Basic regularities of the formation of “new” and regeneration production in the Black Sea

• Published in: Physical oceanography Vol. 16; no. 6; pp. 337 - 349
• Main Author: Krivenko, O V
• Format: Journal Article
• Language: English
• Published: Utrecht Springer Nature B.V 01.11.2006
• Subjects: Brackish; Nitrates; MED, Black Sea
• ISSN: 0928-5105; 0928-5105
• DOI: 10.1007/s11110-006-0037-6

Based on the experimental data obtained in 1990-1993 by the method of isotopic tracers with the help of a stable isotope of nitrogen (^sup 15^N), we establish basic regularities of the formation of "new" and regeneration production in the Black Sea and reveal the factors specifying their combination. It is shown that the rates of nitrate and ammonium uptake by microplankton vary from the minimum values in winter to the maximum values in summer. In the surface layer, the uptake of nitrates corresponding to the amount of "new" production in deep-water layers is equal to 50% (in winter) and 30% (in summer) of the total uptake of inorganic nitrogen compounds by microplankton. In the zone of photosynthesis, the average fractions of nitrates are equal to 31 ± 10% in winter and 41 ± 10% in summer. The minimum values of this parameter are attained in the middle of spring and in autumn. The fraction of "new" production (f-ratio) and the integral content of nitrates in the zone of photosynthesis are connected by a hyperbolic dependence. The period of cyclic transformations of nitrates in this zone decreases from several dozens of days at the beginning of winter to 12 h in the mid-spring. In summer, this period is equal, on the average, to one day. The average period of cyclic transformations of ammonium is equal to 15 ± 4 h in winter and 5 ± 3 h in summer.[PUBLICATION ABSTRACT]