Vertical Distribution of Phosphates in the Black Sea Based on the Expeditionary Data, 2016–2019

S. I. Kondratev✉, D. S. Khoruzhii

Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation

✉ e-mail: skondratt@mail.ru

Abstract

Purpose. The purpose of the study is to analyze the features of vertical distribution of phosphates and dissolved organic phosphorus (Porg) in the Black Sea at the present period.

Methods and Results. The data obtained by the scientists of Marine Hydrophysical Institute in the Black Sea within the economic zone of Russia in 2016–2019 were used. At more than 200 deep-sea stations, a cassette of 12 bathometers (the Seabird-Electronics STD-instrument) was applied for taking hydrochemical samples at certain isopycnic surfaces, usually at σt = 16.30; 16.25; 16.20; 16.20; 16.15; 16.10; 16.05; 16.00; 15.95; 15.90; 15.80; 15.50, 14.0 kg/m3. At the coastal shallow-water stations, samples were taken at the 10 m intervals. Such a scheme permitted to carry out vertical sampling in the upper mixed layer and in the suboxic zone (including its upper boundary) with possible minimum of phosphates, to determine the depth of hydrogen sulfide formation and the location of the phosphates concentration maximum in the upper part of the anaerobic zone.

Conclusions. From the surface to isopycn σt = 14.4 kg/m3, the content of phosphates and Porg does not exceed 0.1 µM; below this isopycnic surface, the phosphates concentration begins to increase, whereas of Porg remains at the same level. At all the profiles of the phosphates vertical distribution, the phosphates concentration minimum was recorded near the isopycnic surface σt = 15.8 kg/m3, and its maximum – near the isopycnic surface σt = 16.2 kg/m3. The minimum content of phosphates varied within 0–1.5 µM; in 2016–2017 the phosphates concentration maximum did not exceed 8 µM; in 2018, in many cases, it was higher than 12 µM, and once, near the Kerch Strait, it exceeded 17 µM. Increase in the magnitude of the maximum phosphates concentration (in the previous studies in 1988–2013, it did not exceed 8 µM) is assumed to be related to installation of the supports for constructing the Kerch Bridge.

Keywords

Black Sea, hydrogen sulfide formation, nutrients, vertical distribution of phosphates, field data

Acknowledgements

The investigation was carried out within the framework of the state task on theme No. 0555-2021-0004 “Fundamental studies of the oceanological processes which determine the state and evolution of the marine environment influenced by natural and anthropogenic factors, based on the observation and modeling methods”.

Original russian text

Original Russian Text © S. I. Kondratev, D. S. Khoruzhii, 2021, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 37, Iss. 5, pp. 579-590 (2021)

For citation

Kondratev, S.I. and Khoruzhii, D.S., 2021. Vertical Distribution of Phosphates in the Black Sea Based on the Expeditionary Data, 2016–2019. Physical Oceanography, 28(5), pp. 538-548. doi:10.22449/1573-160X-2021-5-538-548

DOI

10.22449/1573-160X-2021-5-538-548

References

  1. Dijkstra, N., Kraal, P., Kuypers, M.M.M., Schnetger, B. and Slomp, C.P., 2014. Are Iron-Phosphate Minerals a Sink for Phosphorus in Anoxic Black Sea Sediments? PLoS ONE, 9(7), е101139. https://doi.org/10.1371/journal.pone.0101139
  2. Kraal, Р., Yücel, М. and Slomp, С.Р., 2019. Turbidite Deposition and Diagenesis in the Southwestern Black Sea: Implications for Biogeochemical Cycling in an Anoxic Basin. Marine Chemistry, 209, pp. 48-61. doi:10.1016/j.marchem.2019.01.001
  3. Gordey, A.S. and Chechueva, N.S., 2019. Hydrochemical Conditions in the South-Eastern Part of the Baltic Sea in 2018. Proceedings of Moscow Institute of Physics and Technology, 11(4), pp. 68-81 (in Russian).
  4. Scranton, M.I., Taylor, G.T., Thunell, R., Benitez-Nelson, C.R., Muller-Karger, F., Fanning, K., Lorenzoni, L., Montes, E., Varela, R. and Astor, Y., 2014. Interannual and Subdecadal Variability in the Nutrient Geochemistry of the Cariaco Basin. Oceanography, 27(1), pp. 148-159. http://dx.doi.org/10.5670/oceanog.2014.18
  5. Pakhomova, S., Braaten, H.F.V., Yakushev, E. and Skei, J., 2014. Biogeochemical Consequences of an Oxygenated Intrusion into an Anoxic Fjord. Geochemical Transactions, 15, 5. doi:10.1186/1467-4866-15-5
  6. Murray, J.W., Ed., 1991. Black Sea Oceanography: Results from the 1988 Black Sea Expedition. Deep Sea Research Part A. Oceanographic Research Papers, 38(Suppl. 2), pp. S655–S1266.
  7. Konovalov, S.K. and Murray, J.W., 2001. Variations in the Chemistry of the Black Sea on a Time Scale of Decades (1960–1995). Journal of Marine Systems, 31(1–3), pp. 217-243. doi:10.1016/S0924-7963(01)00054-9
  8. Murray, J.W., 2005. Special Issue on Black Sea Oceanography. Oceanography, 18(2), pp. 14-15. https://doi.org/10.5670/oceanog.2005.37
  9. Konovalov, S.K. and Eremeev, V.N., 2012. [Regional Features, Stability, and Evolution of Biochemical Structure of the Black Sea Waters]. In: V. N. Eremeev, S. K. Konovalov, Eds., 2012. [Stability and Evolution of Oceanological Characteristics of the Black Sea Ecosystems]. Sevastopol: ECOSI-Gidrofizika, pp. 273-299 (in Russian).
  10. Eremeeva, L.V., Romanov, A.S., Ovsjanyj, E.I., Dolotov, V.V. and Konovalov, S.K., 1995. [Hydro-Chemical Studies in the 33rd Cruise of R/V "Professor Kolesnikov"]. Preprint. Sevastopol: MHI, 43 p. (in Russian).
  11. Krastev, A., Shtereva, G., Hristova, O. and Dzhurova, B., 2006. Nutrients in the Western Black Sea Area. Spatial and Vertical Distribution. In: Commission on the Protection of the Black Sea against Pollution, 2006. Proceedings of the First Biannual Scientific Conference: Black Sea Ecosystem 2005 and Beyond. Istanbul, Turkey, pp. 93-105.
  12. Kontrat’ev, S.I., Romanov, A.S. and Vnukov, Yu.L., 2007. Peculiarities of Distribution of Hydrochemical Characteristics in the Region of the Continental Slope of the Northwestern Black Sea. Morskoy Gidrofizicheskiy Zhurnal, (5), pp. 69-79 (in Russian).
  13. Tuğrul, S., Murray, J.W., Friederich, G.E. and Salihoğlu, İ., 2014. Spatial and Temporal Variability in the Chemical properties of the Oxic and Suboxic Layers of the Black Sea. Journal of Marine Systems, 135, pp. 29-43. https://doi.org/10.1016/j.jmarsys.2013.09.008
  14. Schulz-Vogt, H.N., Pollehne, F., Jürgens, K., Arz, H.W., Beier, S., Bahlo, R., Dellwig, O., Henkel, J.V., Herlemann, D.P.R., Krüger, S., Leipe, T. and Schott, T., 2019. Effect of Large Magnetotactic Bacteria with Polyphosphate Inclusions on the Phosphate Profile of the Suboxic Zone in the Black Sea. The ISME Journal, 13, pp. 1198-1208. https://doi.org/10.1038/s41396-018-0315-6
  15. Shnyukov, E.F., Goryachkin, J.N. and Kondratyev, S.I., 2006. Hydrogen Sulphide, Phosphates and Silicic Acid in the Bottom Waters of the Black Sea near Mud Volcanoes. Geology and Mineral Resources of World Ocean, (1), pp. 55-64.
  16. Grasshoff, K., Ehrhardt, M. and Kremling, K., Eds., 1983. Methods of Seawater Analysis. Weinheim: Verlag Chemie, 419 p.
  17. Baskakova, T.E., Kosenko, Yu.V. and Burdina, E.I., 2019. Spatio-Temporal Features of the Nutrients Dynamics in the Northeastern Black Sea. Aquatic Bioresources & Environment, 2(1), pp. 7-19. doi:10.47921/2619-1024_2019_2_1_7 (in Russian).
  18. Shaffer, G., 1986. Phosphate Pumps and Shuttles in the Black Sea. Nature, 321(6069), pp. 515-517. https://doi.org/10.1038/321515a0
  19. Delwig, O., Leipe, T., März, C., Glockzin, M., Pollehne, F., Schnetger, B., Yakushev, E.V., Bötcher, M.E. and Brumsack, H.-J., 2010. A New Particulate Mn-Fe-P-Shuttle at the Redoxcline of Anoxic Basins. Geochimica et Cosmochimica Acta, 74(24), pp. 7100-7115. https://doi.org/10.1016/j.gca.2010.09.017
  20. Jilbert, T. and Slomp, C.P., 2013. Iron and Manganese Shuttles Control the Formation of Authigenic Phosphorus Minerals in the Euxinic Basins of the Baltic Sea. Geochimica et Cosmochimica Acta, 107, pp. 155-169. https://doi.org/10.1016/j.gca.2013.01.005
  21. Hermans, M., Lenstra, W.K., van Helmond, N.A.G.M., Behrends, T., Egger, M., Seguret, M.J.M., Gustafsson, E., Gustafsson, B.G. and Slomp, C.P., 2019. Impact of Natural Re-Oxygenation on the Sediment Dynamics of Manganese, Iron and Phosphorus in a Euxinic Baltic Sea Basin. Geochimica et Cosmochimica Acta, 246, pp. 174-196. https://doi.org/10.1016/j.gca.2018.11.033
  22. Lenstra, W.K., Séguret, M.J.M., Behrends, T., Groeneveld, R.K., Hermans, M., Witbaard, R. and Slomp, C.P., 2020. Controls on the Shuttling of Manganese over the Northwestern Black Sea shelf and Its Fate in the Euxinic Deep Basin. Geochimica et Cosmochimica Acta, 273, pp. 177-204. https://doi.org/10.1016/j.gca.2020.01.031
  23. Ivanov, V.A. and Belokopytov, V.N., 2013. Oceanography of the Black Sea. Sevastopol: ECOSI-Gidrofizika, 210 p. Available at: https://www.researchgate.net/publication/236853664_Ivanov_VA_Belokopytov_VN_Oceanography_of_the_Black_Sea_National_Academy_of_Sciences_of_Ukraine_Marine_Hydrophysical_Institute_Sevastopol_210_p [Accessed: 06 September 2021].

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