Impact of the initialisation on the predictability of the Southern Ocean sea ice at interannual to multi-decadal timescales     

Violette Zunz  Hugues Goosse  Svetlana Dubinkina 《Climate Dynamics》2015,44(7-8):2267-2286

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Galactic cosmic ray variation influence on baric system dynamics at middle latitudes     

Irina Artamonova  Svetlana Veretenenko 《Journal of Atmospheric and Solar》2011,73(2-3):366-370

Variations of atmospheric pressure in the North Atlantic region during Forbush decreases of galactic cosmic rays were investigated. A noticeable pressure growth with the maximum on the 3rd and 4th days after the Forbush decrease onsets was revealed over Scandinavia and the northern region of the European part of Russia. It was shown that the observed pressure growth was caused by the formation of blocking anticyclones in the region of the climatic Arctic front, as well as by the sharp slowing of the movement of North Atlantic cyclones. It was suggested that the particles that precipitate in the regions of the climatic Arctic and Polar fronts, with the minimum energies E～20–80 MeV and ～2–3 GeV, respectively, may influence the processes of cyclone and anticyclone formation and development at extratropical latitudes.  相似文献   

Basic formation mechanisms of Lake Doroninskoye soda water,East Siberia,Russia     

Svetlana V. Borzenko  Leonid V. Zamana  Larisa I. Usmanova 《中国地球化学学报》2018,37(4):546-558

The primary scientific goal of studying salt lakes is to better understand the formation of small continental-type hydrogeochemical systems. Many scientists have attributed the metamorphism of the chemical composition of salt lakes to the evaporative concentration of water. However, the formation of soda water is inconsistent with this hypothesis. Thus, analyzing intrabasinal biochemical processes and water—rocks interactions during the evaporative concentration of water allows us to understand the major mechanisms of the formation and evolution of water compositions. Therefore, the aim of this paper is to identify the key processes involved in the formation of the chemical composition of the water in Lake Doroninskoye. An analysis of the distribution of major components shows that Na⁺, HCO₃ ^?, CO₃ ^2?, and Cl^? are dominant in this water. High concentrations of these elements are the result of evaporative water concentration. Calcium, magnesium, and potassium are not accumulated because the water is saturated in minerals containing these elements. The main barrier to the growth of the sulfate content of water is sulfate reduction. This process also contributes to the additional reproduction of carbon dioxide, which reacts with the products of the hydrolysis of aluminosilicates OH^? to form HCO₃ ^? and CO₃ ^2?, thus further contributing to the natural processes of soda formation.  相似文献   

Defining the Potential of Nanoscale Re‐Os Isotope Systematics Using Atom Probe Microscopy          下载免费PDF全文

Luke Daly  Phil A. Bland  Svetlana Tessalina  David W. Saxey  Steven M. Reddy  Denis Fougerouse  William D.A. Rickard  Lucy V. Forman  Alexandre La Fontaine  Julie M. Cairney  Simon P. Ringer  Bruce F. Schaefer  Daniel Schwander 《Geostandards and Geoanalytical Research》2018,42(3):279-299

Atom probe microscopy (APM) is a relatively new in situ tool for measuring isotope fractions from nanoscale volumes (< 0.01 μm³). We calculate the theoretical detectable difference of an isotope ratio measurement result from APM using counting statistics of a hypothetical data set to be ± 4δ or 0.4% (2s). However, challenges associated with APM measurements (e.g., peak ranging, hydride formation and isobaric interferences), result in larger uncertainties if not properly accounted for. We evaluate these factors for Re‐Os isotope ratio measurements by comparing APM and negative thermal ionisation mass spectrometry (N‐TIMS) measurement results of pure Os, pure Re, and two synthetic Re‐Os‐bearing alloys from Schwander et al. (2015, Meteoritics and Planetary Science, 50, 893) [the original metal alloy (HSE) and alloys produced by heating HSE within silicate liquid (SYN)]. From this, we propose a current best practice for APM Re‐Os isotope ratio measurements. Using this refined approach, mean APM and N‐TIMS ¹⁸⁷Os/¹⁸⁹Os measurement results agree within 0.05% and 2s (pure Os), 0.6–2% and 2s (SYN) and 5–10% (HSE). The good agreement of N‐TIMS and APM ¹⁸⁷Os/¹⁸⁹Os measurements confirms that APM can extract robust isotope ratios. Therefore, this approach permits nanoscale isotope measurements of Os‐bearing alloys using the Re‐Os geochronometer that could not be measured by conventional measurement principles.  相似文献   

Invertebrates of the relict steppe ecosystems of Beringia,and the reconstruction of Pleistocene landscapes     

Daniil Berman  Arcady Alfimov  Svetlana Kuzmina 《Quaternary Science Reviews》2011,30(17-18):2200-2219

Studies of invertebrates from steppe patches in the tundra and taiga zones of Beringia provide additional evidence that these areas could be relict steppes. A number of insect species common to both modern relict steppes and fossil Beringian insect faunal assemblages have been found. These provide important information on the moisture and temperature preferences of some of the surviving members of Pleistocene steppe-tundra insect communities. The most significant species of West Beringian insects are weevils in the genus Stephanocleonus (Coleoptera, Curculionidae), indicators of thermophytic steppe, and the pill beetle Morychus viridis (Coleoptera, Byrrhidae), the indicator of hemicryophytic steppe. The East Beringian invertebrate population of relict steppe is substantially different. Fossil evidence suggests that biotic exchange between the two parts of Beringia was limited during the Pleistocene; populations of steppe insects did not move across the Bering Land Bridge (BLB), while tundra species had more flexibility. The tundra environment reconstructed for the Pleistocene BLB should have facilitated amphi-beringian distributions for most tundra invertebrate species, but apparently only a few species achieved this.  相似文献   

Geochemical and microbiological characteristics of sediments near the Malenky mud volcano (Lake Baikal, Russia), with evidence of Archaea intermediate between the marine anaerobic methanotrophs ANME-2 and ANME-3   总被引：1，自引：1，他引：0  

Tamara I. Zemskaya  Tatiayna V. Pogodaeva  Olga V. Shubenkova  Svetlana M. Сhernitsina  Olga P. Dagurova  Savelii P. Buryukhaev  Bair B. Namsaraev  Oleg M. Khlystov  Aleksandr V. Egorov  Aleksei A. Krylov  Gennadii V. Kalmychkov 《Geo-Marine Letters》2010,30(3-4):411-425

Detailed lithological, biogeochemical and molecular biological analyses of core sediments collected in 2002–2006 from the vicinity of the Malenky mud volcano, Lake Baikal, reveal considerable spatial variations in pore water chemical composition, with total concentrations of dissolved salts varying from 0.1 to 1.8‰. Values of methane δ¹³С in the sediments suggest a biogenic origin (δ¹³С_min. ?61.3‰, δ¹³С_max. ?72.9‰). Rates of sulphate reduction varied from 0.001 to 0.7 nmol cm^?3 day^?1, of autotrophic methanogenesis from 0.01 to 2.98 nmol CH₄ cm^?3 day^?1, and of anaerobic oxidation of methane from 0 to 12.3 nmol cm^?3 day^?1. These results indicate that methanogenic processes dominate in gas hydrate-bearing sediments of Lake Baikal. Based on clone libraries of 16S rRNA genes amplified with Bacteria- and Archaea-specific primers, investigation of microbial diversity in gas hydrate-bearing sediments revealed bacterial 16S rRNA clones classified as Deltaproteobacteria, Gammaproteobacteria, Chloroflexi and OP11. Archaeal clone sequences are related to the Crenarchaeota and Euryarchaeota. Baikal sequences of Archaea form a distinct cluster occupying an intermediate position between the marine groups ANME-2 and ANME-3 of anaerobic methanotrophs.  相似文献   

Radionuclides and mercury in the salt lakes of the Crimea     

Natalya Mirzoyeva  Larisa Gulina  Sergey Gulin  Olga Plotitsina  Alexandra Stetsuk  Svetlana Arkhipova  Nina Korkishko  Oleg Eremin 《中国海洋湖沼学报》2015,33(6):1413-1425

90 Sr concentrations,resulting from the Chernobyl NPP accident,were determined in the salt lakes of the Crimea(Lakes Kiyatskoe,Kirleutskoe,Kizil-Yar,Bakalskoe and Donuzlav),together with the redistribution between the components of the ecosystems.The content of mercury in the waters of the studied reservoirs was also established.Vertical distributions of natural radionuclide activities( 238 U,232 Th,226 Ra,210 Pb,40 K) and anthropogenic 137 Cs concentrations(as radiotracers) were determined in the bottom sediments of the Koyashskoe salt lake(located in the south-eastern Crimea) to evaluate the longterm dynamics and biogeochemical processes.Radiochemical and chemical analysis was undertaken and radiotracer and statistical methods were applied to the analytical data.The highest concentrations of 90 Sr in the water of Lake Kiyatskoe(350.5 and 98.0 Bq/m 3) and Lake Kirleutskoe(121.3 Bq/m 3) were due to the discharge of the Dnieper water from the North-Crimean Canal.The high content of mercury in Lake Kiyatskoe(363.2 ng/L) and in seawater near Lake Kizil-Yar(364 ng/L) exceeded the maximum permissible concentration(3.5 times the maximum).Natural radionuclides provide the main contribution to the total radioactivity(artificial and natural combined) in the bottom sediments of Lake Koyashskoe.The significant concentration of 210 Pb in the upper layer of bottom sediments of the lake indicates an active inflow of its parent radionuclide—gaseous 222 Rn from the lower layers of the bottom sediment.The average sedimentation rates in Lake Koyashskoe,determined using 210 Pb and 137 Cs data,were 0.117 and 0.109 cm per year,respectively.  相似文献   

On the Nature of the Impactor That Formed the Shackleton Crater on the Moon     

Svetlana G. Pugacheva  Ekaterina A. Feoktistova  Vladislav V. Shevchenko 《Earth, Moon, and Planets》2016,118(1):27-50

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A new key pole for the East European Craton at 1452 Ma: Palaeomagnetic and geochronological constraints from mafic rocks in the Lake Ladoga region (Russian Karelia)     

Natalia V. Lubnina  Satu Mertanen  Ulf Söderlund  Svetlana Bogdanova  Tatiana I. Vasilieva  Dmitry Frank-Kamenetsky 《Precambrian Research》2010

Palaeomagnetic and geochronological studies on mafic rocks in the Lake Ladoga region in South Russian Karelia provide a new, reliably dated Mesoproterozoic key paleopole for the East European Craton (Baltica). U–Pb dating on baddeleyite gives a crystallisation age of 1452 ± 12 Ma for one of the studied dolerite dykes. A mean palaeomagnetic pole for the Mesoproterozoic dolerite dykes, Valaam sill and Salmi basalts yields a paleopole at 15.2°N, 177.1°E, A₉₅ = 5.5°. Positive baked contact test for the dolerite dykes and positive reversal test for the Salmi basalts and for the dykes confirm the primary nature of the magnetisation. Comparison of this Baltica palaeopole with coeval paleomagnetic data for Laurentia and Siberia provides a revised palaeoposition of these cratons. The results verify that the East European Craton, Laurentia and Siberia were part of the supercontinent Columbia from the Late Palaeoproterozoic to the Middle Neoproterozoic.  相似文献   

Nature of Co-bearing ferromanganese crusts of the Magellan Seamounts (Pacific Ocean): Communication 2. Ion exchange properties of ore minerals     

G. V. Novikov  S. V. Yashina  M. E. Mel’nikov  I. V. Vikent’ev  O. Yu. Bogdanova 《Lithology and Mineral Resources》2014,49(2):138-164

The results of experimental studies of ion exchange properties of Co-bearing ferromanganese crusts in the Magellan Seamounts (Pacific Ocean) are discussed. Maximum reactivity in reactions with the participation of manganese minerals (Fe-vernadite, vernadite) is typical of Na⁺, K⁺, and Ca²⁺ cations, whereas minimum activity is recorded for cations Pb²⁺ and Co²⁺. The exchange complex of ore minerals in crusts is composed of Na⁺, K⁺, Ca²⁺, Mg²⁺, and Mn²⁺ cations. The exchange capacity of manganese minerals increases from the alkali metal cations to rare and heavy metal cations. Peculiarities of the affiliation of Co²⁺, Mn²⁺, and Mg²⁺ cations in manganese minerals of crusts are discussed. In manganese minerals, Co occurs as Co²⁺ and Co³⁺ cations. Metal cations in manganese minerals occur in different chemical forms: sorbed (Na⁺, K⁺, Ca²⁺, Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺); sorbed and chemically bound (Mg²⁺, Ni²⁺, Y³⁺, La³⁺, and Mo⁶⁺); and only chemically bound (Co³⁺). It is shown that the age of crust, its preservation time in the air-dry state, and type of host substrate do not affect the ion exchange indicators of manganese minerals. It has been established that alkali metal cations are characterized by completely reversible equivalent sorption, whereas heavy metal cations are sorbed by a complex mechanism: equivalent ion exchange for all metal cations; superequivalent, partly reversible sorption for Ba²⁺, Pb²⁺, Co²⁺, and Cu²⁺ cations, relative to exchange cations of manganese minerals. The obtained results refine the role of ion exchange processes during the hydrogenic formation of Co-bearing ferromanganese crusts.  相似文献