Nº 4 (2024)

The paper studies the variability of the temperature field at the sea surface on different time scales using hydrological measurements made off the coast of Crimea during 2022–2023 cruises of R/V Professor Vodyanitsky and Copernicus satellite data. It is shown that the intra-annual temperature amplitude according to in situ measurements in 2022 was 18.2 °C, whereas in 2023, it was 16.6 °C. The maximum ranges of spatial temperature changes at the polygon (up to 4–5 °C) were observed during periods of intense heating and cooling of surface waters in April–May and December 2022 and October 2023. On the synoptic scale, the periods of temperature increases (decreases) corresponded to those of local wind decreases (increases) with a delay in the temperature response to changes in the wind speed by 10–12 hours. Satellite data showed differences in the temperature intra-annual cycle and the level of its synoptic variability in 2022 and 2023 from climate norms. In 2022, the minimum and maximum temperatures in the intra-annual cycle were observed two weeks later than according to climate data. In 2023, the time of occurrence of the minimum corresponded to the climate one, and the maximum was observed two weeks earlier than it had been expected from the climate data. The main maximum in the level of synoptic temperature variability was observed in November 2022 and in December 2023, but not in May as it had been expected from the climate data. It is shown that from 2022 to 2023 predominantly positive average monthly temperature anomalies against the climate norms were observed. This reflects the upward tendency in temperature over the past two years.

The article presents the results of coastal litter monitoring on the beaches of the Black Sea from 2016 to 2021. The study was conducted on five beaches of the northeastern Black Sea coast, including urban and suburban areas. The Marine Strategy Framework Directive (MSFD) methodology of the European Commission was used for the collection and classification of litter items. During 13 monitoring sessions, a total of 2633 litter items (108 types, 8 categories) were identified, with plastic being the predominant component, averaging 71.7 % of the total litter volume. The second predominant category was metal, averaging 8.2 % of the found litter. The litter density varied from 47.66 pcs./100 m to 1163 pcs./100 m. The litter density median was 118.26 pcs./100 m on all studied beaches. The inter-annual variability in the litter amount on the beaches shows a decreasing trend in all monitored areas with pronounced peaks in the summer and winter seasons. The main source of the coastal litter pollution was recreational activities, the impact of which was aggravated by lack of developed waste management infrastructure as well as by the proximity of transport routes. The obtained data highlight the necessity of continued monitoring and implementation of measures to reduce pollution, such as improving waste management systems and reducing plastic production and usage. These data can also contribute to legislative and practical initiatives for the protection of the Black Sea marine ecosystems as developed both by the government and people at large.

In recent decades, the interest in polychaetes of the Dorvilleidae family, adapted to exist in marginal biotopes (cold methane seeps, hydrothermal vents, sulphide sediments) has increased. The work aims to analyze the ecological characteristics, distribution and quantitative representation of Dorvilleidae in the Black Sea. The study materials were samples of macrozoobenthos on the Black Sea shelf in 2010–2019, taken with a Okean-50 bottom grab (S = 0.25 m²), and benthos samples, taken in the coastal areas of Crimea in 1997–2023 with a diving bottom grab (S = 0.04 m²). Three species of the family Dorvilleidae were recorded in the northern Black Sea: Dorvillea rubrovittata (Grube, 1855), Schistomeringos rudolphii (Delle Chiaje, 1828), Protodorvillea kefersteini (McIntosh, 1869). Their bathymetric range was limited to the photic zone (up to 50 m). D. rubrovittata occurred mainly in the biotope of hard substrates fouling and formed relatively large aggregations (up to 438 ind.·m⁻²) in underwater channels and caves. The species was first found by us in the northwestern part of the Black Sea. S. rudolphii was recorded in small quantities (2–300 ind.·m⁻²) along the entire Crimean coast. This species was found mainly on shell substrates and among macrophytes. P. kefersteini was recorded in almost the entire northern part of the Black Sea (excluding the Caucasian coasts) on sandy-shell substrates with varying degrees of siltation. It is a mass species, and its density reached significant values in some areas. In Kruglaya Bay (Sevastopol area), a stable population of this species with the highest occurrence (up to 88 %) and density (up to 13,215 ind.·m⁻²) was recorded for a long time. The supposed reason for this is the formation in Kruglaya Bay of large assemblages of bacteria and microalgae, which are a forage base for P. kefersteini.

The article presents the results of experiments on the ability of the green alga Ulva lactuca to absorb and transform diesel fuel from marine water for 5 and 10 days. The original marine water contained 0.62 mg/L of petroleum hydrocarbons, which is about 12 maximum permissible concentrations (MPC). During the experiment with the addition of 20 mg/L of diesel fuel (400 MPC) to the water, the absorption of the introduced hydrocarbons was observed in the experimental tanks without algae. Apparently, they were absorbed by water microorganisms. On the 5th day of the experiment, the petroleum hydrocarbons concentration in the water decreased by 40 % and amounted to 12 mg/L (240 MPC). When ulva thalli were added to the water, the total content of petroleum hydrocarbons in the water on the 5th day decreased by 86 % (to 2.8 mg/L), and on the 10th day, it increased (to 4.2 mg/L). A slight increase in the concentration of diesel fuel hydrocarbons in water indicates a reverse process of releasing hydrocarbons absorbed by ulva into water. In the experiment with the addition of diesel fuel to the water at a concentration of 10 mg/L, the content of hydrocarbons in algae tissues on the 5^th and 10^th days was recorded at the level of 0.6 mg/g. The marker ratio of ∑n-alkanes / ∑ petroleum products in ulva during the experiment was 0.2. A decrease in this indicator to 0.18 on the 10^th day of the experiment indicates the beginning of the transformation of the hydrocarbons chemical structure. When 20 mg/L of diesel fuel (400 MPC) were added to the water, this indicator on the 5^th and 10^th days was 0.25 and 0.28, respectively, indicating an active process of hydrocarbon absorption by the algae surface, which was not yet complete by the 10^th day. The experiment results allow us to conclude that U. lactuca is able to absorb and transform petroleum hydrocarbons and participates in the bioremediation of coastal waters.

The paper considers issues of organization of remote workplaces for automation of in situ measurements of the marine environment. The workplace allows collection of data from a sensor system that measures characteristics of the marine environment in natural conditions; to transfer data to a remote data center via the Internet; to store and backup data. The paper presents algorithms for workplace organization based on modern technologies for data collection and transmission. The implementation of the workplace is detailed on the example of remote control of the weather station Davis Vantage Pro 2. This weather station was installed on the stationary oceanographic platform in Katsiveli to continuously measure parameters of the atmospheric surface layer. The remote control was organized on the basis of the hardware and software platform of a single-board personal computer Raspberry Pi. Two-year tests of the system allow concluding about its reliability and high efficiency. The proposed principles and algorithms can be applied to organization of remote workplaces for performing oceanological measurements in coastal areas with Internet access.