Climate  trend  assessment  of  pH  value  in the surface water of the open part of the Black Sea taking into account the limited observational data

A.B. Polonsky, E.A. Grebneva

Institute of Natural and Technical Systems, RF, Sevastopol, Lenin St., 28


DOI: 10.33075/2220-5861-2023-3-27-41

UDC 551.464.6/465.7(262.5)                                                                                     


Based on archival observations of pH values in the period from 1977 to 1996 and data of expeditionary studies carried out over the period 2019 -2022, the climate trend of the pH value in the surface waters of the open part of the Black Sea is assessed. Under the conditions of limited and spatio-temporal heterogeneity of the available observational data, in order to minimize the error in calculating the trend, a methodology taking into account the patterns of the spatial distribution and intra-annual variation of the pH value for surface waters of the deep-water part of the Black Sea is developed. According to the methodology, at the first step, with the asynchrony of the survey data, a correction was made for the intra-annual dynamics of the pH value in the deep part of the Black Sea. After the first correction of the pH values, at the second step, a correction was carried out taking into account the spatial heterogeneity of the pH field and the lack of observations of the pH value during the survey period in a significant part of the deep-water area of the sea. Further, it was determined that two samples (namely, samples of archival data and expeditionary measurements) belong to the same general totality. Thus, according to the available combined data on the pH value, it is possible to obtain representative statistical estimates, including the calculation of the trend value. The linear trend calculated by the standard least squares method turned out to be significant. The significance level of the trend was determined by Student’s t-test (at p=0.05). As a result, it was found that the trend of changes in pH values in the surface layer of the deep-water area of the Black Sea is close to the trends observed in other regions of the open parts of the World Ocean, slightly exceeding them in absolute value. The pH values in the surface waters of the inland sea decreased in the period from 1977 to 2022 at an average rate of about 0.024 pH units/10 years.

Keywords: deep-water part of the Black Sea, surface layer, pH value, spatial and temporal inhomogeneity of pH data, pH climate trend.

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  1. Terhaar J., Frölicher T., and Joos F. Ocean acidification in emission-driven temperature stabilization scenarios: the role of TCRE and non-CO2 greenhouse gases. Environmental Research Letters, 2023, Vol. 18, pp. 24–33.
  2. Gattuso J.-P. and Hansson L. Ocean acidification: background and history. Ocean Acidification. Oxford University Press, Oxford, 2011, pp. 1–20.
  3. Gattuso J.-P., Magnan A., Billé R., Cheung W. W. L., Howes E. L., Joos F., Allemand D., Bopp L., Cooley S. R., Eakin C. M., Hoegh-Guldberg O., Kelly R. P., Pörtner H.-O., Rogers A. D., Baxter J. M., Laffoley D., Osborn D., Rankovic A., Rochette J., Sumaila U. R., Treyer S., and Turley C. Contrasting futures for ocean and society from different anthropogenic CO₂ emissions scenarios. Science, 2015, Vol. 349, No. 6243, pp. aac4722.
  4. Schulz K.G., Barcelos E., Ramos J., Zeebe R.E., and Riebesell U. CO2 perturbation experiments: similarities and differences between dissolved inorganic carbon and total alkalinity manipulations. Biogeosciences, 2009, Vol. 6, pp. 2145–2153.
  5.  Quéré Le.C., Andrew R.M., Friedlingstein P., Sitch S., Hauck J., Pongratz J., Pickers P.A., Korsbakken J.I., Peters G., Canadell J.G., et al. Carbon Budget 2018. Earth System Science Data Discussions, 2018, No. 10 (4), pp. 2141–2194.
  6. Okutan V. Connection between Ocean Acidification and Sound Propagation. International Journal of Environment and Geoinformatics, 2015, No. 2 (2), pp. 16–26.
  7. Gazioğlu C. and Okutan V. Underwater Noise Pollution at the Strait of Istanbul (Bosphorus). International Journal of Environment and Geoinformatics, 2016, No. 3 (3), pp. 26–39.
  8. (January 29, 2023).
  9. Leseurre C., Monaco Cl. Lo, Reverdin G., Metzl N., Fin J., Olafsdottir S., and Racapé V. Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017). Biogeosciences, 2020, No. 17, pp. 2553–2577.
  10. Orr J.C., Fabry V.J., Aumont O., Bopp L., Doney S.C., Feely R.A., Gnanadesikan A., Gruber N., Ishida A., Joos F., et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature, 2005, Vol. 437, pp. 681–686.
  11. Andersson A.J., Mackenzie F.T., and Bates N.R. Life on the margin: implications of ocean acidification on Mg-calcite, high latitude and cold-water marine calcifiers. Marine Ecology Progress Series, 2008, Vol. 373, pp. 265–273.
  12. Ries J.B. Skeletal mineralogy in a high-CO2 world. Journal of Experimental Marine Biology and Ecology, 2011, Vol. 403, pp. 54–64.
  13. Polonsky A. Had Been Observing the Acidification of the Black Sea Upper Layer in XX Century? Turkish Journal of Fisheries and Aquatic Sciences, 2012, Vol. 12, pp. 391–396.
  14. Elge M. Analysis of Black Sea Ocean Acidification. International Journal of Environment and Geoinformatics, 2021, No. 8 (4), pp. 467–474.
  15. Polonsky A.B. and Grebneva E.A. The spatiotemporal variability of pH in waters of the Black Sea. Doklady Earth Sciences, 2019, No. 486 (2), pp. 669–674.
  16. Skopintsev B.A. Formirovaniye sovremennogo khimicheskogo sostava vody Chernogo morya (Formation of the modern chemical composition of the Black Sea water), Leningrad: Gidrometeoizdat, 1975, 336 p.
  17. Mel’nikov V.V., Polonskiy A.B., Kotolupova A.A., Grebneva E.A., Mel’nik L.A., and Biryukova M.A. GIS Instituta prirodno-tekhnicheskikh system (GIS of the Institute of Natural and Technical Systems). Sistemy kontrolya okruzhayushchey sredy, 2016, No. 4 (24), pp. 49–55.
  18. Polonskiy A.B. and Grebneva E.A. O mezhgodovoy izmenchivosti velichiny rH v poverkhnostnom sloye glubokovodnoy chasti Chernogo morya (On the interannual variability of the pH value in the surface layer of the deep-water part of the Black Sea). Sistemy kontrolya okruzhayushchey sredy, 2022. No. 2 (48), pp. 12–21.
  19. Novikova A.M., Kashirina Ye.C., Novikov A.A., Polonskiy A.B., and Pankeyeva T.V. GIS v morskikh issledovaniyakh: mirovoy opyt i vozmozhnosti yego primeneniya na primere Chernomorskogo regiona (GIS in marine research: world experience and possibilities of its application on the example of the Black Sea region), Proceedings of the Karadag Scientific Station. T.I. Vyazemsky – natural reserve of the Russian Academy of Sciences, 2017, No. 1 (3), pp. 54–66.
  20. Mal’tsev K.A. and Mukharamova S.S. Postroyeniye modeley prostranstvennykh peremennykh (s primeneniyem paketa Surfer) (Building models of spatial variables (using the Surfer package)), Kazan: Kazanskiy universitet, 2014, 103 p.
  21. Ryabinin A.I. and Shibayeva S.A. Instrumental’nyye metody analiza v ekologii (Instrumental methods of analysis in ecology), Sevastopol’: SIYAEiPyu, 2022, 168 p.
  22. Mann H. B. and Whitney D. R.On a test of whether one of two random variables is stochastically larger than the other.  Annals of Mathematical Statistics, 1947, No. 18, pp. 50–60.
  23. Afanas’yev V.N. and Yuzbashev M.M. Analiz vremennykh ryadov i prognozirovaniye (Time series analysis and forecasting), Moscow: INFRA-M, 2010, 320 p.
  24. Kharkov O.A. and Soloviev A.G. Statisticheskiye metody i matematicheskoye modelirovaniye (Statistical methods and mathematical modeling), Arkhangelsk: SGMU, 2017, 164 p.
  25. www.seadatanet.maris2nl (March 01, 2023).
  26. Polonskiy A.B. and Grebneva E.A. Vliyaniye Vostochno-atlanticheskogo kolebaniya na anomalii pH v verkhnem sloye otkrytoy chasti Chernogo morya (Effect of the East Atlantic Oscillation on pH Anomalies in the Upper Layer of the Open Part of the Black Sea). Sistemy kontrolya okruzhayushchey sredy, 2023, No. 1 (51), pp. 13–24.
  27. Bogatova Yu.I. Gidrokhimicheskiy rezhim ukrainskogo uchastka vzmor’ya Dunaya (Hydrochemical regime of the Ukrainian section of the Danube coast). Vodnyye resursy, 2013, Vol. 40, No. 3, pp. 295–305.
  28. Gazetov E.I. and Medinets V.I. Issledovaniye izmenchivosti osnovnykh fiziko-khimicheskikh kharakteristik morskikh vod vblizi ostrova Zmeinyy v 2004-2013 gg. (Study of the variability of the main physical and chemical characteristics of sea waters near Zmeiny Island in 2004-2013). Visnyk ONU. Ser.: Heohrafichni ta heolohichni nauky, 2016, Vol. 21, No. 2, pp. 24–45.
  29. Makkaveyev P.N., Polukhin A.A., and Stepanova S.V. Raboty po izucheniyu priust’yevykh oblastey malykh i srednikh rek v pribrezhnoy zone rossiyskogo sektora Chernogo morya (Works on the study of the mouth areas of small and medium-sized rivers in the coastal zone of the Russian sector of the Black Sea). Ekologicheskaya bezopasnost’ pribrezhnoy i shel’fovoy zon i kompleksnoye ispol’zovaniye resursov shel’fa, 2013, No. 27, pp. 412–417.
  30. Nesterova D.A. Razvitiye nepudmeu Exuviella cordata i yavleniye “krasnogo priliva” v severo-zapadnoy chasti Chernogo morya (Development of nepudmeu Exuviella cordata and the “red tide” phenomenon in the northwestern part of the Black Sea). Biologiya morya, 1979, No. 5, pp. 24–29.