Leading Russian researchers of the Arctic are working these days in the expedition in the Eastern Arctic Seas. The expedition is based on the flagship of the Russian scientific fleet Academician M. Keldysh. Scientists carry out a complex of biogeochemical, geophysical and geological studies aimed at solving a number of priority tasks in accordance with the strategy for Scientific and Technological Development of the Russian Federation. First of all, this is the research of the state of underwater permafrost, the state of the environment along the Northern Sea Route (NSR), streams of greenhouse gases and other components of the carbon cycle in the Arctic land-shelf-atmosphere system. The expedition leader, RAS Associate Member, TPU Professor Igor Semiletov told about the first outcomes of the expedition.
- Prof Semiletov, could you specify the main priorities of the expedition, tell on how it is run, the main preliminary outcomes, and directions for further development.
- Underwater permafrost in the Eastern Arctic Seas (EAS) became warmer than the ground permafrost by 8-10 ° C, i.e. it has taken a temperature close to the phase of transition temperature and in many places, its significant or complete degradation has already occurred. This means that giant reservoirs of natural gas (mainly methane) in a free or hydrate forms have been already engaged in the modern biogeochemical cycle. Regarding the preliminary outcomes already obtained in the expedition, we can confidently say that the majority of the studied seeps significantly increased in size compared to the recent observations made in the expeditions of 2014 (the Russian-Sweden expedition onboard the Oden scientific icebreaker and ) and 2016 (the Russian expedition on the vessel Academician M. Lavrentiev).
For the first time, samples of bubbles were taken directly at the bottom in the amount sufficient to determine the isotopic signature of methane (with a small admixture of ethane). The same samples will be also used to analyze the isotopic composition of noble gases (including the He3 / He4 ratio) which will make it possible to clarify the genesis of bubble methane. Particular attention is paid to microbiological studies including the identification of methane formation and methane oxidation in sediments and water column (the group of the RAS Biotechnology Federal Research Center).
Previously, on the basis of a complete isotopic analysis (C13, deuterium, C14), we showed that the bubble transfer in the lithosphere – water column system to the EAS is determined by the contribution of all known sources: biogenic, thermogenic, and abiogenic. However, the ratio of the contribution of these sources varies in space and time, which may be due to the strengthening or absence of seismotectonic factors, for example, earthquakes and others, and accordingly due to the opening or closing of deep channels for the discharge of bubble methane.
To find out how deep the discharge channels are, the expedition conducts seismological studies by installing bottom seismological stations. They are set for 1-2 weeks or a year. Five ground stations of the IO RAS (Leopold Lobkovsky group) have already been installed for a period of one year, which for the first time, in conjunction with the stations installed earlier in the Lena River delta, will allow covering the entire shelf of the Laptev Sea. For the first time for a deep tomography of the bottom, 16 bottom stations were installed on one of the mega-seeps for a week, which immediately after installation were sounded with a powerful oscillating signal provided by the seismic group of the Center for Marine Research of Moscow State University.
Other areas of research of our expedition include the study of characteristic features of transport and transformation of terrestrial organic matter (OM) in the land-shelf system of the EAS and the environmental aspects of the state of the waters along the NSR.
Hydrochemical studies are carried out under the guidance of our compatriot Evgeniy Yakushev, principal researcher at the Norwegian Institute for Water Resources, who performs a number of joint researches with IO RAS and Moscow State University.
- Thank you for the detailed answer. Let us hope that the scientific consortium established to solve the most relevant challenges of the Russian Arctic Shelf will be included into the list of teams recognized for further support within the national project Nauka. The last question for today. Can you explain how the outcomes of your research team will address the applied issues arising in the exploration and development of the Russian Arctic Shelf?
- At present, there is no target program in the Russian Federation to study the distribution and state of underwater permafrost, despite the fact that there are numerous accidents arising from underreporting of scientifically based results from the study of the distribution and stability of underwater permafrost and the associated gas hydrates. The consequences of geoecological catastrophes that may occur during exploration and industrial activity carried out without taking into account the latest achievements of the research team (uncontrolled release of hydrated gas, etc.) may cause enormous material damage. We all remember the catastrophic consequences of the recent accident in the Gulf of Mexico, as well as in the Pechora Sea. The formation of Yamal funnels clearly demonstrates what can happen at any time in the vast areas of the EAS.
We also believe that the practical application of technologies developed by our team of authors to estimate the quantitative emission of bubbly methane from bottom sediments by means of absolute calibration of single-beam and multipath sonars, which can and should be used to search for gaps in underwater gas pipelines and assess economic and environmental damage caused by massive leaks has a huge potential.