Wszystkie pola: C isotope - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Sulphate reduction - methane oxidation: a potential role of this process in the origin of C isotope environmental record in freshwater carbonates
Autorzy:: Jędrysek, M. O.
Powiązania:: https://bibliotekanauki.pl/articles/1186076.pdf
Data publikacji:: 2005
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: woda słodka
węgiel
tlen
siarka
metan
węglany
siarczany
izotopy
antropopresja
fresh water
carbon
oxygen
sulphur
methane
carbonates
sulphates
isotopes
anthropogenic impact
Opis:: W pracy wykazano, że węglany jeziorne powstałe w wyniku mikrobiologicznego utleniania związków organicznych (w tym metanu), przy redukcji jonów siarczanowych, mogą stanowić ważny geochemiczny zapis zmian środowiskowych. Najprawdopodobniej niskie wartości 13C w kalcycie, w rzekach i jeziorach eutroficznych wynikają z silnego utleniania związków organicznych w warunkach turbulencji i/lub podwyższonych stężeń siarczanu. Podobnie, wysokie wartości 13C w kalcycie, zawartym w osadach słodkowodnych bogatych w materię organiczną, mogą wskazywać na niski potencjał redox. Na podstawie tego typu badania wydaje się możliwe wykalibrowanie nowego narzędzia do rekonstrukcji palaeośrodowiskowych. Z drugiej strony, utlenianie metanu (związków organicznych) może powodować wzbogacenie rezydualnego jonu siarczanowego w ciężkie izotopy tlenu i siarki. Dlatego, aby lepiej zrozumieć sygnał izotopowy w węglanach jeziornych, wykonano badania stężenia i badania izotopowe siarczanu kolumny wodnej oraz badania metanu i kalcytu w osadach 24 jezior, 2 stawów i 4 rzek w Polsce. Rozpuszczony jon siarczanowy jest jednym z głównych składników rozpuszczonych w wodach jeziornych, a siarka, jako istotny biopierwiastek, wpływa na procesy zachodzące w jeziorach, w tym na jakość wód (mikrobiologiczny rozkład związków organicznych, inhibitor metanogenezy). Najwyższe stężenie jonu siarczanowego stwierdzono w rzekach (85,47 ncentration of sulphate has been detected in rivers (85.47 SO42- mg/l) i sztucznym jeziorze (70,3 SO42 -42- mg/l) w regionie silnego zanieczyszczenia (tzw. "Czarny Trójkąt") w Polsce południowo-zachodniej. Najniższe stężenie siarczanu stwierdzono w jeziorach dystroficznych i oligotroficznych - górskich (od 0,5 do 3 mg/l SOSO42 -). Najniższe wartości δ34S(SO42-) i δ18O(SO42-) występują w niezanieczyszczonych jeziorach wschodniej Polski (-0,94 i 1,38‰). Najwyższe wartości δ34S(SO42-) i δ18O(SO42-) stwierdzono w Polsce zachodniej i jeziorach dystroficznych (12,95 i 16,15‰). Wykazano, że. δ34S(SO42- i δ18O(SO42-) jezior mogą być dobrym narzędziem do ilościowej charakterystyki antropopresji (kwaśne opady) oraz do monitorowania zmian trofii i procesów redoks związanych z biodegradacją związków organicznych w osadach i kolumnie wodnej. W przeciwieństwie do czystych jezior, jeziora silnie zanieczyszczone jonem siarczanowym wykazują wzrost wartościδ13C(CH4) wraz ze wzrostem głębokości kolumny wodnej. Może to być wskaźnikiem utraty przez jezioro mikrobiologicznej zdolności buforującej.
Źródło:: Polish Geological Institute Special Papers; 2005, 16; 18--34
1507-9791
Pojawia się w:: Polish Geological Institute Special Papers
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Carbon-13 in alpha-cellulose of oak latewood (Jędrzejów, Southern Poland) during the Maunder Minimum
Autorzy:: Pazdur, A.
Korput, S.
Fogtman, M.
Szczepanek, M.
Hałas, S.
Krąpiec, M.
Szychowska-Krąpiec, E.
Powiązania:: https://bibliotekanauki.pl/articles/2058897.pdf
Data publikacji:: 2005
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: 13C isotope
alpha-cellulose
Maunder Minimum
tree-rings
Opis:: We have studied the δ13C signature in latewood alpha-cellulose of an ancient oak (Quercus robur L.) from a Cisterian Abbey belfry in Jędrzejów (Southern Poland). The time scale for the delta 13C record during 1631-1765 AD was built on the basis of detailed dendrochronology studies. Techniques available for extraction of alpha-cellulose from small samples have been used, the mean value of alpha-cellulose extraction efficiency being ca. 35%. In the delta 13C record of alpha-cellulose the cooling between 1650-1700 AD is clearly visible as a decrease of about 1.5‰. This period is consistent with the interval of the lowest solaractivity between 1645 and 1715 AD, which is known as the Maunder Minimum. Anti-correlation between δ13C and δ13C during the Maunder Minimum was observed but δ13C record is delayed by about 30 years with respect to the Maunder Minimum.
Źródło:: Geological Quarterly; 2005, 49, 2; 165-172
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: NMR studies of human cystatin C - stable isotope labeling of human cystatin C
Autorzy:: Jurczak, P.
Maszota-Zieleniak, M.
Powiązania:: https://bibliotekanauki.pl/articles/1935821.pdf
Data publikacji:: 2014
Wydawca:: Politechnika Gdańska
Tematy:: NMR
overproduction
stable isotopes
proteins
labeling
nadprodukcja
stabilne izotopy
białka
etykietowanie
Opis:: The objective of this study was to obtain a double and triple labeled human cystatin C (hCC). Another objective was to record sets of 2D and 3D NMR spectra of the hCC dimer (in a solution) using a 700MHz spectrometer. The data obtained during attempts to determine the NMR structure should provide useful information about chemical shifts of amino acid residues. They will certainly accelerate solving the human cystatin C NMR structure. In this paper the main focus is put on triple isotopic labeling, protein overproduction and NMR analysis of hCC. The first two processes lead to obtaining hCC labeled with stable isotopes of carbon ( 13 C), nitrogen ( 15 N) and hydrogen ( 2 H) (double labeled hCC was obtained with a similar method). The obtained protein was later used for the purpose of NMR spectra.
Źródło:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 4; 327--330
1428-6394
Pojawia się w:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Biostratigraphy, geochemistry and sedimentology of Middle to Late Jurassic strata in the Strážovce section (Strážovské vrchy Mts), Krížna Nappe of the Central Carpathians, Slovakia
Autorzy:: Michalík, J.
Bąk, M.
Lintnerová, O.
Méres, Š
Powiązania:: https://bibliotekanauki.pl/articles/2060972.pdf
Data publikacji:: 2017
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Oxfordian
Kimmeridgian
C isotope
O isotope
REE
radiolarians
basinal collapse
Zliechov Basin
Fatric Unit
Oksford
izotop C
iIzotop O
radiolarie
Opis:: The Jurassic / Lower Cretaceous sequence of the Strážovce section has been deposited in the central, axial part of the Zliechov Basin. Its most characteristic part – the Ždiar Formation consists of bedded siliceous radiolarian limestones and radiolarites. The radiolar¬ian assemblage typical of the North Tethyan Bioprovince lived during mid Oxfordian – Early Kimmeridgian in a warm upper part of the well stratified water column, partially near to the thermocline. Radiolarian abundance decreases upwards. Productivity decrease is quanti¬fied by the share of biogenic SiO2 as well as by high EFSi values during sedimentation of both the Ždiar and Jasenina formations. The geochemical data indicate relatively stable volume of the siliciclastic component of the rocks and a felsic character comparable to the Average Shale. The chemically homogeneous sedimentary signal indicates values of both CPA and EF ≤ 1 of Ti, Zr, Fe, Na, K, Rb, V and U. The values of EF > 1 signal enrichment of elements with affinity to carbonate minerals (Sr, Mn, P, Y, and Mg). Metal enrichment (Cu, Zn and Ni) indicates metal mobilization from other sources or due to carbonate diagenesis. In comparison to the Average Shale, decreased ΣREE´s and negative Cech and Euch anomalies could be regarded as a typical deep sea water signal. The differentiated REE record of higher calcareous beds of the Jasenina Fm. suggests basinal dysoxic conditions. The “bell-shape” of curves (normalized to shale) indicate that REEs were slightly affected by carbonate diagenesis. The Oxfordian / Kimmeridgian siliceous sedimentation in the Zliechov Basin was influenced probably more by monsoon-controlled input of land derived weathered material than by hydrothermal fluids from the bottom rifts.
Źródło:: Volumina Jurassica; 2017, 15, 1; 161--178
1896-7876
1731-3708
Pojawia się w:: Volumina Jurassica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Carbon isotope effects in the studies of the mechanism of action of tyrosine phenol-lyase
Autorzy:: Augustyniak, W.
Kański, R.
Kańska, M.
Powiązania:: https://bibliotekanauki.pl/articles/148527.pdf
Data publikacji:: 2006
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: 12C/14C kinetic isotope effects
tyrosine phenol-lyase
Opis:: 12C/14C kinetic isotope effects on the hydrolytic cleavage of tyrosine to phenol and ammonium pyruvate catalyzed by Citrobacter freundii tyrosine phenol-lyase have been determined in positions 2, 3 and ring-1' of L-tyrosine. The competitive method with dual-label approach was applied with 3',5'-ring 3H as remote label. The results revealed the change of the effect on carbon atom in position 2 during the reaction course from the high normal values to low inverse values. On the other hand, the effect values on 3 and ring-1' position remained constant during the reaction course. The discussion of these results regarding the reaction mechanism is presented.
Źródło:: Nukleonika; 2006, 51,suppl.2; 7-11
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Ageing of organic matter in incubated freshwater sediments; in fer ences from C and H isotope ratios of methane
Autorzy:: Szynkiewicz, A.
Modelska, A.
Jedrysek, M-O.
Kurasiewicz, M.
Mastalerz, M.
Powiązania:: https://bibliotekanauki.pl/articles/2059090.pdf
Data publikacji:: 2008
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: methanogenic pathways
carbon and hydrogen isotopes
incubation
freshwater sediments
Opis:: The freshwater sediments were incubated under anaerobic conditions for 570 and 879 days to in vestigate the potential variations in methanogenic pathways due to increasing sediment age and recalcitrance of organic matter. The methanogenic pathways did not shift from acetate fermentation toward CO2 reduction, as indicated by the observed variations of the isotopic composition of methane in natural conditions. It appeared, however, that the observed decrease of methane concentration (from 86 to 39%) and continuous in crease in d13C(CH4) (from –69.7 to –59.0‰) and dD(CH4) values (from –381 to –320‰) resulted mainly from exhaustion of at least one methanogenic substratein the incubated sediments. To better understand processes controlling the variations of delta exp.13C(CH4) and deltaD(CH4) values relative to ageing of organic matter, the method of principal component analysis (PCA) was used. This method offers good comparison of the relation ships between variables when a larger number of parameters control a given process in the same time period. In this study, the PCA indicated three distinctive factors that controlled decomposition of organic matter during the incubation. Factor 1 explained 33% of observed variations among the variables and had positive (0.93–0.92) loadings for electric conductivity and DIC concentration and negative loading for delta exp.13C(CH4) val ues (–0.72). Factor 2 accounted for 28% and had high posi ive loading for deltaD(CH4) value (0.86) and high negative loading for methane concentration (–0.81). Factor 3 accounted for 19% and exhibited high positive loadings for temperature (0.90) and delta exp.13C(DIC) value (0.69). Factors 1 and 2 were directly linked to the methanogenesis and indicated that bigger accumulation of bio-products in sediments is likely important for variations of delta exp.3C and deltaD of methane. This study shows that method of principal component analysis might be a useful tool while studying biogeochemical carboncy cleduring early digenesis of freshwater sediments.
Źródło:: Geological Quarterly; 2008, 52, 4; 383-383
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Intrinsic deuterium isotope effects on NMR chemical shifts of hydrogen bonded systems
Autorzy:: Hansen, P.
Powiązania:: https://bibliotekanauki.pl/articles/146965.pdf
Data publikacji:: 2002
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: C-H hydrogen bonds
deuterium isotope effects
intramolecular hydrogen bonds
intrinsic isotope effects
nuclear shielding
steric effects
Opis:: This mini review describes intrinsic deuterium isotope effects on 13C chemical shifts of rigid hydrogen bonded compounds primarily in solution. The steric effects of intramolecularly hydrogen bonded compounds are dissected into different bond interactions leading either to steric compression or to steric twist. One-bond isotope effects involving CH(D) bonds are analyzed in terms of substituent effects and the question is raised whether isotope effects can be useful in the study of CHhydrogen bonds.
Źródło:: Nukleonika; 2002, 47,suppl.1; 37-42
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Faunal dynamics across the Silurian-Devonian positive isotope excursions (delta13C, delta18O) in Podolia, Ukraine: Comparative analysis of the Ireviken and Klonk events
Autorzy:: Racki, G.
Balinski, A.
Wrona, R.
Malkowski, K.
Drygant, D.
Szaniawski, H.
Powiązania:: https://bibliotekanauki.pl/articles/20924.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: fauna dynamics
Silurian
Devonian
isotope excursion
Podolia
Ukraine
comparative analysis
Ireviken event
Klonk event
Brachiopoda
Conodonta
Chitinozoa
carbon isotope
oxygen isotope
geochemistry
Opis:: Two global isotopic events, the early Sheinwoodian (early Wenlock) and that at the Silurian–Devonian transition, have been comprehensively studied in representative carbonate successions at Kytayhorod and Dnistrove, respectively, in Podolia, Ukraine, to compare geochemistry and biotic changes related correspondingly to the Ireviken and Klonk events. These two large−scale isotope excursions reveal different regional ecosystem tendencies. The well−defined increasing trend across the Llandovery–Wenlock boundary in siliciclastic input, redox states and, supposedly, bioproductivity, was without strict correlative relations to the major ¹³C enrichment event. The environmental and biotic evolution was forced by eustatic sea−level fluctuations and two−step climate change toward a glaciation episode, but strongly modified by regional epeirogeny movements due to location near the mobile Teisseyre−Törnquist Fault Zone. Thus, the global early Sheinwoodian biogeochemical perturbation was of minor depositional significance in this epeiric sea, as in many other Laurussian domains. Conversely, the Podolian sedimentary record of the Klonk Event exhibits temporal links to the abrupt δ¹³C anomaly, overprinted by a tectonically driven deepening pulse in the crucial S–D boundary interval. This carbon cycling turnover was reflected in the regional carbonate crisis and cooling episodes, paired with a tendency towards eutrophication and recurrent oxygen deficiency, but also with major storms and possible upwelling. Faunal responses in both Podolian sections follow some characters of the Silurian pattern worldwide, as manifested by conodont changeover prior to the major early Sheinwoodian isotopic/climatic anomaly. This contrasts with the relative brachiopod and chitinozoan resistances in the course of the Ireviken Event. Also, during the Klonk Event, a moderate faunal turnover, both in benthic and pelagic groups, occurred only near the very beginning of the prolonged ¹³C−enriched timespan across the system boundary, possibly due to progressive dysoxia and temperature drop. The characters point to a peculiarity of the Klonk Event by comparison with the Silurian global events, and some similarity already to the succeeding Devonian transgressive/anoxic episodes.
Źródło:: Acta Palaeontologica Polonica; 2012, 57, 4
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Isotope Effect of Disordered Superconductors
Autorzy:: Mierzyńska, M.
Wysokiński, K. I.
Powiązania:: https://bibliotekanauki.pl/articles/2038392.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Bt
74.62.-c
74.62.Dh
Opis:: The isotope effects in disordered weak and strong coupling superconductors of different symmetries of the order parameter have been studied. We have found that even though weak localisation corrections to Eliashberg equations describe a strong degradation of transition temperature with disorder of s-wave superconductors, their influence on isotope coefficient is relatively weak. On the other hand the calculated change of relative isotope coefficient with T$\text{}_{c}$/T$\text{}_{c0}$ in homogeneous thin film materials is similar to that observed in high temperature superconductors.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 647-652
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Note on the stable isotope values of vein calcite in the El-Seboah peralkaline granite (SW Egypt)
Autorzy:: Hassan, K. M.
Powiązania:: https://bibliotekanauki.pl/articles/2086543.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: δ13C
δ18O
carbonate-hosting veins
peralkaline granite
Egypt
Opis:: Stable isotope data for carbon (δ13C) and oxygen (δ18O) are used to constrain the environments of calcite formation in two veins in the El-Seboah peralkaline granite in south-western Egypt. Vein I with calcitemagnetite-goethite-hematite-quartz, and vein II with calcite-magnetite-goethite-kaolinite-hematite-quartz are texturally distinct. The calcite of each vein has characteristic δ13C- and δ18O-values: + 0.32 and -7.28‰ for vein I and + 1.16 and - 1.21‰ for vein II, respectively. The observed differences between the δ13C values of the two veins indicate that they represent two separate systems of primary dissolved inorganic carbon formed at or near equilibrium with atmospheric CO2. The δ18O values, on the other hand, indicate calcite deposition from meteoric waters which were fresh for vein I and brackish for vein II.
Źródło:: Mineralogia; 2011, 42, 2/3; 113--120
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Calcite cements and the stratigraphical significance of the marine [delta^13]C carbonate reference curve for the Upper Cretaceous Chalk of England
Autorzy:: Jeans, C.
Hu, X.
Mortimore, R.
Powiązania:: https://bibliotekanauki.pl/articles/139078.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: cement kalcytowy
chemostratygrafia
izotopy
korelacja
kreda
krzywa referencyjna
ograniczenia
calcite cement
chemostratigraphy
correlation
Cretaceous
[delta^13]C reference curve
isotope events
limitations
Opis:: The hypothesis of Jarvis et al. (2006) that a [delta^13]C (calcite) reference curve based upon bulk samples from the Upper Cretaceous Chalk of England can be used as a primary criterion for trans-continental correlation is reviewed in the light of new stable isotope data from the Upper Albian and Cenomanian chalks of eastern England and from the Cenomanian to Campanian chalks of southern England. Evidence demonstrates that in the coloured chalks of eastern England the cements invariably have positive [delta^13]C values (up to 3.5[per mil]) except where they have been affected by hardground development when the cements have negative [delta^13]C values down to -6.5[per mil]. in contrast, the White Chalk of southern England may have cements with [delta^13]C values as negative as -8[per mil]. Modelling indicates that the coloured chalks may preserve a truer record of the primary palaeo-oceanographic [delta^13]C signal than the white and grey chalks of southern England. it is suggested that (1) many of the 72 isotope events described from the [delta^13]C (calcite) reference curve and proposed for correlation may reflect the effects of variations in the type and extent of calcite cementation; and (2) until much more is known about the patterns of calcite cementation in the Upper Cretaceous Chalk the use of minor isotope events for trans-continental stratigraphic correlation can only be applied with the utmost caution.
Źródło:: Acta Geologica Polonica; 2012, 62, 2; 173-196
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Note on the stable isotope values of vein calcite in the El-Seboah peralkaline granite (SW Egypt)
Autorzy:: Hassan, Kamaleldin M.
Powiązania:: https://bibliotekanauki.pl/articles/2086490.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: δ13C
δ18O
carbonate-hosting veins
peralkaline granite
Egypt
Opis:: Stable isotope data for carbon (δ13C) and oxygen (δ18O) are used to constrain the environments of calcite formation in two veins in the El-Seboah peralkaline granite in south-western Egypt. Vein I with calcitemagnetite-goethite-hematite-quartz, and vein II with calcite-magnetite-goethite-kaolinite-hematite-quartz are texturally distinct. The calcite of each vein has characteristic δ13C- and δ18O-values: + 0.32 and -7.28‰ for vein I and + 1.16 and - 1.21‰ for vein II, respectively. The observed differences between the δ13C values of the two veins indicate that they represent two separate systems of primary dissolved inorganic carbon formed at or near equilibrium with atmospheric CO2. The δ18O values, on the other hand, indicate calcite deposition from meteoric waters which were fresh for vein I and brackish for vein II.
Źródło:: Mineralogia; 2011, 42, 2/3; 113--120
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Estimation of soil water evaporative loss after tillage operation using the stable isotope technique
Autorzy:: Busari, M.A.
Salako, F.K.
Tuniz, C.
Zuppi, G.M.
Stenni, B.
Adetunji, M.T.
Arowolo, T.A.
Powiązania:: https://bibliotekanauki.pl/articles/25434.pdf
Data publikacji:: 2013
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:: Application of stable isotopes in soil studies has improved quantitative evaluation of evaporation and other hydrological processes in soil. This study was carried out to determine the effect of tillage on evaporative loss of water from the soil. Zero tillage and conventional tillage were compared. Suction tubes were installed for soil water collection at the depths 0.15, 0.50, and 1.0 m by pumping soil water with a peristaltic pump. Soil water evaporation was estimated using stable isotopes of water. The mean isotopic composition of the soil water at 0.15 m soil depth were -1.15‰ (d18O) and -0.75‰ (dD) and were highly enriched compared with the isotopic compositions of the site precipitation. Soil water stable isotopes (d18O and dD) were more enriched near the surface under zero tillage while they were less negative down the profile under zero tillage. This suggests an occurrence of more evaporation and infiltration under conventional then zero tillage, respectively, because evaporative fractionation contributes to escape of lighter isotopes from liquid into the vapour phase leading to enrichment in heavy isotopes in the liquid phase. The annual evaporation estimated using the vapour diffusion equation ranges from 46-70 and 54-84 mm year-1 under zero and conventional tillage, respectively, indicating more evaporation under conventional tillage compared with zero tillage. Therefore, to reduce soil water loss, adoption of conservation tillage practices such as zero tillage is encouraged.
Źródło:: International Agrophysics; 2013, 27, 3
0236-8722
Pojawia się w:: International Agrophysics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Comparison of two models in the estimation of nitrogen uptake rates using data from 15-N incubation experiments
Autorzy:: Tungaraza, C.
Brion, N.
Baeyens, W.
Powiązania:: https://bibliotekanauki.pl/articles/48263.pdf
Data publikacji:: 2005
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: marine environment
nitrogen isotope
Elskens' model
phytoplankton
nitrogenous nutrient
comparison
Opis:: This paper compares two uptake rate models, Dugdale & Goering’s (D&G) model and Elskens’ model. The aim is to provide an insight into how estimates of uptake processes, i.e. regeneration and loss rates from both dissolved and particulate nitrogen pools, influence the total uptake rates when the two models are compared. The uptake rates of three nitrogenous nutrients (nitrate, ammonium and urea) from 15-N incubation experimental data were compared. The comparison indicated that the D&G model underestimated nitrate uptake rates by about 34%, implying a significant regeneration and loss rates of the nutrient. Elskens’ model further showed that the loss rates from the dissolved phase were about 40% and 25% for the ammonium and urea pools, respectively, indicating that the D&G model underestimated the experimental uptake rates of the nutrients. On average, nitrification made up about 30% of the total ammonium uptake flux, whereas the sinks from particulate nitrogen and dissolved nitrogen were estimated at 36% and 56%, respectively. The D&G model sometimes overestimated the f-ratio values to about 60% and higher as a result of ammonium and urea uptake rates underestimation. This paper also shows that detritus adsorption, bacterial uptake and cell lysis are equally important processes.
Źródło:: Oceanologia; 2005, 47, 3
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan
Autorzy:: Pelc, Andrzej
Hałas, Stanisław
Niedźwiedzki, Robert
Powiązania:: https://bibliotekanauki.pl/articles/2086485.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: Bartonian
carbonate
Mangyshlak peninsula
phosphate
shark teeth
δ18O
δ13C
Opis:: We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.
Źródło:: Mineralogia; 2011, 42, 1; 53--61
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 16.

Tytuł:: Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan
Autorzy:: Pelc, A.
Hałas, S.
Niedźwiedzki, R.
Powiązania:: https://bibliotekanauki.pl/articles/2086536.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: Bartonian
carbonate
Mangyshlak peninsula
phosphate
shark teeth
δ18O
δ13C
Opis:: We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.
Źródło:: Mineralogia; 2011, 42, 1; 53--61
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 17.

Tytuł:: Zapis delta exp.13C w osadach pogranicza dewonu i karbonu w południowej części Gór Świętokrzyskich
Carbon isotope record in sediments of the Devonian-Carboniferous boundary in the southern Holy Cross Mountains
Autorzy:: Trela, W.
Malec, J.
Powiązania:: https://bibliotekanauki.pl/articles/2074535.pdf
Data publikacji:: 2007
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: izotopy węgla
wapienie
osady popgranicza Devonu i Karbonu
zdarzenie Hangenberg
Góry Świętokrzyskie
Carbon isotope signature
limestones
Devonian/Carboniferous boundary
Hangenberg Event
Holy Cross Mountains
Opis:: The delta exp.13C curve is presented for the Devonian-Carboniferous boundary (from the expansa to sandbergi conodont zones) outcropped at Kowala in the western Holy Cross Mountains, Poland. A positive carbon excursion is reported within micritic limestones corresponding to the upper (or even uppermost middle) praesulcata conodont zone, which coincides with the glacio-eustatic sea-level drop. The positive shift in the carbon isotope signature was preceded by a mass extinction of the ostracode, conodont and ammonite fauna coeval with the Hangenberg Event.
Źródło:: Przegląd Geologiczny; 2007, 55, 5; 411-415
0033-2151
Pojawia się w:: Przegląd Geologiczny
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 18.

Tytuł:: Use of sulphur and carbon stable-isotope composition of fish scales and muscles to identify the origin of fish
Autorzy:: Trembaczowski, Andrzej
Powiązania:: https://bibliotekanauki.pl/articles/2086488.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: stable isotopes
δ34S
δ13C
fish scales
fish muscle
food web relations
Opis:: δ34S and δ13C analyses were used to determine the origin of trout specimens. The isotope record of their scales and muscles are compared with a database previously obtained from wild- and reared fish coming from Polish rivers and pond farms. The comparison made it possible to find out whether the trout were wild or reared.
Źródło:: Mineralogia; 2011, 42, 1; 33--37
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 19.

Tytuł:: Use of sulphur and carbon stable-isotope composition of fish scales and muscles to identify the origin of fish
Autorzy:: Trembaczowski, A.
Powiązania:: https://bibliotekanauki.pl/articles/2086538.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: stable isotopes
δ34S
δ13C
fish scales
fish muscle
food web relations
Opis:: δ34S and δ13C analyses were used to determine the origin of trout specimens. The isotope record of their scales and muscles are compared with a database previously obtained from wild- and reared fish coming from Polish rivers and pond farms. The comparison made it possible to find out whether the trout were wild or reared.
Źródło:: Mineralogia; 2011, 42, 1; 33--37
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 20.

Tytuł:: 13C-urea breath test for detection of Helicobacter pylori and its correlation with endoscopic and histologic findings
Autorzy:: Hilker, E
Domschke, W.
Stoll, R.
Powiązania:: https://bibliotekanauki.pl/articles/71128.pdf
Data publikacji:: 1996
Wydawca:: Polskie Towarzystwo Fizjologiczne
Tematy:: gastritis
gastric ulcer
infection
mucosa
endoscopical finding
duodenal ulcer
urea breath test
Helicobacter pylori
gastric carcinoma
lymphatic tissue
ulcer
stable isotope
histological finding
stomach
urease
malignant lymphoma
Źródło:: Journal of Physiology and Pharmacology; 1996, 47, 1
0867-5910
Pojawia się w:: Journal of Physiology and Pharmacology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 21.

Tytuł:: Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, UK: Direct evidence from calcite-filled vugs in brachiopods
Autorzy:: Hu, X.
Jeans, C.
Dickson, T.
Powiązania:: https://bibliotekanauki.pl/articles/139259.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: cement kalcytowy
diageneza
historia
izotopy stabilne
kreda
pierwiastki śladowe
wpływ drobnoustrojów
anoxia
calcite cement
chalk
diagenesis
history
Microbial influence
oxia
stable isotopes
suboxia
trace elements
Opis:: The history of research into the cementation of the Upper Cretaceous Chalk of the UK is reviewed. Calcite-filled vugs within the shell cavities of terebratulid brachiopods from the Cenomanian Chalk of eastern england have been investigated by cathodoluminesence imaging, staining, electron microprobe and stable isotope analysis. This has provided the first detailed analysis of the geochemistry of the Chalk.s cement. two cement series, suboxic and anoxic, are recognized. Both start with a Mg-rich calcite with positive [delta^13]C values considered to have been precipitated under oxic conditions influenced by aerobic ammonification. The suboxic series is characterized by positive [delta^13]C values that became increasingly so as cementation progressed, reaching values of 3.5[per mil]. Manganese is the dominant trace element in the earlier cement, iron in the later cement. Mn-and Fe-reducing microbes influenced cement precipitation and the trace element and [delta^13]C patterns. The anoxic series is characterized by [delta^13]C values that became increasingly negative as cementation progressed, reaching values of .6.5[per mil]. Trace elements are dominated by iron and manganese. Sulphate-reducing microbes influenced cement precipitation and the trace element and [delta^13]C patterns. Both cement series are related closely to lithofacies and early lithification pre-dating the regional hardening of the Chalk. The suboxic series occurs in chalk which was continuously deposited and contained hematite pigment and limited organic matter. The anoxic series was associated with slow to nil deposition and hardground development inc halks that originally contained hematite pigment but no longer do so, and an enhanced supply of organic matter.
Źródło:: Acta Geologica Polonica; 2012, 62, 2; 143-172
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 22.

Tytuł:: Element enrichment and provenance of the detrital component in Holocene sediments from the Western Black Sea
Autorzy:: Dekov, V.M.
Darakchieva, V.Y.
Billstrom, K.
Garbe-Schonberg, C.D.
Kamenov, G.D.
Gallinari, M.
Dimitrov, L.
Ragueneau, O.
Kooijman, E.
Powiązania:: https://bibliotekanauki.pl/articles/2079273.pdf
Data publikacji:: 2020
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: trace element concentration
isotope analysis
enrichment factor
Holocene sediment
catchment area
geochemical analysis
Black Sea
Opis:: Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb.
Źródło:: Oceanologia; 2020, 62, 2; 139-163
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 23.

Tytuł:: The rank of climatic oscillations during MIS 11c (OHO and YHO) and post-interglacial cooling during MIS 11b and MIS 11a in eastern Poland
Autorzy:: Hrynowiecka, Anna
Żarski, Marcin
Drzewicki, Wojciech
Powiązania:: https://bibliotekanauki.pl/articles/2058672.pdf
Data publikacji:: 2019
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: substages of MIS 11
Mazovian interglacial
Holsteinian Interglacial
MIS 12 and MIS 10 glaciation range
palaeoclimate changes
E Poland palaeolakeland
Carbon isotope
Opis:: Lacustrine sediments representing Marine Isotope Stage 11 (MIS 11) were found in Hermanów (SE Poland) in a present-day closed depression under a thin cover of Weichselian and Holocene deposits (1.4 m). These sediments filled a palaeolake created as a result of melting of a dead-ice block at the end of MIS 12. Geological research has excluded the presence of an ice sheet during MIS 12 in this area. The lobe of the ice sheet of this glaciation was located several kilometres to the west of Hermanów. The palaeolake was part of a larger palaeolakeland in southeastern Poland, formed during MIS 11. The palaeomorphology of this interglacial is evident in the contemporary relief of the area and the outline of the lakes corresponds to the pattern of the closed palaeodepressions. Based on the record of sediments from Hermanów, a new perspective regarding the sub-division of MIS 11 is presented. Two regressive phases are observed in the Holsteinian Interglacial (MIS 11c) - OHO and YHO. The subsequent substages with five cold fluctuations according to the newest stratigraphic standards should be assigned to MIS 11b with a very clear cooling and a slightly warmer MIS 11a. Carbon isotopic composition of organic matter corroborates geological and environmental analysis. The isotopic composition suggests two cooling periods: OHO and MIS 11b. Stable climatic conditions with little temperature fluctuations persisted between the cooling periods.
Źródło:: Geological Quarterly; 2019, 63, 2; 375--394
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 24.

Tytuł:: Regional hardening of Upper Cretaceous Chalk in eastern England, UK: trace element and stable isotope patterns in the Upper Cenomanian and Turonian Chalk and their significance
Autorzy:: Jeans, C. V.
Long, D.
Hu, X.-F.
Mortimore, R. N.
Powiązania:: https://bibliotekanauki.pl/articles/139436.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: chalk hardening
trace elements
stable isotopes
cement modelling
reservoir diagenesis
history
kreda
hartowanie
pierwiastki śladowe
izotopy trwałe
cement
historia
Opis:: The regional hardening of the Late Cenomanian to Early Turonian Chalk of the Northern Province of eastern England has been investigated by examining the pattern of trace elements and stable carbon and oxygen isotopes in the bulk calcite of two extensive and stratigraphically adjacent units each 4 to 5 m thick of hard chalk in Lincolnshire and Yorkshire. These units are separated by a sequence, 0.3–1.3 m thick, of variegated marls and clayey marls. Modelling of the geochemistry of the hard chalk by comparison with the Standard Louth Chalk, combined with associated petrographic and geological evidence, indicates that (1) the hardening is due to the precipitation of a calcite cement, and (2) the regional and stratigraphical patterns of geochemical variation in the cement are largely independent of each other and have been maintained by the impermeable nature of the thin sequence of the clay-rich marls that separate them. Two phases of calcite cementation are recognised. The first phase was microbially influenced and did not lithify the chalk. It took place predominantly in oxic and suboxic conditions under considerable overpressure in which the Chalk pore fluids circulated within the units, driven by variations in compaction, temperature, pore fluid pressure and local tectonics. There is evidence in central and southern Lincolnshire of the loss of Sr and Mg-enriched pore fluids to the south during an early part of this phase. The second phase of calcite precipitation was associated with the loss of overpressure in probably Late Cretaceous and in Cenozoic times as the result of fault movement in the basement penetrating the overlying Chalk and damaging the seal between the two chalk units. This greatly enhanced grain pressures, resulting in grain welding and pressure dissolution, causing lithification with the development of stylolites, marl seams, and brittle fractures. Associated with this loss of overpressure was the penetration of the chalk units by allochthonous fluids, rich in sulphate and hydrocarbons, derived probably from the North Sea Basin. Microbial sulphate-reduction under anoxic conditions within these allochthonous fluids has been responsible for dissolving the fine-grained iron and manganese oxides within the chalk, locally enriching the Fe and Mn content of the calcite cement. The possibility is discussed that the pattern of cementation preserved in these regionally hard chalks of Late Cenomanian and Early Turonian age may be different from that preserved in the younger (late Turonian to Campanian) more basinal chalks of eastern England.
Źródło:: Acta Geologica Polonica; 2014, 64, 4; 419-455
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki