Снігірьов П. М.

Purpose. Study of macrozoobenthos contemporary state in Odessa Bay coastal waters in 2016-2017. Methods. Standard methods of macrozoobenthos sampling, determination, estimation of number and biomass Results. The results of macrozoobenthos biodiversity, structural characteristics and taxonomic composition in Odessa bay coastal waters have been presented. Seasonal dynamics of its number and biomass. has been studied. Assessment of marine environment quality has been performed on the metrics of macrozoobenthos. Conclusions. Altogether 121 taxa of benthic invertebrates were identified in Odessa Bay in 2016-2017. Taxonomic composition and quantitative indicators of macrozoobenthos had clear seasonal variation with maximal devel-opment of benthos in summer period. In spring of 2016, 75 taxa of macrozoobenthos were registered in samples, in summer – 82 taxa, in autumn – 60 taxa, in summer of 2017 – 62 taxa. The basis of macrozoobenthos community was formed be mollusks (Mollusca) with domination of species М. galloprovincialis, as well as representatives of Arthropoda and Annelida. Significant input into macrozoobenthos species composition was made by representatives of the following groups: Bryozoa, Nemertea and Platyhelminthes. Contribution of Porifera, Cnidaria and Phoronida to Odessa Bay benthic communities was insignificant. In 2016-2017 3 alien species were registered in Odessa Bay – bivalves Anadara kagoshimensis and Mya arenaria, as well as gastropod Rapana venosa. Out of 121 macrozoobenthos taxa 4 were listed in the Red Data Book of Ukraine and 6 – in the Black Sea Red Data Book. During the period of studies practically equal quantities of macrozoobenthos taxa were found on different substrates. In samples from loose substrates the number of taxa at different depths varied from 5 to 40 with Shannon diversity index (Н) making 1.7-2.9; on mixed substrate – from 19 to 48 species with Н = 1.3-2.8. Macrozoobenthos number and biomass varied on loose substrates from 0.070х104 to 3.227х104 ind/m2 and from 0.002 to 5.361 kg/m2 and on stony substrate – from 0.667х104 to 170х104 ind/m2 and from 0.088 to 46.811 kg/m2 respectively. Quality of marine environment estimated using AMBI and M-AMBI indices calculated for all the 26 samples was assessed as High in 4 cases, Good in 17 cases and Moderate in 5 cases out of 26. Mean values of the AMBI and M-AMBI indices for different seasons of year were as follows: first decade of June 2016 – 1.84±0.07 and 0.69±0.04 respectively; August 2016 – 1.66±0.12 and 0.84±0.05 respectively; November 2016 – 2.62±0.13 and 0.60±0.02 respectively; June 2017 – 2.72±0.11 and 0.73±0.05 respectively.

Purpose. The results of pilot monitoring project carried out in Odessa Bay coastal waters in 2016-2017 by a research group of the Regional Center for Integrated Monitoring and Environmental Studies (Odessa Na-tional I.I. Mechnikov University) have been summarized. Methods. Primary data on transparency, temperature and salinity of marine water have been collected using standard methods. Data processing, calculation of statis-tics, producing of graphs and maps have been carried out using ArcGIS and Excel software. Results. Temporal and spatial distributions of transparency, temperature and salinity of marine coastal waters of Odessa Bay in the area of Marine Hydrobiological Station of the University for the period from April 2016 to August 2017 have been presented and analyzed. Using the results of analysis of the accumulated experimental data on transparency, temperature and salinity of seawater the peculiarities of those characteristics’ seasonal changes have been revealed. It was demonstrated that marine water transparency was minimal in May and June 2016 (2.2-2.8 m); maximal transparency values for the entire period of observation (7.0 m) was registered in May 2017. A strongly pronounced seasonal variation was revealed in the distribution of marine water temperature in Odessa Bay in 2016-2017, which was determined by spring-summer warming up / autumn-winter cooling down, as well as coastal upwelling, advection of water masses from other marine areas. It was shown that with observations performed every 10 days the desalinated water masses were registered in 13.5% of measurements but never found during monthly surveys at 13 of the micro-polygon. It means that during the detailed monthly surveys in Odessa Bay coastal waters all the cases of advection of desalinated water stayed unregistered. Conclusions. Impact of transformed water masses from the Dnieper-Bug mouth on seasonal cycles of hydrological characteristics in Odessa Bay in 2016-2017 has been established. Violations of the seasonality of thermohaline structure formation in Odessa Bay waters in 2016–2017 due to the longshore cyclonic and compensatory currents impact in the coastal zone have been recorded. Forming of stable two-layer vertical density stratification in Odessa Bay coastal waters at the spring and summer periods of 2016-2017 has been traced.