Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and oxygen-18 in accreted ice

TY - JOUR

T1 - Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and oxygen-18 in accreted ice

AU - Ekaykin, A. A.

AU - Lipenkov, V. Y.

AU - Petit, J. R.

AU - Johnsen, Sigfus Johann

AU - Jouzel, J.

AU - Masson-Delmotte, V.

PY - 2010/5/4

Y1 - 2010/5/4

N2 - 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 noncovariantbehavior of deuterium and oxygen-18 isotopes in the lake ice.

AB - 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 noncovariantbehavior of deuterium and oxygen-18 isotopes in the lake ice.

U2 - 10.1029/2009jc005329

DO - 10.1029/2009jc005329

M3 - Journal article

SN - 0148-0227

VL - 115

SP - C05003

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

ER -