статья в журнале

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PHYSICAL OCEANOGRAPHY

ISSN:0928-5105
eSSN:1573-160X

2021

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

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 deepsea stations, a cassette of 12 bathometers (the Seabird -Electronics STD-instrument) was applied for taking hydrochemical samples at certain isopycnic surfaces, usually at sigma(t) = 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/m(3). 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 sigma(t) = 14.4 kg/m(3), the content of phosphates and Porg does not exceed 0.1 mu M; 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 sigma(t) = 15.8 kg/m(3), and its maximum - near the isopycnic surface sigma(t) = 16.2 kg/m(3). The minimum content of phosphates varied within 0-1.5 mu M; in 2016-2017 the phosphates concentration maximum did not exceed 8 mu M; in 2018, in many cases, it was higher than 12 mu M, and once, near the Kerch Strait, it exceeded 17 mu M. Increase in the magnitude of the maximum phosphates concentration (in the previous studies in 1988- 2013, it did not exceed 8 mu M) is assumed to be related to installation of the supports for constructing the Kerch Bridge.

Black Sea, hydrogen sulfide formation, nutrient, svertical distribution of phosphates, field data

2021-11-23 13:33:35