scholarly journals Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

2016 ◽  
Vol 13 (1) ◽  
pp. 323-340 ◽  
Author(s):  
S. Walter ◽  
A. Kock ◽  
T. Steinhoff ◽  
B. Fiedler ◽  
P. Fietzek ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Molecular Hydrogen ◽  
Transport Model ◽  
Isotopic Signature ◽  
Water Masses ◽  
Atmospheric Measurements ◽  
Biological Production ◽  
Northern Atlantic ◽  
Main Components ◽  
First Time

Abstract. Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during 5 cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauritania.The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (−629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (−249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with the biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production, a significant different source should be considered.The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.

scholarly journals Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

2015 ◽  
Vol 12 (19) ◽  
pp. 16431-16477
Author(s):  
S. Walter ◽  
A. Kock ◽  
T. Steinhoff ◽  
B. Fiedler ◽  
P. Fietzek ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Molecular Hydrogen ◽  
Transport Model ◽  
Isotopic Signature ◽  
Water Masses ◽  
Atmospheric Measurements ◽  
Biological Production ◽  
Northern Atlantic ◽  
Main Components ◽  
First Time

Abstract. Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during five cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauretania. The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (−629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (−249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production a significant different source should be considered. The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.

Isolation and HPLC Determination of the Chemical Components of Gentianella acuta (Michx.) Hulten

2018 ◽  
Vol 15 (1) ◽  
pp. 21-33
Author(s):  
Ying Wei ◽  
Yongqiao Liu ◽  
Yifan Hele ◽  
Weiwei Sun ◽  
Yang Wang ◽  
...  
Keyword(s):  
Medicinal Plant ◽  
High Speed ◽  
Chemical Constituents ◽  
Folk Medicine ◽  
Gradient Elution ◽  
Chemical Components ◽  
Isolation And Characterization ◽  
Major Chemical ◽  
Main Components ◽  
First Time

Background: Gentianella acuta (Michx.) Hulten is an important type of medicinal plant found in several Chinese provinces. It has been widely used in folk medicine to treat various illnesses. However, there is not enough detailed information about the chemical constituents of this plant or methods for their content determination. Objective: The focus of this work is the isolation and characterization of the major chemical constituents of Gentianella acuta, and developing an analytical method for their determination. Methods: The components of Gentianella acuta were isolated using (1) ethanol extraction and adsorption on macroporous resin. (2) and ethyl acetate extraction and high speed countercurrent chromatography. A HPLC-DAD method was developed using a C18 column and water-acetonitrile as the mobile phase. Based on compound polarities, both isocratic and gradient elution methods were developed. Results: A total of 29 compounds were isolated from this plant, of which 17 compounds were isolated from this genus for the first time. The main components in this plant were found to be xanthones. The HPLC-DAD method was developed and validated for their determination, and found to show good sensitivity and reliability. Conclusion: The results of this work add to the limited body of work available on this important medicinal plant. The findings will be useful for further investigation and development of Gentianella acuta for its valuable medicinal properties.

Assessment of recreational use of specially protected natural territories of Tatishchevsky district of Saratov region

2019 ◽  
Vol 27 (2) ◽  
pp. 117-127
Author(s):  
Yulia M Andriyanova ◽  
Irina V Sergeeva ◽  
Yulia M Mokhonko ◽  
Natalia N Gusakova
Keyword(s):  
Natural Resources ◽  
Protected Areas ◽  
Saratov Region ◽  
Future State ◽  
Forest Phytocenoses ◽  
Long Time ◽  
Main Components ◽  
First Time ◽  
Recreational Use ◽  
Specially Protected Natural Territories

The influence of recreation being a set of measures to restore health and recreation, on the main components of forest phytocenoses in specially protected natural territories of the Tatishchevsky district of the Saratov region has been studied for the first time. These phytocenoses have been intensively used for tourism for a long time. The intensity and visits activity of protected areas has been determined; the recreational capacity of territorial objects has been studied. The degree of forest landscapes has been revealed in specially protected natural territories. The findings allow predicting the future state of the natural resources of the Saratov region and can be taken into account when assessing their optimal use.

scholarly journals Line observations of the 30-Dor complex and N159A5 with the MPE imaging NIR spectrometer FAST

1991 ◽  
Vol 148 ◽  
pp. 205-206 ◽  
Author(s):  
A. Krabbe ◽  
J. Storey ◽  
V. Rotaciuc ◽  
S. Drapatz ◽  
R. Genzel
Keyword(s):  
Spatial Resolution ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Emission Lines ◽  
Resolving Power ◽  
Max Planck ◽  
First Time ◽  
Infrared Array

Images with subarcsec spatial resolution in the light of near-infrared atomic (Bry) and molecular hydrogen H2 (S(1) v=1-0) emission lines were obtained for some extended, pointlike objects in the Large Magellanic Cloud (LMC) for the first time. We used the Max-Planck-Institut für extraterrestrische Physik (MPE) near-infrared array spectrometer FAST (image scale 0.8”/pix, spectral resolving power 950) at the ESO/MPI 2.2m telescope, La Silla. We present some results on the 30-Dor complex and N159A5.

scholarly journals AGN Spectra as Seen by the Infrared Space Observatory: First Results

1997 ◽  
Vol 159 ◽  
pp. 333-336
Author(s):  
D. Lutz ◽  
R. Genzel ◽  
E. Sturm ◽  
A.F.M. Moorwood ◽  
E. Oliva ◽  
...  
Keyword(s):  
Fine Structure ◽  
Short Wavelength ◽  
Molecular Hydrogen ◽  
Molecular Gas ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
First Results ◽  
External Galaxies ◽  
First Time ◽  
Fine Structure Lines

AbstractWe discuss 2.5–45 µm spectra of the Circinus galaxy and of Cen A, obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory. The large number of detected ionic fine structure lines, observable also in visually obscured sources, provides strong constraints on the shape of the ionizing spectrum, which is found to exhibit a UV bump peaking at ~ 70 eV in the case of Circinus. Pure rotational emission of molecular hydrogen, directly probing warm molecular gas, can for the first time be detected in external galaxies.

scholarly journals Presence of continental and Bay of Bengal moisture in rainfall at Kolkata, revealed through simultaneous observation from land and sea during South-West monsoon of 2004

2016 ◽  
Author(s):  
Shaakir Shabir Dar ◽  
Prosenjit Ghosh
Keyword(s):  
Isotopic Composition ◽  
Bay Of Bengal ◽  
Indian Subcontinent ◽  
Isotopic Signature ◽  
Peninsular India ◽  
Gangetic Plain ◽  
Prevailing Wind Direction ◽  
South West Monsoon ◽  
Continental Source ◽  
Sw Monsoon

Abstract. The backward air mass trajectory analysis (HYSPLIT) during the summer monsoon suggests that the rain which precipitates at Kolkata is generated from a moisture parcel which originates from the Arabian Sea and moves inland over the dry Indian subcontinent or over the Bay of Bengal. We used monthly satellite and ground based measurements of the hydro-meteorological variables together with isotope data from Bangalore, Bay of Bengal and Kolkata and other locations to quantify the contribution of different moisture sources during the SW Monsoon. The vapor mass as it moves under the prevailing wind direction was subjected to isotopic modification due to addition of evaporated moisture from Bay of Bengal and rainout process. This was simulated using Craig and Gordon model and Rayleigh fractionation model respectively. The moisture generated during the process of evaporation from Bay of Bengal surface ocean gets advected towards the continent and precipitates as rainfall or snowfall over the Indo-Gangetic plain. We assumed based on our observation that the initial isotopic composition of vapor originating from the peninsular continental source is similar to our observation recorded at Bangalore station. It is found that the isotopic signature of Bangalore is completely lost albeit the significant contribution of the moisture from Bay of Bengal. To explain the isotopic composition of precipitation at Kolkata during the SW-Monsoon, it was necessary to invoke 75–80 % moisture contribution from the Bay of Bengal whereas the evaporated moisture parcel from the Peninsular India contribute 25 %–35 %.

Synthesis, Crystal Structure, Luminescence and Electronic Band Structure of K2BiZr(PO4)3 Phosphate Compound

2015 ◽  
Vol 230 ◽  
pp. 55-61 ◽  
Author(s):  
Vitalii Chornii ◽  
Yuriy Hizhnyi ◽  
Sergiy G. Nedilko ◽  
Kateryna Terebilenko ◽  
I. Zatovsky ◽  
...  
Keyword(s):  
Electronic Band Structure ◽  
Spontaneous Crystallization ◽  
Electronic Band ◽  
Coordination Numbers ◽  
Crystallization Method ◽  
Oxygen Coordination ◽  
Spectroscopy Studies ◽  
Main Components ◽  
Flapw Method ◽  
First Time

The single crystals of langbeinite-related K2BiZr(PO4)3 have been obtained for the first time by spontaneous crystallization method from K-Zr-P-O-F molten system. The compound crystallizes in a space group P213 with cell parameter a = 10.30360 Å. The framework is built up from isolated Bi/ZrO6 octahedra connected together by PO4 units. For the two K+ cations two types of oxygen coordination numbers 9 and 12 are observed. The photoluminescence (PL) spectroscopy studies of K2BiZr(PO4)3 are carried out under the VUV synchrotron excitations. The electronic structure of K2BiZr(PO4)3 crystal is calculated by the FLAPW method. The PL spectra reveal two main components in the UV and visible spectral regions (peaking near 3.6 and 2.7 eV respectively). It is assumed that the <st1:address><st1:street>UV PL</st1:street></st1:address> component of K2BiZr(PO4)3 originates from transitions in ZrO6 polyhedra, while the visible one is related to Bi3+ ions in oxygen coordination.

Comparative analysis of the effect of epibrassinolide and 6-benzylaminopurine on the key components of the glutathione complex in the roots of wheat seedling under salinity.

Biomics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 20-26
Author(s):  
D.R. Maslennikova ◽  
F.M. Shakirova
Keyword(s):  
Comparative Analysis ◽  
Wheat Seedling ◽  
Glutathione System ◽  
Glutathione S Transferase ◽  
Wheat Seedlings ◽  
Comparable Level ◽  
Endogenous Cytokinins ◽  
Main Components ◽  
First Time

The study carried out a comparative analysis of the effect of 24 epibrassinolide (EB) and 6-benzylaminopurine (BAP) on the growth and state of the main components of the glutathione system in the roots of wheat seedlings under the action of 2% NaCl, which for the first time revealed the ability of these phytohormones to similarly stabilize stress-induced decrease GSH / GSSG ratio, positively regulate the activity of glutathione reductase and glutathione-S-transferase. A comparable level of protective effect of BAP and EB on root length was revealed. The data obtained indicate that endogenous cytokinins may play the role of hormonal intermediates in the implementation of the protective.

ISOTOPE-GEOCHEMICAL FEATURES OF AUTHENIC CARBONATES OF THE YU1 PRODUCING HORIZON OF THE VERKH-TARSKOYE OIL FIELD (SOUTH OF WESTERN SIBERIA)

2020 ◽  
pp. 20-28
Author(s):  
L. G. Vakulenko ◽  
◽  
O. D. Nikolenko ◽  
D. A. Novikov ◽  
P. A. Yan ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbonate Rocks ◽  
Western Siberia ◽  
Oil Field ◽  
Third Generation ◽  
The Third ◽  
First Time ◽  
Different Sources ◽  
Sources Of Co2 ◽  
Comprehensive Study

A comprehensive study of the composition of sand and silt deposits of the Yu1 horizon of the Vasyuganskaya Formation upper part of the Verkh-Tarskoye oil field has been carried out. Associations of authigenic minerals have been determined in their cement, among which the calcite is the most widespread. According to petrographic parameters, three generations of calcite have been identified for which detailed isotopicgeochemical and ultramicroscopic studies were carried out for the first time. Wide and multi directional changes in the isotopic composition of carbon and oxygen and in the chemical composition of carbonate minerals were recorded, they indicate significant variations in the conditions of diagenesis and catagenesis, primarily temperature, and different sources of CO2. Significant variations in the isotopic composition of formation waters and its relationship with the isotopic composition of carbonates have been established. Thus, a narrow interval of close δ13C values was revealed, amounting to –10.5 to –9.1 ‰ in the formation waters of group II, and from –10.7 to –9.1 ‰ in calcites of the third generation. The source of CO2 in this system should be considered a carbon dioxide, which is formed in the process of metamorphism of carbonate rocks of the Paleozoic age.

scholarly journals Measuring and modelling the isotopic composition of soil respiration: insights from a grassland tracer experiment

2011 ◽  
Vol 8 (5) ◽  
pp. 1333-1350 ◽  
Author(s):  
U. Gamnitzer ◽  
A. B. Moyes ◽  
D. R. Bowling ◽  
H. Schnyder
Keyword(s):  
Steady State ◽  
Isotopic Composition ◽  
Transport Model ◽  
Tracer Experiment ◽  
Atmospheric Co2 ◽  
Soil Co2 ◽  
Soil Air ◽  
Co2 Transport ◽  
Atmosphere System

Abstract. The carbon isotopic composition (δ13C) of CO2 efflux (δ13Cefflux) from soil is generally interpreted to represent the actual isotopic composition of the respiratory source (δ13CRs). However, soils contain a large CO2 pool in air-filled pores. This pool receives CO2 from belowground respiration and exchanges CO2 with the atmosphere (via diffusion and advection) and the soil liquid phase (via dissolution). Natural or artificial modification of δ13C of atmospheric CO2 (δ13Catm) or δ13CRs causes isotopic disequilibria in the soil-atmosphere system. Such disequilibria generate divergence of δ13Cefflux from δ13CRs (termed "disequilibrium effect"). Here, we use a soil CO2 transport model and data from a 13CO2/12CO2 tracer experiment to quantify the disequilibrium between δ13Cefflux and δ13CRs in ecosystem respiration. The model accounted for diffusion of CO2 in soil air, advection of soil air, dissolution of CO2 in soil water, and belowground and aboveground respiration of both 12CO2 and 13CO2 isotopologues. The tracer data were obtained in a grassland ecosystem exposed to a δ13Catm of −46.9 ‰ during daytime for 2 weeks. Nighttime δ13Cefflux from the ecosystem was estimated with three independent methods: a laboratory-based cuvette system, in-situ steady-state open chambers, and in-situ closed chambers. Earlier work has shown that the δ13Cefflux measurements of the laboratory-based and steady-state systems were consistent, and likely reflected δ13CRs. Conversely, the δ13Cefflux measured using the closed chamber technique differed from these by −11.2 ‰. Most of this disequilibrium effect (9.5 ‰) was predicted by the CO2 transport model. Isotopic disequilibria in the soil-chamber system were introduced by changing δ13Catm in the chamber headspace at the onset of the measurements. When dissolution was excluded, the simulated disequilibrium effect was only 3.6 ‰. Dissolution delayed the isotopic equilibration between soil CO2 and the atmosphere, as the storage capacity for labelled CO2 in water-filled soil pores was 18 times that of soil air. These mechanisms are potentially relevant for many studies of δ13CRs in soils and ecosystems, including FACE experiments and chamber studies in natural conditions. Isotopic disequilibria in the soil-atmosphere system may result from temporal variation in δ13CRs or diurnal changes in the mole fraction and δ13C of atmospheric CO2. Dissolution effects are most important under alkaline conditions.

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