175 research outputs found
Evidence of change in UK atmospheric composition as a result of Icelandic volcanic emissions in 2014
Abstract relates to a poster presentation at the European Geosciences Union General Assembly 2015
Ультраструктура поверхні листків деяких сортів Syringa vulgaris L.
The results of comparative investigation of leaf surface ultrastructure of class Syringa vulgaris L. ‘Ogni Donbassa’ and ‘Krasavitsa Moskvy’ in the norm and under the silicone organic and mineral maturing action in monoculture garden of lilac’s of M.M. Gryshko National Botanical Gardens of the NAS of Ukraine are presented.Наведено результати порівняльного дослідження ультраструктури поверхні листків сортів Syringa vulgaris L. 'Вогні Донбасу' і 'Красавиця Москви' в нормі та під дією кремнієвмісного органо-мінерального добрива в монокультурному саду бузків НБС ім. М.М. Гришка НАН України
Tunable diode laser measurements of hydrothermal/volcanic CO2 and implications for the global CO2 budget
Quantifying the CO2 flux sustained by low-temperature fumarolic fields in hydrothermal/volcanic environments has remained a challenge, to date. Here, we explored the potential of a commercial infrared tunable laser unit for quantifying such fumarolic volcanic/hydrothermal CO2 fluxes. Our field tests were conducted between April 2013 and March 2014 at Nea Kameni (Santorini, Greece), Hekla and Krýsuvík (Iceland) and Vulcano (Aeolian Islands, Italy). At these sites, the tunable laser was used to measure the path-integrated CO2 mixing ratios along cross sections of the fumaroles' atmospheric plumes. By using a tomographic post-processing routine, we then obtained, for each manifestation, the contour maps of CO2 mixing ratios in the plumes and, from their integration, the CO2 fluxes. The calculated CO2 fluxes range from low (5.7 ± 0.9 t d−1; Krýsuvík) to moderate (524 ± 108 t d−1; La Fossa crater, Vulcano). Overall, we suggest that the cumulative CO2 contribution from weakly degassing volcanoes in the hydrothermal stage of activity may be significant at the global scale
Tunable diode laser measurements of hydrothermal/volcanic CO2 and implications for the global CO2 budget
Quantifying the CO2 flux sustained by lowtemperature fumarolic fields in hydrothermal/volcanic environments
has remained a challenge, to date. Here, we explored the potential of a commercial infrared tunable laser unit for quantifying such fumarolic volcanic/hydrothermal CO2 fluxes. Our field tests were conducted between April 2013 and March 2014 at Nea Kameni (Santorini, Greece), Hekla and Krýsuvík (Iceland) and Vulcano (Aeolian
Islands, Italy). At these sites, the tunable laser was used to measure the path-integrated CO2 mixing ratios along cross
sections of the fumaroles’ atmospheric plumes. By using a tomographic post-processing routine, we then obtained, for each manifestation, the contour maps of CO2 mixing ratios in the plumes and, from their integration, the CO2 fluxes. The
calculated CO2 fluxes range from low (5.7 +/- 0.9 t d-1; Krýsuvík) to moderate (524 +/-108 t d-1; La Fossa crater, Vulcano).
Overall, we suggest that the cumulative CO2 contribution from weakly degassing volcanoes in the hydrothermal stage of activity may be significant at the global scale
Degassing pathways through the shallow magmatic-hydrothermal system of Poás
We report results from a multidisciplinary campaign carried out at Poás crater-lake (Costa Rica) on
17-18 March 2009. Thermal imagery of fumaroles on the north side of the dome and the lake surface revealed mean apparent temperatures of 25-40°C (maximum of 80°C), and 30-35°C (maximum of 48°C), respectively. Mean radiative heat output of the lake, uncorrected for downwelling flux, was estimated as ~230 MW. The mean SO2 flux emitted by the crater measured by walking-traverses was 76 tonnes day-1, with approximately equal contributions from both the dome and the lake and fumarole plumes. Gas measurements by active open-path FTIR spectroscopy
indicated molar ratios of H2O/SO2 = 151 and CO2/SO2 = 1.56. HCl and HF were not detected in measured spectra but based on the detection limits of these species, we calculate SO2/HCl > 40, and
SO2/HF > 200. Particles were sampled from the plume by air filtration. The filters were analysed using ion chromatography, which revealed an abundance of K+ and SO42-, with smaller amounts of Ca2+, Mg2+ and Cl-. We discuss here the implications of the results for degassing pathways through the shallow magmatic-hydrothermal system
Effusive eruption modelling project: assessing UK impacts of trace species and sulphur deposition
Role of a two-component ResD-ResE system in regulating the expression of guanyl-specific ribonuclease genes in Bacilli
The role of the two-component ResD-ResE signal transduction system in regulating the expression of guanyl-specific ribonuclease genes in bacilli has been studied. Proteins with homologies to the ResD and ResE regulatory proteins of Bacillus subtilis have been found in all sequenced genomes of Bacillus. It has been shown using the B. subtilis strains defective in genes of these proteins that the ResD-ResE signal transduction system positively regulates the expression of ribonuclease genes of B. intermedius, B. pumilus, and B. thuringiensis in cells of B. subtilis. The data obtained in this work speak for the fact that regulatory system similar to the two-component ResD-ResE signal transduction system of B. subtilis also functions in other representatives of the Bacillus genus. © 2008 Allerton Press, Inc
Insights into volcanic hazards and plume chemistry from multi-parameter observations: the eruptions of Fimmvörðuháls and Eyjafjallajökull (2010) and Holuhraun (2014–2015)
The eruptions of Eyjafjallajökull volcano in 2010 (including its initial effusive phase at Fimmvörðuháls and its later explosive phase from the central volcano) and Bárðarbunga volcano in 2014–2015 (at Holuhraun) were widely reported. Here, we report on complementary, interdisciplinary observations made of the eruptive gases and lavas that shed light on the processes and atmospheric impacts of the eruptions, and afford an intercomparison of contrasting eruptive styles and hazards. We find that (i) consistent with other authors, there are substantial differences in the gas composition between the eruptions; namely that the deeper stored Eyjafjallajökull magmas led to greater enrichment in Cl relative to S; (ii) lava field SO2 degassing was measured to be 5–20% of the total emissions during Holuhraun, and the lava emissions were enriched in Cl at both fissure eruptions—particularly Fimmvörðuháls; and (iii) BrO is produced in Icelandic plumes in spite of the low UV levels
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