6 Suppl):S9-149394753
Cites: J Lab Clin Med. 2006 Mar;147(3):145-916503245
PubMed ID
24228082 View in PubMed
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[Carbon Isotope Composition in Landscape Components and Its Changes under Different Ecological Conditions].

https://arctichealth.org/en/permalink/ahliterature274565
Source
Izv Akad Nauk Ser Biol. 2016 Mar-Apr;(2):216-24
Publication Type
Article
Author
I V Kovda
E G Morgun
K B Gongalskii
S A Balandin
A I Erokhina
Source
Izv Akad Nauk Ser Biol. 2016 Mar-Apr;(2):216-24
Language
Russian
Publication Type
Article
Keywords
Carbon Isotopes - analysis
Ecosystem
Plants - chemistry
Russia
Soil - chemistry
Abstract
The composition of stable carbon isotopes in plants, plant litter, leaf litter, and soil organic matter was studied experimentally in the western part of the northern foothills of the Caucasus and mountainsides. It was found that the changes in carbon isotope composition depending on the vertical zonation do not exceed 8 per thousand and depend on the type of C3 plant communities, its presence in biogeocenosis components (living matter, plant litter, soil organic matter), and the degree of moistening of the plot studied.
PubMed ID
27396183 View in PubMed
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Carbon isotope ratios of nandrolone, boldenone, and testosterone preparations seized in Norway compared to those of endogenously produced steroids in a Nordic reference population.

https://arctichealth.org/en/permalink/ahliterature265575
Source
Drug Test Anal. 2014 Nov-Dec;6(11-12):1163-9
Publication Type
Article
Author
Ingunn Hullstein
Carlos Sagredo
Peter Hemmersbach
Source
Drug Test Anal. 2014 Nov-Dec;6(11-12):1163-9
Language
English
Publication Type
Article
Keywords
Anabolic Agents - analysis
Carbon Isotopes - analysis
Denmark
Esters - analysis - urine
Female
Gas Chromatography-Mass Spectrometry
Humans
Male
Nandrolone - analysis
Norway
Reference Standards
Solutions
Testosterone - analogs & derivatives - analysis
Young Adult
Abstract
Determining the origin of anabolic androgenic steroids (AAS) that also are produced endogenously in the human body is a major issue in doping control. In some cases, the presence of nandrolone and boldenone metabolites might result from endogenous production. The GC-C-IRMS technique (gas chromatography-combustion-isotope ratio mass spectrometry) enables the carbon isotopic ratio (CIR) to be measured to determine the origin of these metabolites. The aim of this study was to use GC-C-IRMS to determine the d(13) CVPDB values of seized boldenone and nandrolone preparations to decide if the steroids themselves were depleted in (13) C, compared to what is normally seen in endogenously produced steroids. In addition, several testosterone preparations were analyzed. A total of 69 seized preparations were analyzed. The nandrolone preparations showed d(13) CVPDB values in the range of -31.5 ‰ to -26.7 ‰. The boldenone preparations showed d(13) CVPDB values in the range of -32.0 ‰ to -27.8 ‰, and for comparison the testosterone preparations showed d(13) CVPDB values of -31.0 ‰ to -24.2 ‰. The results showed that the values measured in the nandrolone and boldenone preparations were in the same range as those measured in the testosterone preparations. The study also included measurements of CIR of endogenously produced steroids in a Norwegian/Danish reference population. The d(13) CVPDB values measured for the endogenous steroids in this population were in the range of -21.7 to -26.8. In general, most of the preparations investigated in this study show (13) C-depleted delta values compared to endogenously produced steroids reflecting a northern European diet.
PubMed ID
25388436 View in PubMed
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Compilation and review of 87Sr/86Sr and stable isotopes from groundwater, calcite fracture fillings, mineral, and whole-rock sampling at Äspö, Sweden.

https://arctichealth.org/en/permalink/ahliterature269933
Source
Ground Water. 2015 Apr;53 Suppl 1:103-12
Publication Type
Article
Date
Apr-2015
Author
Bill Wallin
Zell Peterman
Source
Ground Water. 2015 Apr;53 Suppl 1:103-12
Date
Apr-2015
Language
English
Publication Type
Article
Keywords
Calcium Carbonate - chemistry
Carbon Isotopes - analysis
Environmental Monitoring - methods
Geologic Sediments - chemistry
Groundwater - analysis - chemistry
Minerals - chemistry
Oxygen Isotopes - analysis
Salinity
Seawater - chemistry
Strontium isotopes - analysis
Sweden
Abstract
Integrated isotopic and hydrochemical studies of groundwater at Äspö, Sweden, support mixing models involving deep saline water, low-solute infiltration, and Baltic Sea water. Carbon, oxygen, and strontium isotope analyses of calcite fracture fillings indicate that paleohydrologic conditions were different than those of today in terms of the isotopic composition of water flowing through fractures. Sr isotopes of whole-rock and mineral (plagioclase, microcline, biotite, and epidote) samples are used to assess the effects of water-rock interaction. Biotite is a major reactant in the early stages of water-rock interaction. Strontium isotope systematics of groundwater from deep in the Hard Rock Laboratory, and underground research facility, and from low conductivity zones revealed a first order mixing line defined by a high-chloride saline component with 66?mg/L Sr and an ancient sea water component with approximately 4.5?mg/L. Dilution with low salinity recharge has produced groundwater with variable Sr contents and 87Sr/86Sr values between 0.7186 and 0.7160. Differences between Äspö and Laxemar groundwater are shown by trends in Sr concentrations plotted against 87Sr/86Sr. The Äspö trend shows increasing 87Sr/86Sr values with increasing concentrations of Sr, whereas the Laxemar groundwater trend shows little variability in 87Sr/86Sr with increasing Sr concentrations. These trends are controlled by the differences in 87Sr/86Sr composition of the saline end members in the two areas.
PubMed ID
24571642 View in PubMed
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56 records – page 1 of 6.