Physical Oceanography Physical Oceanography 1573-160X 20230406 Experimental and field research Research Article Physical and Chemical Characteristics of the Near-Bottom and Pore Waters, and the Bottom Sediments in the Northeastern Part of the Black Sea Shelf https://orcid.org/0000-0003-3460-9650 L-7895-2017 Gurov K. I.
Russian Federation
gurovki@gmail.com https://orcid.org/0000-0002-9826-4789 AAB-5628-2019 Gurova Yu. S.
Russian Federation
kurinnaya-jul@yandex.ru https://orcid.org/0000-0002-1387-970X I-1755-2017 35784884700 Orekhova N. A.
Russian Federation
natalia.orekhova@mhi-ras.ru Marine Hydrophysical Institute of RAS Sevastopol Russian Federation 31 08 2023 30 4 454 467 22 09 2022 29 11 2022 26 04 2023 Copyright ©; 2023, K. I. Gurov, Yu. S. Gurova, N. A. Orekhova 2023 K. I. Gurov, Yu. S. Gurova, N. A. Orekhova https://creativecommons.org/licenses/by-nc/4.0/ https://physical-oceanography.ru/repository/issues/2023/04/06/

Purpose. The investigation is purposed at studying the features of the vertical distribution of geochemical parameters and chemical profile of pore waters in bottom sediments in the coastal zone of the northeastern part of the Black Sea.

Methods and Results. 24 samples of the bottom sediments surface layer were obtained in three cruises on the R/V "Professor Vodyanitsky" in September 2018, July 2019 and August 2021. 5 samples of cores and 9 samples of water from the near-bottom layer were taken in August 2021. The profiles of vertical distribution of oxygen and hydrogen sulfide, the iron oxidized and reduced forms in pore waters, and also oxygen concentration and the degree of oxygen-saturation of the near-bottom waters were studied; the geochemical characteristics of bottom sediments in the surface layer (0–5 cm) and in the cores were also determined. It was noted that the sediments surface layer in the northeastern region was formed by a silty material, the maximum portion of which (83–97%) was recorded in the areas where large rivers of the Krasnodar region flowed into the sea. In the sediments surface layer, the Corg content varied within 0.2–1.9% dry mass. The vertical distribution of Corg in the bottom sediments cores is characterized by a tendency to decrease in its content with depth; its maximum concentrations were observed in the upper (0–4 cm) layer.

Conclusions. It is established that in the area under study, the sediments upper layer is characterized by the aerobic conditions (oxygen penetrated up to 10 mm); in the sediments, the organic matter is oxidized mainly with the participation of iron (Fe(II, III)), that leads to developing the suboxic conditions. In some areas, the redox conditions in the sediments changed from suboxic (the region of Anapa and the area between the cities of Gelendzhik and Tuapse) to anoxic (the region of Novorossiysk and Tuapse), that is conditioned by occurrence of the sulfur reduced forms in the bottom sediments layer. It has been revealed that in the northeastern part of the Black Sea, the distribution of Fe(II, III) in the pore waters of bottom sediments is inversely proportional to the distribution of pH value (the correlation coefficients are –0.68 and –0.73, respectively).

 bottom sediments pore waters oxygen voltammetry granulometric composition organic carbon Black Sea The study was carried out within the framework of the state assignment on themes FNNN-2021-0004 "Fundamental studies of oceanological processes which determine the state and evolution of the marine environment influenced by natural and anthropogenic factors, based on observation and modeling methods", FNNN-2021-0005 "Complex interdisciplinary studies of oceanologic processes which determine functioning and evolution of ecosystems in the coastal zones of the Black Sea and the Sea of Azov" and FNNN-2022-0002 "Monitoring of the carbonate system, CO₂ and its fluxes in the marine environment of the Black and Azov Seas", and with the support of the RFBR project No. 20-35-90103.

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REFERENCES OvsyanyE. I. GurovK. I. Research of Organic Carbon and Carbonate Content in the Bottom Sediments of the Crimean Southern Coast Shelf Physical Oceanography 2016 1 60 70 10.22449/1573-160X-2016-1-60-70 DauvalterV. A. Factors of Formation of Chemical Composition of Lake Sediments Murmansk MGTU 2002 75 (in Russian) GurskyYu. N. Geochemistry of Lithohydrosphere of Inland Seas: Vol. 1. Methods of Study and the Processes of Formation of the Chemical Composition of Interstitial Waters in the Bottom Sediments from the Black, Azov, Caspian, Baltic, White and Barents Seas Moscow PC GEOS 2003 331 (in Russian) RozanovA. G. VolkovI. I. Bottom Sediments of Kandalaksha Bay in the White Sea: The Phenomenon of Mn Geochemistry International 2009 47 10 1004 1020 10.1134/S001670290910005X KuftarkovaE. A. KovriginaN. P. RodionovaN. Yu. Hydrochemical Regime of the Area Adjacent to Omega Bay and Factors That Shape It Ekologicheskaya Bezopasnost' Pribrezhnoy i Shel'fovoy Zon i Kompleksnoe Ispol'zovanie Resursov Shel'fa [Ecological Safety of Coastal and Shelf Zones and Comprehensive Use of Shelf Resources] 1999 175 189 (in Russian) MironovO. G. KirukhinaL. N. AlyomovS. V. Ecological Characteristic of Kazachva Bay (the Black Sea) Ecology of the Sea 2002 61 85 89 (in Russian) ArtamonovYu. V. SkripalevaE. A. FedirkoA. V. ShutovS. A. DerjushkinD. V. ShapovalovR. O. ShapovalovYu. I. ShcherbachenkoS. V. Waters Circulation in the Northern Part of the Black Sea in Summer – Winter of 2018 Ecological Safety of Coastal and Shelf Zones of Sea 2020 1 69 90 10.22449/2413-5577-2020-1-69-90 (in Russian) LavrovaO. Yu. MityaginaM. I. SabininK. D. SerebryanyА. N. Study of Hydrodynamic Processes in the Shelf Zone Based on Satellite Data and Subsatellite Measurements Sovremennye Problemy Distantsionnogo Zondirovaniya Zemli iz Kosmosa 2015 12 5 98 129 (in Russian) Study of the State of the Ecosystem of the Coastal Part of the Black Sea in the Greater Sochi Area Study of the State of the Ecosystem of the Coastal Part of the Black Sea in the Greater Sochi Area Water Industry of Russia: Problems, Technologies, Management 2008 5 6 25 (in Russian) NemirovskayaI. A. LisitzinA. P. Hydrocarbons in Waters and Bottom Sediments of Coastal Areas in the Northeastern Part of the Black Sea Doklady Earth Sciences 2015 464 1 972 978 10.1134/S1028334X15090202 MatishovG. G. StepanyanO. V. KharkovskiyV. M. SoierV. G. Current Data on Water Pollution of the Sea of Azov and Black Sea with Petroleum Hydrocarbons Vestnik SSC RAS 2014 10 4 49 52 (in Russian) GlumovI. F. KochetkovM. V. Technogenic Pollution and the Processes of Natural Self-Purification of the Caucasian Zone of the Black Sea Moscow Nedra 1996 502 (in Russian) KorpakovaI. G. KorotkovaL. I. LarinA. A. KornienkoG. G. Pesticides and Polychlorbiphenyls in the North-Eastern Black Sea Ecosystem by the Data Collected in 1992-2012 Problems of Fisheries 2013 14 4 744 756 (in Russian) TikhonovaE. A. Organic Matter of Bottom Sediments of the Crimean and Caucasian Coasts (Azov and Black Seas) Ecological Safety of Coastal and Shelf Zones of Sea 2021 3 52 67 10.22449/2413-5577-2021-3-52-67 (in Russian) PavlenkoL. F. SkrypnikG. V. AnokhinaN. S. KlimenkoT. L. EvseevaA. I. EkilikV. S. LarinA. A. KorpakovaI. G. Pollution of Russian Coastal Waters of the Black Sea by Petroleum Products and Polycyclic Aromatic Hydrocarbons Problems of Fisheries 2013 14 4 785 795 (in Russian) ChasovnikovV. K. ChzhuV. P. OcherednikO. A. Analysis of Concentrations of Pollutants (Petroleum Products, Phenols, Synthetic Surfactants, Ocps, Pahs, Heavy Metals, etc.) in the Water Column and in the Bottom Sediments of Gelendzhik and Blue Bays ZatsepinA. G. KuklevS. B. Some Results of Multidisciplinary Coastal Expedition "Black Sea – 2017" at R/V "Ashamba" Moscow Scientific World 2018 67 78 10.29006/978-5-91522-472-7-2018.3 (in Russian) EvseevaA. I. KorablinaI. V. GevorkyanZh. V. KatalevskyN. I. GorgolaL. G. Assessment of Water and Bottom Sediment Pollution with Heavy Metals and Arsenic in the Caucasus Region of the Black Sea at the Present Time Aquatic Bioresources & Environment 2020 3 3 7 16 10.47921/2619-1024_2020_3_3_7 (in Russian) KorablinaI. V. BarabashinT. O. KatalevskyN. I. Heavy Metals in the Bottom Sediments of the Black Sea Northwestern Shelf in Recent Years Physical Oceanography 2021 28 5 549 566 10.22449/1573-160X-2021-5-549-566 EremeevV. N. KonovalovS. K. RomanovA. S. The Distribution of Oxygen and Hydrogen Sulfide in Black Sea Waters during Winter-Spring Period Physical Oceanography 1998 9 4 259 272 10.1007/BF02522712 WeissR. F. The Solubility of Nitrogen, Oxygen and Argon in Water and Seawater Deep Sea Research and Oceanographic Abstracts 1970 17 4 721 735 10.1016/0011-7471(70)90037-9 OrekhovaN. A. KonovalovS. K. Polarography of the Bottom Sediments in the Sevastopol Bay Physical Oceanography 2009 19 2 111 123 10.1007/s11110-009-9038-6 LutherG. W. GlazerB. T. MaSh. TrouwborstR. E. MooreT. S. MetzgerE. KraiyaCh. WaiteT. J. DruschelG. Use of Voltammetric Solid-State (Micro)Electrodes for Studying Biogeochemical Processes: Laboratory Measurements to Real Time Measurements with an in Situ Electrochemical Analyzer (ISEA) Marine Chemistry 2008 108 3-4 221 235 10.1016/j.marchem.2007.03.002 TaillefertM. BonoA. B. LutherG. W. Reactivity of Freshly Formed Fe(III) in Synthetic Solutions and (Pore)Waters: Voltammetric Evidence of an Aging Process Environmental Science & Technology 2000 34 11 2169 2177 10.1021/es990120a LjutsarevS. V. The Determination of Organic Carbon in the Sea Bottom Sediments by Means of Dry Oxidation Oceanology 1986 26 4 704 708 (in Russian) ZabegaevI. A. Shul'ginV. F. OrekhovaN. A. Application of Instrumental Methods for Analysis of Bottom Sediments for Ecological Monitoring of Marine Ecosystems Scientific Notes of V.I. Vernadsky Crimean Federal University. Biology. Chemistry 2021 7 73 242 254 (in Russian) KostylevaA. V. Distribution of Dissolved Organic Carbon in River Mouth Areas of the Greater Sochi Region (North-Eastern Part of the Black Sea) Oceanology 2015 55 2 200 206 10.1134/S0001437015020071 MakkaveevP. N. ZavyalovP. O. Runoff of Small and Medium Rivers of the Russian Black Sea Coast and Its Influence on Water Characteristics LisitzinA. P. The Black Sea System Moscow Scientific World 2018 287 322 10.29006/978-5-91522-473-4.2018 (in Russian) OrekhovaN. A. Nutrients Dynamics in the Surface Waters of the Black Sea Physical Oceanography 2021 28 6 660 676 10.22449/1573-160X-2021-6-660-676 OvsyanyiE. I. KonovalovS. K. Kotel'yanetsE. A. Mitropol'skiiA. Y. Organic Carbon and Carbonates in the Recent Bottom Sediments of the Kerch Strait Geochemistry International 2015 53 12 1123 1133 10.1134/S0016702915120071 GurovK. KonovalovS. Bottom Sediments and Their Properties in the Crimea Coastal Regions 20th International Multidisciplinary Scientific GeoConference SGEM 2020 2020 20 3.1 815 822 10.5593/sgem2020/3.1/s15.105 AleskerovaA. A. KubryakovA. A. GoryachkinYu. N. StanichnyS. V. Propagation of Waters from the Kerch Strait in the Black Sea Physical Oceanography 2017 6 47 57 10.22449/1573-160X-2017-6-47-57 KurinnayaYu. S. GurovK. I. ZabegaevI. A. OrekhovaN. A. Redox Conditions and Characteristics of Bottom Sediments in the Bays of the Sevastopol Region Ecological Safety of Coastal and Shelf Zones of Sea 2022 1 42 54 10.22449/2413-5577-2022-1-42-54 RickardD. LutherG. W. Chemistry of Iron Sulfides Chemical Reviews 2007 107 2 514 562 10.1021/cr0503658 OrekhovaN. A. KonovalovS. K. Oxygen and Sulfides in Bottom Sediments of the Coastal Sevastopol Region of Crimea Oceanology 2018 58 5 679 688 10.1134/S0001437018050107 ZatsepinA. G. KremenetskiyV. V. StanichnyS. V. BurdyugovV. M. Black Sea Basin-Scale Circulation and Mesoscale Dynamics under Wind Forcing FrolovA. V. ResnyanskyYu. D. Modern Problems of Ocean and Atmosphere Dynamics: The Pavel S. Lineykin memorial volume Moscow Triada LTD 2010 347 368 (in Russian) BelkinaN. A. Changes in the Redox State of Lake Bottom Sediments under the Influence of Anthropogenic Factors (On the Example of Ladoga and Onega Lakes) Society. Environment. Development 2014 3 32 152 158 (in Russian)