HYDROCHEMICAL CHARACTERISTICS OF THE EUROPEAN ARCTIC WATERS IN THE SUMMER OF 2021

The article presents the results of studies of the hydrochemical structure of waters in the European Arctic around Svalbard. The data used in the work were obtained from the 84th voyage of the R/V Akademik Mstislav Keldysh in July–August 2021. A total of five transects were considered west, north, and east of Svalbard (Spitsbergen). Concentrations of dissolved oxygen, silicon, phosphate phosphorus, nitrite nitrogen, nitrate nitrogen and ammonium nitrogen were determined. Marked differences in dissolved oxygen distribution were identified between waters of Atlantic and Arctic origin. Surface, intermediate and deep layers were selected throughout the entire water column. Concentrations of silicon, mineral phosphorus and nitrate nitrogen gradually increase with depth. Maximum concentrations of nitrite and ammonium nitrogen are observed in the intermediate layer. It is noted that despite significant differences in the depth of the transects, the main changes occur in the surface and intermediate layers. Nutrient depletion in surface waters was reported in August for the second consecutive year.

1. Juranek L. W. Changing biogeochemistry of the Arctic Ocean: Surface nutrient and CO2 cycling in a warming, melting north. Oceanography, 2022, vol. 35, no. 3—4, pp. 144—155. DOI: 10.5670/oceanog.2022.120.

2. Ardyna M., Arrigo K. R. Phytoplankton dynamics in a changing Arctic Ocean. Nature Climate Change, 2020, vol. 10, pp. 892—903. DOI: 10.1038/s41558-020-0905-y.

3. Arrigo K. R., van Dijken G. L. Continued increases in Arctic Ocean primary production. Progress in Oceanography, 2015, vol. 136, pp. 60—70. DOI: 10.1016/j.pocean.2015.05.002.

4. Henley S. F., Porter M., Hobbs L. et al. Nitrate supply and uptake in the Atlantic Arctic Sea ice zone: seasonal cycle, mechanisms and drivers. Philosophical Transactions of the Royal Society A, 2020, vol. 378, p. 20190361. DOI: 10.1098/rsta.2019.0361.

5. Vancoppenolle M., Bopp L., Madec G. et al. Future Arctic Ocean primary productivity from CMIP5 simulations: Uncertain outcome, but consistent mechanisms. Global Biogeochemical Cycles, 2013, vol. 27, iss. 3, pp. 605—619. DOI: 10.1002/gbc.20055.

6. Ko E., Gorbunov M. Y., Jung J. et al. Effects of nitrogen limitation on phytoplankton physiology in the western Arctic Ocean in summer. Geophysical Research: Oceans, 2020, vol. 125, p. e2020JC016501. DOI: 10.1029/2020jc016501.

7. Mills M. M., Brown Z. W., Laney S. R. et al. Nitrogen limitation of the summer phytoplankton and heterotrophic prokaryote communities in the Chukchi Sea. Frontiers in Marine Science, 2018, vol. 5, art. 362.  DOI: 10.3389/fmars.2018.00362.

8. Krisch S., Browning T. J., Graeve M. et al. The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait North Greenland Sea. Scientific Reports, 2020, vol. 10, p. 15230. DOI: 10.1038/s41598-020-72100-9.

9. Duarte P., Meyer A., Moreau S. Nutrients in water masses in the Atlantic sector of the Arctic Ocean: Temporal trends, mixing and links with primary production. J. of Geophysical Research: Oceans, 2021, vol. 126, iss. 8, p. e2021JC017413. DOI: 10.1029/2021JC017413.

10. Zhuang Y., Jin H., Cai W.-J. et al. Freshening leads to a three-decade trend of declining nutrients in the western Arctic Ocean. Environmental Research Letters, 2021, vol. 16, p. 054047. DOI: 10.1088/1748-9326/abf58b.

11. Walczowski W., Piechura J., Goszczko I. et al. Changes in Atlantic water properties: an important factor in the European Arctic marine climate. ICES J. of Marine Science, 2012, vol. 69, pp. 864—869. DOI: 10.1093/icesjms/fss068.

12. Makkaveev P. N., Polukhin A. A., Nalbandov Yu. R. et al. Dynamics of nutrients in the Yenisei Gulf during the open water period. Arctic: Ecology and Economy, 2019, no. 4 (36), pp. 69—82. DOI: 10.25283/2223-4594-2019-4-69-82. (In Russian).

13. Makkaveev P. N., Polukhin A. A., Khlebopashev P. V. Surface runoff of biogenic elements from the coast of Blagopoluchiya Bay (Novaya Zemlya archipelago). Oceanology, 2013, vol. 53, no. 5, pp. 610—617. DOI: 10.7868/S0030157413050110.

14. Makkaveev P. N., Stunzhas P. A., Melnikova Z. G. et al. Hydrochemical characteristics of the waters of the western part of the Kara Sea. Oceanology, 2010, vol. 50, no. 5, pp. 730—739. (In Russian).

15. Pogojeva M. P., Yakushev E. V., Petrov I. N. et al. Experimental study of the permafrost thawing effect on the content of nutrients and heavy metals in seawater during abrasion destruction of the Arctic coast. Arctic: Ecology and Economy, 2021, vol. 11, no. 1, pp. 67—75. DOI: 10.25283/2223-4594-2021-1-67-75. (In Russian).

16. Guidelines for the chemical analysis of marine and fresh waters in the course of ecological monitoring of fishery reservoirs and areas of the World Ocean that are promising for fishing. Moscow, Izd-vo VNIRO, 2003, 202 p. (In Russian).

17. Modern methods of hydrochemical research of the ocean. Moscow, IO of RAS, 1992, 200 p. (In Russian).

18. Netsvetaeva O. P. Dissolved oxygen in the waters of the European Arctic in summer 2021. Proceedings of the XI International Scientific and Practical Conference “Marine Research and Education (MARESEDU-2022)”. Vol. II (IV). Tver, OOO “PoliPRESS”, 2022, pp. 50—54. (In Russian).

19. Alekin O. A., Lyakhin Yu. I. Ocean chemistry. Leningrad, Gidrometeoizdat, 1984, 344 p. (In Russian).

20. Kudryavtseva E. A., Rusanov I. I., Kravchishina M. D. et al. Primary production characteristics of ecosystems of the European Arctic in August 2020. Geology of the seas and oceans: Proceedings of the XXIV International Scientific Conference (School) on Marine Geology. Vol. III. Moscow, IO of RAS, 2022, pp. 205—209. (In Russian).

21. Vedernikov V. I., Gagarin V. I. Primary production and chlorophyll in the Barents Sea in September–October 1997. Oceanology, 1998, vol. 38, no. 5, pp. 693—703. (In Russian).