Geological and hydrophysical studies from ice of Melky, hydrate-bearing seep

On February 25-28, 2025, field works were carried out from the ice in the middle basin of Lake Baikal, near Sukhaya village, within the State Assignments “Study of hydrate, oil and gaseous hydrocarbon systems functioning and associated microbial communities in Lake Baikal” (0279-2021-0006) (led by T.I. Zemskaya, O.M. Khlystov) and “Investigation of the advective and turbulent water exchange of Lake Baikal and its impact on the lake ecosystem, risks of catastrophic events” (0279-2021-0004) (led by I.A. Aslamov).

Field work was the final stage of monitoring the shallowest accumulations of gas hydrates at the bottom of Lake Baikal, located at depths of 372-378 m. High-precision pressure and temperature sensors were used to specify the depths in the seep Melky area and to study the temperature field of near-surface sediments of the bottom layer of water. We used the autonomous RBR temperature sensors, attached to the halyard along the entire depth of the water column, and THP, attached to the Pika cable-tool drill specially made for these works. This tool was penetrated over 2 m into bottom sediments, punching or stopping at gas hydrate layers. This work was necessary for the correct calculations and assessment of the role of the hydrate system in the transformation of the Lake Baikal bottom associated with the decomposition/formation of gas hydrates at the upper limit of their stability under current lake level fluctuations.