Marine Hydrophysical Institute

Biogeochemistry of the Sea Department

Doctor Sergey K. Konovalov- Head of Biogeochemistry of the Sea Department

Scientists - 11; Engineers - 7.

Basic scientific directions

Interactions between the physical, biological, and chemical processes of the oxic, suboxic and anoxic layers, including redox processes involving nitrogen, sulfur, iron, and manganese cycling, in regard to pathways and regulation of rates, the dynamics of nitrogen fluxes among nutrient and particulate pools and lower trophic levels.
Understanding the roles of new and regenerated production in ecosystem dynamics, sources of new nutrients and their transport mechanisms for the new production, capacity of new production in the Black Sea, f-ratio, and contribution to total production.
Idealized and experimental research of distribution and transport of artificial and natural fracers (physical and chemical) in ocean and use of trace of technologies for controlling dynamics and quality of marine environment.

Results

A serious scientific problem emerged from the discovery of the suboxic zone. The recently suggested hypothesis (Konovalov & Murray, 2001) explained the phenomenon of the suboxic zone by superposition of independent processes at its upper and lower boundary. Generally, eutrophication and global warming should result in broadening and shoaling of the suboxic zone, but the onset of sulfide should remain at a steady state until the level of eutrophication does not prevail the potential of the Bosporus plume. As the influence of the Bosporus plume varies over the sea, the structure of the suboxic zone should also vary reflecting changes in the lateral flux of oxygen and intensity of manganese redox transformations.

Temporal variability in suboxic zone thickness from 1960 to 2001

A theoretical basis for calculating average time of predictability and its dispersion for complex non-linear hydrodynamic models used for forecast of circulation in the Black Sea was developed.
A special method of data filtration allowing to reconstruct scalar oceanographic, hydrobiological and hydrochemical fields was developed.
The developed methods have been applied to reconstruct a climatic field of chlorophyll “a” attractor as well as ¹³⁷Cs, ¹³⁴Cs and ⁹⁰Sr concentration fields in the Black Sea.
Annual ¹³⁷Cs inputs to the Mediterranean Sea from the Black Sea since 1959 till 1998 were obtained.
Concentration of dissolved and suspended ¹³⁷Cs and 90Sr both in bottom sediments and in water of the Dnieper-Bug Estuary and the North-Western Black Sea was estimated. It was shown that relations between ¹³⁷Cs chemical forms were close to those of stable cesium whereas for ⁹⁰Sr they were far from those for equilibrium state.
On the base of ¹³⁷Cs, ¹³⁴Cs and ⁹⁰Sr concentration data observed in 22 cruises of several research vessels in 1986-1995 27 maps were constructed. These maps compose an information block on artificial radioactivity in the Multidisciplinary Digital Atlas on the Azov – Black Sea Basin developed in the Marine Hydrophysical Institute. The maps show spatial and temporal variability of artificial radionuclide concentration in the Black Sea surface waters for a decade passed after the Chernobyl disaster.

For further information please contact:
Biogeochemistry of the Sea Department
Marine Hydrophysical Institute,
2, Kapitanskaya St., Sevastopol, 99011, Ukraine
Phone: 380-692-540452
E-mail: sergey@alpha.mhi.iuf.net

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