Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

/ M. L. Bagard [et al.] // Geochim. Cosmochim. Acta. - 2013. - Vol. 114. - P169-187, DOI 10.1016/j.gca.2013.03.038. - Cited References: 104. - We thank T. Bullen and two anonymous reviewers for their thorough and constructive reviews and A. Jacobson for editorial handling. S. Gangloff is thanked for her assistance with Ca isotope chemistry and T. Perrone for his help in measuring Sr isotopes. This work was supported by the French INSU-CNRS program "EC2CO-Cytrix", and CNRS program "GDRI CAR-WET-SIB, ANR "Arctic Metals", programs of presidium UroRAS and RAS. It was also supported by the funding from the Region Alsace, France, and the CPER 2003-2013 "REALISE". MLB benefited the funding of a Ph.D. scholarship from the French Ministry of National Education and Research. This is an EOST-LHyGeS contribution. . - 19. - ISSN 0016-7037РУБ Geochemistry & Geophysics

Аннотация: Stable Ca and radiogenic Sr isotope compositions were measured in different compartments (stream water, soil solutions, rocks, soils and soil leachates and vegetation) of a small permafrost-dominated watershed in the Central Siberian Plateau. The Sr and Ca in the area are supplied by basalt weathering and atmospheric depositions, which significantly impact the Sr isotopic compositions. Only vegetation significantly fractionates the calcium isotopes within the watershed. These fractionations occur during Ca uptake by roots and along the transpiration stream within the larch trees and are hypothesised to be the result of chromatographic processes and Ca oxalate crystallisations during Ca circulation or storage within plant organs. Biomass degradation significantly influences the Ca isotopic compositions of soil solutions and soil leachates via the release of light Ca, and organic and organo-mineral colloids are thought to affect the Ca isotopic compositions of soil solutions by preferential scavenging of Ca-40. The imprint of organic matter degradation on the delta Ca-44/40 of soil solutions is much more significant for the warmer south-facing slope of the watershed than for the shallow and cold soil active layer of the north-facing slope. As a result, the available stock of biomass and the decomposition rates appear to be critical parameters that regulate the impact of vegetation on the soil-water system in permafrost areas. Finally, the obtained delta Ca-44/40 patterns contrast with those described for permafrost-free environments with a much lower delta Ca-44/40 fractionation factor between soils and plants, suggesting specific features of organic matter decomposition in permafrost environments. The biologically induced Ca isotopic fractionation observed at the soil profile scale is not pronounced at the scale of the streams and large rivers in which the delta Ca-44/40 signature may be controlled by the heterogeneity of lithological sources. (C) 2013 Elsevier Ltd. All rights reserved.

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Держатели документа:
[Bagard, Marie-Laure
Schmitt, Anne-Desiree
Chabaux, Francois
Stille, Peter] Univ Strasbourg, F-67084 Strasbourg, France
[Bagard, Marie-Laure
Schmitt, Anne-Desiree
Chabaux, Francois
Stille, Peter] CNRS, EOST, LHyGeS, F-67084 Strasbourg, France
[Schmitt, Anne-Desiree] Univ Franche Comte, CNRS, UMR 6249, F-25030 Besancon, France
[Pokrovsky, Oleg S.
Viers, Jerome] Univ Toulouse 3, CNRS, UMR 5563, Geosci & Environm Toulouse, F-31400 Toulouse, France
[Pokrovsky, Oleg S.] Russian Acad Sci, Inst Ecol Problems North, Arkhangelsk, Russia
[Labolle, Francois] Univ Strasbourg, Inst Zool & Biol Gen, F-67000 Strasbourg, France
[Prokushkin, Anatoly S.] VN Sukachev Inst Forest SB RAS, Krasnoyarsk, Russia
Институт леса им. В.Н. Сукачева Сибирского отделения Российской академии наук : 660036, Красноярск, Академгородок 50/28

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Bagard, M.L.; Schmitt, A.D.; Chabaux, F...; Pokrovsky, O.S.; Viers, J...; Stille, P...; Labolle, F...; Prokushkin, A.S.