Features of Methane Distribution in the Euphotic Layer of the Northern Black Sea in Summer, 2018 (Based on the Data of the 102nd Cruise of R/V "Professor Vodyanitsky")

T. V. Malakhova1, ✉, I. M. Mansurova1, L. V. Malakhova1, N. V. Minina1, A. D. Zagovenkova2

1 A.O. Kovalevsky Institute of Biology of the Southern Seas, Russian Academy of Sciences, Sevastopol, Russian Federation

2 M.V. Lomonosov Moscow State University, Moscow, Russian Federation

✉ e-mail: t.malakhova@imbr-ras.ru

Abstract

Purpose. The main goal of the work was to assess the horizontal and vertical structure of methane (CH4) distribution, its emission to the atmosphere in the euphotic zone of the northern part of the Black Sea in summer, 2018 as well as to reveal its relationship with the chlorophyll a concentration.

Methods and Results. The CH4 concentration in the surface layer was determined by the gas chromatographic method at 104 stations, including 45 stations at which the vertical profiles of the CH4 content in the upper 0–50 m layer were done. The chlorophyll a concentration was defined by the fluorometric method. The CH4 distribution in this region showed distinct spatial heterogeneity. The concentration of the dissolved in the surface water CH4 varied within 0–39.2 nmol/l at all the stations. The average calculated value of the CH4 seawater-air flux was 2.3 nmol/m2/day, and the average CH4 saturation of surface water – 460 %. The major part of the sea area under study represented a source of methane emission to the atmosphere near-water layers, except for 15 stations where the CH4 concentration in the surface layer was smaller than its equilibrium values. The calculated integral value of the CH4 flux from the whole region under study (its area is equal to 88·103 km2) constituted 3.2 tons of CH4 per day. Vertical distribution of CH4 in the upper 50 m layer was different in the coastal and deep-sea areas. At the deep-sea stations, the maximum values were revealed in the sub-surface layers, whereas at the coastal stations (not deeper than 100 m), the highest CH4 concentrations, up to 86 nmol /l, were observed mainly at the near-bottom horizons..

Conclusions. The average concentration of CH4 in the deep-sea profiles was 2 times lower than that in the coastal ones. Sub-surface maximums of the CH4 concentration coincided in general with the maximums of the chlorophyll a concentration. It was also found that the CH4 highest concentration corresponded to the increased chlorophyll a content (0.58 mg/m3) in the Feodosiya Gulf surface water. The abnormally high concentration of CH4 (269 nmol /l) at the bottom horizon, by an order of magnitude exceeding the average methane content in the adjacent areas, was revealed at the station near the Dnieper paleo-channel. Such an increased concentration is assumed to be caused by the methane emission from the gas seeps densely located in this region.

Keywords

methane, emission, chlorophyll a, euphotic layer, Black Sea

Acknowledgements

The authors are thankful to the crew of the R/V Professor Vodyanitsky for their assistance in conducting the outboard works during the 102nd cruise, to I.G. Sidorov and V.Yu. Proskurnin for their help in sampling and analysis, to the staff of Marine Hydrophysical Institute for providing hydrological data, as well as to the reviewer for his constructive comments. The investigation was carried out within the framework of the state task on the themes “Molismological and biogeochemical fundamentals of homeostasis of marine ecosystems” No AAAA-A18-118020890090-2 and “Functional, metabolic and toxicological aspects of existence of hydrobionts and their populations in biotopes with different physicochemical conditions” No AAAA-A18-118021490093-4.

Original russian text

Original Russian Text © T. V. Malakhova, I. M. Mansurova, L. V. Malakhova, N. V. Minina, A. D. Zagovenkova, 2020, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 36, Iss. 2, pp. 186–201 (2020)

For citation

Malakhova, T.V., Mansurova, I.M., Malakhova, L.V., Minina, N.V. and Zagovenkova, A.D., 2020. Features of Methane Distribution in the Euphotic Layer of the Northern Black Sea in Summer, 2018 (Based on the Data of the 102nd Cruise of R/V "Professor Vodyanitsky"). Physical Oceanography, 27(2), pp. 171-185. doi:10.22449/1573-160X-2020-2-171-185

DOI

10.22449/1573-160X-2020-2-171-185

References

  1. Bakker, D.C.E., Bange, H.W., Gruber, N., Johannessen, T., Upstill-Goddard, R.C., Borges, A.V., Delille, B., Löscher, C.R., Naqvi, S.W.A., Omar, A.M. and Santana-Casiano, J.M. 2014. Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate. In: L. Peter and M.T. Johnson, Eds., 2014. Ocean-Atmosphere Interactions of Gases and Particles. Berlin, Heidelberg: Springer, pp. 113-169. https://doi.org/10.1007/978-3-642-25643-1_3
  2. 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).
  3. Lein, A.Yu. and Ivanov, M.V., 2009. Biogeochemical Cycle of Methane in the Ocean. Moscow: Nauka, 576 p. (in Russian).
  4. Sovga, E.E., Lyubartseva, S.P. and Lyubitsky, A.A., 2008. Investigation of the Biogeochemistry of Methane and Mechanisms of Its Transfer in the Black Sea. Physical Oceanography, 18(5), pp. 272-287. https://doi.org/10.1007/s11110-009-9024-z
  5. Amouroux, D., Roberts, G., Rapsomanikis, S. and Andreae, M.O., 2002. Biogenic Gas (CH4, N20, DMS) Emission to the Atmosphere from Near-Shore and Shelf Waters of the North-Western Black Sea. Estuarine, Coastal and Shelf Science, 54(3), pp. 575-587. https://doi.org/10.1006/ecss.2000.0666
  6. Rusanov, I.I., Lein, A.Yu., Pimenov, N.V., Yusupov, S.K. and Ivanov, M.V., 2002. The Biogeochemical Cycle of Methane on the Northwestern Shelf of the Black Sea. Microbiology, 71(4), pp. 479-487. https://doi.org/10.1023/A:1019862014508
  7. Egorov, A.V., 2002. Some Features of Methane Water Column Distribution in the Northeastern Part of the Black Sea. In: A.G. Zatsepin and M.V. Flint, eds., 2002. Multidisciplinary Investigations of the Northeast Part of the Black Sea. Moscow: Nauka, pp. 183-190 (in Russian).
  8. Scranton, M.I. and Farrington, J.W., 1977. Methane Production in the Waters off Walvis Bay. Journal of Geophysical Research, 82(31), pp. 4947-4953. https://doi.org/10.1029/JC082i031p04947
  9. Oremland, R.S., 1979. Methanogenic Activity in Plankton Samples and Fish Intestines a Mechanism for In Situ Methanogenesis in Oceanic Surface Waters. Limnology and Oceanography, 24(6), pp. 1136-1141. https://doi.org/10.4319/lo.1979.24.6.1136
  10. Sieburth, J.M. and Donaghay, P.L., 1993. Planktonic Methane Production and Oxidation within the Algal Maximum of the Pycnocline: Seasonal Fine-Scale Observations in an Anoxic Estuarine Basin. Marine Ecology-Progress Series, 100, pp. 3-15. doi:10.3354/meps100003
  11. Marty, D.G., 1993. Methanogenic Bacteria in Seawater. Limnology and Oceanography, 38(2), pp. 452-456. https://doi.org/10.4319/lo.1993.38.2.0452
  12. Pimenov, N.V., Rusanov, I.I., Yusupov, S.K., Fridrich, J., Lein, A.Yu, Wehrli, B. and Ivanov, M.V., 2000. Microbial Processes at the Aerobic-Anaerobic Interface in the Deep- Water Zone of the Black Sea. Microbiology, 69(4), pp. 436-448. https://doi.org/10.1007/BF02756769
  13. Rusanov, I.I., 2007. [Mikrobial Biogeochemistry of Methane Cycle in the Deep Area of the Black Sea. Diss. Abstract kand. biol. nauk.]. Moscow, 24 p. (in Russian).
  14. Keller, M.D., Belows W.K. and Guillard, R.R.L., 1989. Dimethyl Sulfide Production in Marine Phytoplankton. In: E. S. Saltzman, W. J. Cooper, eds., 1989. Biogenic Sulfur in the Environment. Washington, DC: American Chemical Society, Chapter 11, pp. 167-182. doi:10.1021/bk-1989-0393.ch011
  15. Althoff, F., Benzing, K., Comba, P., McRoberts, C., Boyd, D.R., Greiner, S. and Keppler, F., 2014. Abiotic Methanogenesis from Organosulphur Compounds under Ambient Conditions. Nature Communications, 5, 4205. https://doi.org/10.1038/ncomms5205
  16. Damm, E., Thoms, S., Beszczynska-Möller, A., Nöthig, E. M. and Kattner, G., 2015. Methane Excess Production in Oxygen-Rich Polar Water and a Model of Cellular Conditions for This Paradox. Polar Science, 9(3), pp. 327-334. https://doi.org/10.1016/j.polar.2015.05.001
  17. Lenhart, K., Klintzsch, T., Langer, G., Nehrke, G., Bunge, M., Schnell, S. and Keppler, F., 2015. Evidence for Methane Production by Marine Algae (Emiliana huxleyi) and its Implication for the Methane Paradox in Oxic Waters. Biogeosciences Discussions, 12(24), pp. 20323-20360. doi:10.5194/bgd-12-20323-2015
  18. Bogard, M.J., del Giorgio, P.A., Boutet, L., García‐Chaves, M.C., Prairie, Y.T., Merante, A. and Derry, A.M., 2014. Oxic Water Column Methanogenesis as a Major Component of Aquatic CH 4 Fluxes. Nature Communications, 5, 5350. doi:10.1038/ncomms6350
  19. Borges, A.V., Speeckaert, G., Champenois, W., Scranton, M.I. and Gypens, N., 2018. Productivity and Temperature as Drivers of Seasonal and Spatial Variations of Dissolved Methane in the Southern Bight of the North Sea. Ecosystems, 21(4), pp. 583-599. doi:10.1007/s10021-017-0171-7
  20. Bolshakov, A.M. and Egorov, A.V., 1987. On the Application of Phase Equilibrium Degasing Method for Gasometric Investigation. Okeanologiya, 27(5), pp. 861–862 (in Russian).
  21. Wanninkhof, R., 2014. Relationship between Wind Speed and Gas Exchange over the Ocean Revisited. Limnology and Oceanography: Methods, 12(6), pp. 351-362. doi:10.4319/lom.2014.12.351
  22. Wiesenburg, D.A. and Guinasso Jr, N.L., 1979. Equilibrium Solubilities of Methane, Carbon Monoxide, and Hydrogen in Water and Sea Water. Journal of Chemical and Engineering Data, 24(4), pp. 356-360. doi:10.1021/je60083a006
  23. Jeffrey, S.W., Mantoura, R.F.C. and Wright, S.W., eds., 2005. Phytoplankton Pigments in Oceanography: Guidelines to Modern Methods. Paris: UNESCO Publishing, 661 p.
  24. Vityuk, D.M., 1983. Suspended Matter and its Biogenic Components. Kiev: Naukova Dumka, 212 p. (in Russian).
  25. Belokopytov, V.N., 1998. "Oceanographer": Applied Software for Oceanographic Surveys. In: NIO, 1998. International Symposium on Information Technology in Oceanography (ITO-98): Abstracts. Goa, India, 12-16 October 1998. Goa, p. 79.
  26. Finenko, Z.Z., Churilova, T.Ya. and Lee R.I., 2005. Dynamics of the Vertical Distributions of Chlorophyll and Phytoplankton Biomass in the Black Sea. Oceanology, 45(suppl.1), pp. S112-S126. Available at: https://www.researchgate.net/publication/286014069 [Accessed: 07 June 2019].
  27. Churilova, T., Suslin, V., Sosik, H.M., Efimova, T., Moiseeva, N., Moncheva, S., Mukhanov, V., Rylkova, O. and Krivenko, O., 2019. Phytoplankton Light Absorption in the Deep Chlorophyll Maximum Layer of the Black Sea. European Journal of Remote Sensing, 52(suppl.1), pp. 123-136. https://doi.org/10.1080/22797254.2018.1533389
  28. Malakhova, T.V., Malakhova, L.V., Budnikov, A.A. and Ivanova, I.N., 2020. Spatio- Temporal Dynamics of Methane Content in the Sevastopol Bay and Its Emission to the Atmosphere. Vestnik Moskovskogo Universiteta. Seria 5, Geografia, (3), pр. 73–80 (in Russian).
  29. Sommer, S., Schmidt, M. and Linke, P., 2015. Continuous Inline Mapping of a Dissolved Methane Plume at a Blowout Site in the Central North Sea UK Using a Membrane Inlet Mass Spectrometer – Water Column Stratification Impedes Immediate Methane Release into the Atmosphere. Marine and Petroleum Geology, 68(part B), pp. 766-775. doi:10.1016/j.marpetgeo.2015.08.020
  30. Malakhova, T.V. and Mansurova, I.M., 2018. The Relationship between Methane and Chlorophyll a in the Water of the Euphotic Zone of the Black Sea Shelf. In: Lomonosov MSU branch in Sevastopol, 2018. [ECOBIO-2018: Collection of Proceedings of the 5th Scientific Practical Youth Conference "Ecobiological Problems of the Azov and Black Sea Area and Compehensive Biological Resource Management" (October 8–11, 2018)]. Sevastopol, 8-11 October 2018. Sevastopol: Lomonosov MSU branch in Sevastopol, pp. 186-189 (in Russian).

Download the article (PDF)