Methodological Approaches to Comparative Assessing the Activity and Intensity of Stream Bubble Gas Emissions on the Shelf off the Crimea Coast (Black Sea)

M. M. Makarov1, K. M. Kucher1, ✉, A. A. Budnikov2, T. V. Pomogaeva3, T. V. Malakhova3, 4, ✉

1 Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russian Federation

2 Lomonosov Moscow State University, Moscow, Russian Federation

3 A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Sevastopol, Russian Federation

4 International Scientific Center for Ecology and Climate Change, Sirius University of Science and Technology, Sirius, Russian Federation

✉ e-mail: t.malakhova@ibss-ras.ru

Abstract

Purpose. The purpose of the study is to detect bubble gas emissions and to quantitatively assess bubble gas fluxes on the Black Sea shelf off the southeastern coast of Crimea, as well as to focus specifically on methodological approaches to investigating the spatial localization and comparative evaluation of the activity and intensity of seafloor bubble gas emissions.

Methods and Results. The hydroacoustic records, seafloor video records, and hydrological measurement data collected during the scientific expeditions of R/V Professor Vodyanitsky (125th cruise, November 2022, 132nd cruise, July–August 2024, and 135th cruise, June 2025) were used in the study. The research consisted of three stages: 1) broad-scale shelf surveying at depths of 10–80 m, 2) boundary detailing of the sites with the identified seep clusters, and 3) monitoring of the activity of gas emissions at the selected sites. In total, more than 600 seeps were revealed over all the survey periods. Analysis of their distribution over depth showed that approximately 90% of all the recorded gas flares were located at depths of 35–45 m. To compare the temporal and spatial variability of gas emission activity, a specific indicator – the seep density (ratio of the seep number to the scanned bottom area) – was introduced. The maximum seep density reaching 6.3 seeps per hectare at the site near Cape Martyan was recorded in summer 2024. The hydroacoustic data made it possible to calculate the average values of gas emissions from individual seeps: 38 L/day (0.07 t/year) in 2022 and 10.7 L/day (0.011 t/year) in 2024.

Conclusions. The study results, including the data on spatial distribution, density dynamics, and flux magnitude, constitute the basis for monitoring gas emissions on the Crimean shelf. The pronounced interseasonal and interannual variability of seep density indicates the significant role of external factors in regulating gas emissions. The obtained data form a basis permitting assessment of the contribution of methane seeps to the regional carbon cycle.

Keywords

Black Sea, shelf, acoustic surveys, gas flares, seep, methane seep, bubble gas emission, hydroacoustic monitoring, South Coast of Crimea

Acknowledgements

The authors are grateful to the crew of R/V Professor Vodyanitsky for assistance with deck operations and navigation during the cruises. The study was carried out within the framework of state-funded research programs of Lomonosov MSU – No. 122052000076-3, LIN SB of RAS – No. 1023032700323-4-1.5.12 and No. 122012600083-9, FSBSI FRC IBSS – No. 124030100127-7, and the RSF grant No. 24-17-20030.

About the authors

Mikhail M. Makarov, Senior Researcher, Limnological Institute, Siberian Branch of the Russian Academy of Sciences (3 Ulan-Batorskaya Str., Irkutsk, 664033, Russian Federation), CSc. (Geogr.), ResearcherID: J-4851-2018, Scopus Author ID: 36845115900; ORCID ID: 0000-0002-1758-4458, SPIN-code: 6223-8328, mmmsoft@hlserver.lin.irk.ru

Konstantin M. Kucher, Leading Engineer, Limnological Institute, Siberian Branch of the Russian Academy of Sciences (3 Ulan-Batorskaya Str., Irkutsk, 664033, Russian Federation), kost@hlserver.lin.irk.ru

Andrey A. Budnikov, Senior Researcher, Lomonosov Moscow State University (1 Leninskie Gory, Moscow, 119991, Russian Federation), CSc. (Phys.-Math.), ORCID ID: 0000-0003-3452-2360, Scopus Author ID: 6602252189, WoS ResearcherID: E-9926-2014, SPIN-code: 1633-6870, budnikovaa@my.msu.ru

Tatiana V. Pomogaeva, Junior Researcher, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Ave., Sevastopol, 299011, Russian Federation), CSc. (Agric.), SPIN-code: 5721-4823, pomogtatyana@mail.ru

Tatiana V. Malakhova, Senior Researcher, Department of Radiation and Chemical Biology, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Ave., Sevastopol, 299011, Russian Federation); International Scientific Center for Ecology and Climate Change, Sirius University of Science and Technology (1 Olympiysky Ave., Sirius Federal Territory, Russian Federation), CSc. (Biol.), ORCID ID: 0000-0002-9653-7341, ResearcherID: ABE-3955-2020, Scopus Author ID: 56585887900, SPIN-code: 4625-9702, t.malakhova@ibss-ras.ru

Original russian text

Original Russian Text © The Authors, 2026, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 42, Iss. 1, pp. 21–36 (2026)

For citation

Makarov, M.M., Kucher, K.M., Budnikov, A.A., Pomogaeva, T.V. and Malakhova, T.V., 2026. Methodological Approaches to Comparative Assessing the Activity and Intensity of Stream Bubble Gas Emissions on the Shelf off the Crimea Coast (Black Sea). Physical Oceanography, 33(1), pp. 18-32.

References

  1. Etiope, G., Feyzullayev, A. and Baciu, C.L., 2009. Terrestrial Methane Seeps and Mud Volcanoes: A Global Perspective of Gas Origin. Marine and Petroleum Geology, 26(3), pp. 333-344. https://doi.org/10.1016/j.marpetgeo.2008.03.001
  2. Judd, A.G., 2004. Natural Seabed Gas Seeps as Sources of Atmospheric Methane. Environmental Geology, 46(8), pp. 988-996. https://doi.org/10.1007/s00254-004-1083-3
  3. Kvenvolden, K.A., Lorenson, T.D. and Reeburgh, W.S., 2001. Attention Turns to Naturally Occurring Methane Seepage. EOS, Transactions American Geophysical Union, 82(40), pp. 457. https://doi.org/10.1029/01EO00275
  4. Egorov, V.N., Artemov, Yu.G. and Gulin, S.B., 2011. [Methane Seeps in the Black Sea: Environment-Forming and Ecological Role]. Sevastopol: ECOSI-Gidrofizika, 405 p. (in Russian).
  5. Lein, A.Yu. and Ivanov, M.V., 2009. Biogeochemical Cycle of Methane in the Ocean. Moscow: Nauka, 576 p. (in Russian).
  6. Malakhova, T.V., Kanapatskii, T.A., Egorov, V.N., Malakhova, L.V., Artemov, Yu.G., Evtushenko, D.B., Gulin, S.B. and Pimenov, N.V., 2015. Microbial Processes and Genesis of Methane Gas Jets in the Coastal Areas of the Crimean Peninsula. Microbiology, 84(6), pp. 838-845. https://doi.org/10.1134/S0026261715060053
  7. Malakhova, T.V., Egorov, V.N., Malakhova, L.V., Artemov, Yu. and Pimenov, N.V., 2020. Biogeochemical Characteristics of Shallow Methane Seeps of Crimean Coastal Areas in Comparison with Deep-Sea Seeps of the Black Sea. Marine Biological Journal, 5(4), pp. 37-55. https://doi.org/10.21072/mbj.2020.05.4.04 (in Russian).
  8. Leifer, I., 2019. A Synthesis Review of Emissions and Fates for the Coal Oil Point Marine Hydrocarbon Seep Field and California Marine Seepage. Geofluids, 2019(1), 4724587. https://doi.org/10.1155/2019/4724587
  9. Leifer, I. and MacDonald, I., 2003. Dynamics of the Gas Flux from Shallow Gas Hydrate Deposits: Interaction between Oily Hydrate Bubbles and the Oceanic Environment. Earth and Planetary Science Letters, 210(3–4), pp. 411-424. https://doi.org/10.1016/S0012-821X(03)00173-0
  10. Muyakshin, S.I. and Sauter, E., 2010. The Hydroacoustic Method for the Quantification of the Gas Flux from a Submersed Bubble Plume. Oceanology, 50(6), pp. 995–1001. https://doi.org/10.1134/S0001437010060202
  11. Sauter, E.J., Muyakshin, S.I., Charlou, J.-L., Schlüter, M., Boetius, A., Jerosch, K., Damm, E., Foucher, J.-P. and Klages, M., 2006. Methane Discharge from a Deep-Sea Submarine Mud Volcano into the Upper Water Column by Gas Hydrate-Coated Methane Bubbles. Earth and Planetary Science Letters, 243(3–4), pp. 354-365. https://doi.org/10.1016/j.epsl.2006.01.041
  12. Leifer, I., 2015. Seabed Bubble Flux Estimation by Calibrated Video Survey for a Large Blowout Seep in the North Sea. Marine and Petroleum Geology, 68(B), pp. 743-752. https://doi.org/10.1016/j.marpetgeo.2015.08.032
  13. Veloso, M., Greinert, J., Mienert, J. and De Batist, M., 2015. A New Methodology for Quantifying Bubble Flow Rates in Deep Water Using Splitbeam Echosounders: Examples from the Arctic Offshore NW-Svalbard. Limnology and Oceanography: Methods, 13(6), pp. 267-287. https://doi.org/10.1002/lom3.10024
  14. Leifer, I.D., Chernykh, D., Shakhova, N. and Semiletov, I., 2017. Sonar Gas Flux Estimation by Bubble Insonification: Application to Methane Bubble Flux from Seep Areas in the Outer Laptev Sea. The Cryosphere, 11(3), pp. 1333-1350. https://doi.org/10.5194/tc-11-1333-2017
  15. Leifer, I., 2010. Characteristics and Scaling of Bubble Plumes from Marine Hydrocarbon Seepage in the Coal Oil Point Seep Field. Journal of Geophysical Research: Oceans, 115(C11), C11014. https://doi.org/10.1029/2009JC005844
  16. Römer, M., Sahling, H., Pape, T., Bahr, A., Feseker, T., Wintersteller, P. and Bohrmann, G., 2012. Geological Control and Magnitude of Methane Ebullition from a High-Flux Seep Area in the Black Sea – the Kerch Seep Area. Marine Geology, 319–322, pp. 57-74. https://doi.org/10.1016/j.margeo.2012.07.005
  17. Malakhova, T.V., Budnikov, A.A., Ivanova, I.N., Khurchak, A.I., Khurchak, A.P. and Krasnova, E.A., 2024. Passive Acoustic Monitoring for Seabed Bubble Flows: Case of Shallow Methane Seeps at Laspi Bay (Black Sea). The Journal of the Acoustical Society of America, 156(6), pp. 4202-4216. https://doi.org/10.1121/10.0034605
  18. Malakhova, T.V., Makarov, M.M., Khurchak, A.I., Stetsiuk, A.P., Kucher, K.M., Syrbu, N.S., Legkodimov, A.A., Ivanov, M.V. and Budnikov, A.A., 2025. Shallow Gas Seeps Offshore Crimea (Black Sea): Mapping, Bubble Flow Quantification and Geochemical Study. Regional Studies in Marine Science, 89, 104290. https://doi.org/10.1016/j.rsma.2025.104290
  19. Malakhova, T.V., Murashova, A.I., Ivanova, I.N., Budnikov, A.A., Malakhova, L.V., Krasnova, E.A., Rylkova, O.A. and Pimenov, N.V., 2023. Environment-Forming Effect of Bubble Gas Emissions in the Golubaya Bay, Black Sea: Oxygen Regime and Bacterial Mats. Geochemistry International, 61(3), pp. 274-284. https://doi.org/10.1134/S0016702923030084
  20. Egorov, V.N., Plugatar, Y.V., Malakhova, T.V., Sadogursky, S.Y. and Moseichenko, I.N., 2018. Gas Seeps Detection in the Offshore Area near Cape Martyan. Bulletin of the State Nikitsky Botanical Gardens, 126, pp. 9-13. https://doi.org/10.25684/NBG.boolt.126.2018.01 (in Russian).
  21. Agarkova-Lyakh, I.V., 2015. Nature Complexes of the Coastal Zone of the Southern Coast of Crimea. Scientific Notes of the V.I. Vernadsky Crimean Federal University. Geography. Geology, 1 (3), pp. 42-58 (in Russian).
  22. Makarov, M.M., Muyakshin, S.I., Kucher, K.M., Aslamov, I.A. and Granin, N.G., 2020. A Study of the Gas Seep Istok in the Selenga Shoal Using Active Acoustic, Passive Acoustic and Optical Methods. Journal of Great Lakes Research, 46(1), pp. 95-101. https://doi.org/10.1016/j.jglr.2019.10.014
  23. Judd, A.G. and Hovland, M., 2007. Seabed Fluid Flow: The Impact on Geology, Biology and the Marine Environment. Cambridge: Cambridge University Press, 492 p.
  24. Chernykh, D.V., Salomatin, A.S., Yusupov, V.I., Shakhova, N.E., Kosmach, D.A., Dudarev, O.V., Gershelis, E.V., Silionov, V.I., Ananiev, R.A., Grinko, A.A. [et al.], 2021. Acoustic Investigations of the Deepest Methane Seeps in the Okhotsk Sea. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 332(10), pp. 57-68. https://doi.org/10.18799/24131830/2021/10/3286 (in Russian).
  25. Judd, A., Davies, G., Wilson, J., Holmes, R., Baron, G. and Bryden, I., 1997. Contributions to Atmospheric Methane by Natural Seepages on the UK Continental Shelf. Marine Geology, 137(1–2), pp. 165-189. https://doi.org/10.1016/S0025-3227(96)00087-4
  26. Greinert, J., McGinnis, D.F., Naudts, L., Linke, P. and De Batist, M., 2010. Atmospheric Methane Flux from Bubbling Seeps: Spatially Extrapolated Quantification from a Black Sea Shelf Area. Journal of Geophysical Research: Oceans, 115(C1), C01002. https://doi.org/10.1029/2009JC005381
  27. Leifer, I. and Patro, R.K., 2002. The Bubble Mechanism for Methane Transport from the Shallow Sea Bed to the Surface: A Review and Sensitivity Study. Continental Shelf Research, 22(16), pp. 2409–2428. https://doi.org/10.1016/S0278-4343(02)00065-1
  28. Krasnova, E.A., Budnikov, A.A., Ivanova, I.N., Khurchak, A.I., Gryaznova, A.S., Krylov, O.V. and Malakhova, T.V., 2024. Geological and Geochemical Characteristics of Hydrocarbon Seeps in the Continental Margin of Southwestern Crimea, Laspi Bay. Georesources, 26(4), pp. 83-100. https://doi.org/10.18599/grs.2024.4.13 (in Russian).
  29. Leifer, I., Luyendyk, B.P., Boles, J. and Clark, J.F., 2006. Natural Marine Seepage Blowout: Contribution to Atmospheric Methane. Global Biogeochemical Cycles, 20(3), GB3008. https://doi.org/10.1029/2005GB002668
  30. Leifer, I. and Boles, J., 2005. Turbine Tent Measurements of Marine Hydrocarbon Seeps on Subhourly Timescales. Journal of Geophysical Research: Oceans, 110(C1), C01006. https://doi.org/10.1029/2003JC002207
  31. Boles, J.R., Clark, J.F., Leifer, I. and Washburn, L., 2001. Temporal Variation in Natural Methane Seep Rate Due to Tides, Coal Oil Point Area, California. Journal of Geophysical Research: Oceans, 106(C11), pp. 27077-27086. https://doi.org/10.1029/2000JC00077
  32. Greinert, J., McGinnis, D.F., Naudts, L., Linke, P. and De Batist, M., 2010. Atmospheric Methane Flux from Bubbling Seeps: Spatially Extrapolated Quantification from a Black Sea Shelf Area. Journal of Geophysical Research: Oceans, 115(C1), C01002. https://doi.org/10.1029/2009JC005381
  33. Khortov, A.V., Rimskii-Korsakov, N.A., Pronin, A.A. and Mutovkin, A.D., 2023. Results of Seismostratigraphic Investigations of the Crimean Shelf by Continuous Seismoacoustic Profiling. Doklady Earth Sciences, 512, pp. 1044-1049. https://doi.org/10.31857/S2686739723601023
  34. Abrams, M.A., 2005. Significance of Hydrocarbon Seepage Relative to Petroleum Generation and Entrapment. Marine and Petroleum Geology, 22(4), pp. 457-477. https://doi.org/10.1016/j.marpetgeo.2004.08.003
  35. Bonini, M., 2007. Interrelations of Mud Volcanism, Fluid Venting, and Thrust-Anticline Folding: Examples from the External Northern Apennines (Emilia-Romagna, Italy). Journal of Geophysical Research: Solid Earth, 112(B8), B08413. https://doi.org/10.1029/2006JB004859
  36. Kravchenko, V.G., 2008. [Mechanism of Functioning of Underwater Gas Flares in the Black Sea]. Geology and Minerals of the World Ocean, 1(11), pp. 106-115 (in Russian).
  37. Whiticar, M.J., 2002. Diagenetic Relationships of Methanogenesis, Nutrients, Acoustic Turbidity, Pockmarks and Freshwater Seepages in Eckernförde Bay. Marine Geology, 182(1–2), pp. 29-53. https://doi.org/10.1016/S0025-3227(01)00227-4
  38. Malakhova, T.V., Ivanova, I.N., Budnikov, A.A., Murashova, A.I. and Malakhova, L.V., 2021. Distribution of Hydrological Parameters over the Methane Seep Site in the Golubaya Bay (the Black Sea): A Connection with Submarine Freshwater Discharge. Russian Meteorology and Hydrology, 46(11), pp. 792-798. https://doi.org/10.3103/S1068373921110091
  39. Damm, E., Ericson, Y. and Falck, E., 2021. Waterside Convection and Stratification Control Methane Spreading in Supersaturated Arctic Fjords (Spitsbergen). Continental Shelf Research, 224, 104473. https://doi.org/10.1016/j.csr.2021.104473

Files

Full text

JATS XML

We use Yandex Metrics. Read more.

Мы используем Яндекс Метрику. Подробнее.