Hydrochemical and microbiological assessment of the current state of the Vostok Bay.

Проведены химико-экологические и микробиологические исследования современного состояния поверхностных прибрежных вод зал. Восток (Японское море). Наиболее напряженная экологическая ситуация отмечена в бухте Гайдамак, в районах у Волчанецкой протоки и устья р. Литовка. Протока, а также приустьевая зона р.Литовка являются главными тревожными участками в морском заказнике Залив Восток . The current state of the Vostok Bay water area (the Sea of Japan) is estimated using hydrochemical and microbiological indicators. The most intense environmental situation was noted for Gaydamak Bight, the area near the Volchanets duct and the mouth of the Litovka River. The duct, as well as the mouth of the Litovka River, are the main alarming sites in the Vostok Bay marine reserve.

CONDITIONS FOR PRIMARY PRODUCTION OF PHYTOPLANKTON IN THE VOSTOK BAY (JAPAN SEA) IN SPRING 2016

The Vostok Bay was surveyed on March 16–18, 2016 with measuring of water properties profiles by oceanographic sondes Sea-Bird SBE-19plus V2 and Rinko Profiler ASTD-102 with sensors of pressure, temperature, conductivity, turbidity, chlorophyll fluorescence, dissolved oxygen, and photosynthetically active radiation (PAR) and collecting of water samples by SBE-32 carousel sampler with 10 liter bottles for further measuring of nutrients (P, Si and N in forms of nitrate and ammonium) and chlorophyll a concentration and phyto- and zooplankton abundance and species composition. Assimilation number (Pb ) of phytoplankton was determined using the optical sensor of dissolved oxygen mounted on logger Rinko AR01-USB and primary production was calculated from the measured values of Pb , Chl a and PAR. Values of primary production ranged from 200 to 2100 mgC/(m2.day). The highest phytoplankton growth was detected at the depth of 8–10 m in the northern Vostok Bay and 10–16 m in its southern part. The total daily production of phytoplankton within the Bay was estimated as 12.5 tC. Species composition of phytoplankton was formed mainly by diatoms (Bacillariophyta) and dinophytes (Dinophyta). The highest biomass of raw phytoplankton was registered at the sea surface, whereas the highest values of chlorophyll concentration occurred mainly at the bottom of the bay. Species composition of zooplankton was typical for spring season, with domination of copepods presented mainly by neritic species; its biomass was in 12 times lower than the phytoplankton biomass, on average. There was concluded that photosynthetic activity of phytoplankton was limited by nitrate availability, therefore it was intensified by penetration of relatively cold, nitrogen-rich waters from the deep-water sea to the Vostok Bay.

USING THE METHOD OF BUILDING OF OPTIMAL HAMILTONIAN CYCLE FOR INVESTIGATION OF SEASONAL CHANGES IN MACROPHYTOBENTOS (ON EXAMPLE OF THE VOSTOK BAY, JAPAN SEA)

Method of building of optimal Hamiltonian cycle is proposed for study of cyclic changes in species composition of macrophytobenthos in the Vostok Bay. Compiled lists of macroalgae and higher plants are composed for each month. Requirements for the species lists comparing are established. The optimal Hamiltonian cycles for the lists without permanent species are different from those for the complete lists because of higher values of the measures of difference, particularly in winter. The Sørensen–Dice coefficient, Jaccard similarity index, or equivalent measures are recommended to use for assessment of the differences between the species lists.