Scholarly record
COASTAL HYPOXIA IN AREAS UNDER ANTHROPOGENIC PRESSURE
Abstract
An increase of anthropogenic load and intake of organic matter and nutrients leads to extremely negative consequences for coastal marine ecosystems. This is due to the fact that organic matter, deposited in the bottom sediments, contributes to the consumption of oxygen for its oxidation. With a lack of oxygen on the processes of mineralization of organic matter, its accumulation occurs. Oxygen consumption and organic matter accumulation in bottom sediments lead to appearance of anaerobic conditions in sediments and bottom waters. Oxygen deficiency (hypoxia) zones are formed, that defines ecological characteristics and biodiversity of marine ecosystems. Coastal areas of the Crimean shelf and bays of the Sevastopol region (Balaklava, Kruglaya, Kazach?ya and Sevastopol Bays), which have high recreational, social and economic importance, are considered in this work. The data obtained in September 2018 and July 2019 was analyzed. Samples were taken with plexiglass tubes hermetically sealed above and below. To obtain key redox species profiles of pore water, a voltammetry analysis with a glass Au-Hg microelectrode was used. The oxygen fluxes were calculated at bottom water-sediment boundary. Based on the obtained data, the main biogeochemical processes in the bottom waters and sediments of considered areas were studied; a forecast of oxygen deficiency and anaerobic conditions appearance in the bottom waters was given. In the bays of the Sevastopol region, oxygen deficiency is affected by anthropogenic activity, as well as restricted water dynamics. In the open coastal regions of the Black Sea, with the exception of areas suffer from severe anthropogenic pressure (Yalta, Feodosia Gulf, Karkinitsky Gulf), water dynamics contribute to the saturation of the bottom waters with oxygen The value of oxygen flux and it in bottom water?s concentration were used to calculate the time of development of oxygen deficiency. It was stated periods changed from 5 years in open areas, up to 1 month in regions with restricted water exchange. It was found, that hypoxia is observed at the surface of bottom sediments of the Western part of the Crimean coast, Feodosia Gulf and the coastal part of Crimea in the Sea of Azov. In areas with aerobic conditions, the main factor determined redox conditions is water dynamics. It effects on the oxygen saturation of the bottom waters. However, in case of changing conditions and limiting water exchange in these areas, oxygen deficiency zones may also appear.
Publication Impact Profile
- Citations
- CrossRef - Citation Indexes: 2
- Scopus - Citation Indexes: 3
- Captures
- Mendeley - Readers: 6
Publication details
References14
Zhang J., Gilbert D., Gooday A.J. et al. Natural and human-induced hypoxia and consequences for coastal areas: synthesis and future development, Biogeosciences, no. 7, pp. 1443–1467, 2010.
Borges A.V., Schiettecatte L.S., Abril G., Delille B., Gazeau F. Carbon dioxide in European coastal waters Estuarine, Coastal and Shelf Sci, vol. 70, 375 – 87, 2006.
Orekhova N.A., Konovalov S.K. Oxygen and Sulfides in Bottom Sediments of the Coastal Sevastopol Region of Crimea, Physical Oceanography, vol. 19/no. 2, pp. 111-123, 2009. DOI: 10.1134/S0001437018050107.
Mironova N.V., Pankeeva T.V. Spatial distribution of macrophyte reserves in Kruglaya Bay (Black Sea), Ecosystems, vol. 19, pp. 16-26, 2019. (In Russian)
Orekhova N.A. Ovsyany E.I., Gurov K.I., Popov M.A. Organic matter and grain-size distribution of the modern bottom sediments in the Balaklava Bay (the Black Sea), Physical Oceanography, [e-journal], vol. 25, issue 6, pp.479–488, 2018. DOI: 10.22449/1573-160X-2018-6-479-488.
Kotelyanets E.A., Gurov K.I., Tikhonova E.A., Kondratev S.I. Pollutants in Bottom Sediments in the Balaklava Bay (the Black Sea), Physical Oceanography, [e-journal], vol. 26, issue 5, pp. 414-424, 2019. DOI: 10.22449/1573-160X-2019-5-414-424.
Orekhova N.A., Medvedev E.V., Konovalov S.K. Characteristics of the Sevastopol bay waters’ carbonate system in 2009 – 2015, Physical Oceanography no. 3 (189), pp. 40-51, 2016. (In Russian)
Ovsyanyi E.I., Orekhova N.A. Accumulation of organic carbon in bottom sediments of the Kazach'ya Bay (the Black Sea) resulting from anthropogenic load, Meteorology and Hydrology, no. 5, pp. 85-93, 2019. (In Russian)
Brendel P.J. Luther, III G.W. Development of a Gold Amalgam voltammetric microelectrode for determination of dissolved Fe, Mn, O2, and S (-II) in porewaters of marine and freshwaters sediments, Envir. Sci. Technol., vol. 29, pp. 751 – 761, 1995.
Luther, III G.W. Brendel P.J., Lewis B.L. Simultaneous measurement of O2, Mn, Fe, I-, and S (-II) in marine pore waters with a Solid-State voltammetric microelectrode, Limnol. Oceanogr., vol. 43, issue. 2, pp. 325 – 333, 1998.
Orekhova N.A., Konovalov S.K. Polarography of bottom sediments of the Sevastopol Bay, Marine hydrophysical journal, no2, pp. 52-66, 2009. (In Russian)
Ivanov V.A., Sovga E.E., Khmara T.V., Zima V.V. Thermochaline regime of the Karkinite bay and environmental consequences of nature management, Environmental safety of coastal and shelf zones of the sea, no. 3, pp. 22-33, 2018. (In Russian)
Hyacinthe C., Anschutz P., Carbonel P., Jouanneau J.-M., Jorissen F.J. Early diagenetic processes in the muddle sediments of the Bay of Biscay, Marine Geology, no. 177, pp. 111 – 128, 2001.
Ullman W.J., Aller R.C. Diffusion coefficients in nearshore marine sediments, Limnol. Ocenogr., vol. 27, issue 3, pp. 552 – 556, 1982.
Citing literature
Number of times cited according to Crossref: 2
View or Download full articleAccess options
SWS access login
Login as SWS Scientific CommitteeLogin as SWS Scientific PartnerLogin as SWS AuthorAuthors and approved SWS contributors will read and export their own linked papers after identity matching by SWS profile, email and SGEM GlobalID.
For librarian assistance: [email protected]
Purchase Instant Access
- Article can be downloaded after successful payment.
- Article may be used according to SWS library access terms.
- Article cannot be redistributed.