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Jean Jouzel - One of the best experts on this subject based on the ideXlab platform.
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insights into hydrological regime of lake vostok from differential behavior of deuterium and Oxygen 18 in accreted ice
Journal of Geophysical Research, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jeanrobert Petit, S. J. Johnsen, Jean Jouzel, Valerie MassondelmotteAbstract:[1] We use isotopic data (deuterium and Oxygen-18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen-18 isotopes in the lake ice.
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Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and Oxygen‐18 in accreted ice
Journal of Geophysical Research. Oceans, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jean Jouzel, J.r. Petit, S. Johnsen, Valérie Masson-delmotteAbstract:We use isotopic data (deuterium and Oxygen‐18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen‐18 isotopes in the lake ice.
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Atmospheric Oxygen 18 and sea-level changes
Quaternary Science Reviews, 2001Co-Authors: Jean Jouzel, Georg Hoffmann, Frédéric Parrenin, Claire WaelbroeckAbstract:Past isotopic composition of atmospheric Oxygen (δ18Oatm) can be inferred from the analysis of air bubbles trapped in ice caps. The longest record covers the last 420 ka (thousand of years) at the Vostok site in East Antarctica. It shows a strong modulation by the precession and striking similarities, but also noticeable differences, with the deep-sea core Oxygen 18 record from which changes in the Oxygen content of sea-water (δ18Osw) and in sea-level can be derived. Indeed, δ18Oatm is driven by complex fractionation processes occuring during respiration and photosynthesis. Both δ18Oatm and its difference with respect to δ18Osw (the Dole effect) are influenced by factors such as the ratio of oceanic and terrestrial productivities which may have significantly changed between different climates. Also, the response time of δ18Oatm to oceanic changes should be taken in consideration but this parameter itself depends on biospheric activity. We review the various aspects of the link between the δ18Oatm and the δ18Osw signals. We also examine the approach followed by Shackleton (Science (2000)) for deriving sea-level change from the δ18Oatm Vostok record, assuming that the phase between this record and insolation changes is constant and that the Dole effect is a fraction of the precessional component of the δ18Oatm signal. Glaciological constraints on the Vostok chronology and the complexity of the Dole effect show that those two assumptions are quite probably too simplistic.
Alexey A Ekaykin - One of the best experts on this subject based on the ideXlab platform.
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insights into hydrological regime of lake vostok from differential behavior of deuterium and Oxygen 18 in accreted ice
Journal of Geophysical Research, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jeanrobert Petit, S. J. Johnsen, Jean Jouzel, Valerie MassondelmotteAbstract:[1] We use isotopic data (deuterium and Oxygen-18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen-18 isotopes in the lake ice.
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Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and Oxygen‐18 in accreted ice
Journal of Geophysical Research. Oceans, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jean Jouzel, J.r. Petit, S. Johnsen, Valérie Masson-delmotteAbstract:We use isotopic data (deuterium and Oxygen‐18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen‐18 isotopes in the lake ice.
Valérie Masson-delmotte - One of the best experts on this subject based on the ideXlab platform.
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Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and Oxygen‐18 in accreted ice
Journal of Geophysical Research. Oceans, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jean Jouzel, J.r. Petit, S. Johnsen, Valérie Masson-delmotteAbstract:We use isotopic data (deuterium and Oxygen‐18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen‐18 isotopes in the lake ice.
Valerie Massondelmotte - One of the best experts on this subject based on the ideXlab platform.
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insights into hydrological regime of lake vostok from differential behavior of deuterium and Oxygen 18 in accreted ice
Journal of Geophysical Research, 2010Co-Authors: Alexey A Ekaykin, V Lipenkov, Jeanrobert Petit, S. J. Johnsen, Jean Jouzel, Valerie MassondelmotteAbstract:[1] We use isotopic data (deuterium and Oxygen-18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high Oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and Oxygen-18 isotopes in the lake ice.
Kris Gevaert - One of the best experts on this subject based on the ideXlab platform.
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Global differential non-gel proteomics by quantitative and stable labeling of tryptic peptides with Oxygen-18
Journal of proteome research, 2004Co-Authors: An Staes, Hans Demol, Jozef Van Damme, Lennart Martens, Joël Vandekerckhove, Kris GevaertAbstract:We describe a protocol for quantitative labeling of tryptic peptides with Oxygen-18. Proteins are first digested in natural water with trypsin, the pH is then lowered to 4.5 and the mixture is dried. Oxygen-18 water is added and two Oxygen-18 atoms are incorporated at the peptides' carboxyl termini. Trypsin is finally inactivated by cysteine alkylation under denaturing conditions, which blocks Oxygen back-exchange. The general value of this labeling strategy for differential proteomics is illustrated by the analysis and identification of several couples of differently labeled amino terminal peptides isolated from a human platelet proteome by a previously described chromatographic procedure. Keywords: nongel proteomics • mass spectrometry • Oxygen-18 • differential analysis • COFRADIC
