ПРОГНОЗНА ОЦІНКА ЕКОЛОГІЧНОГО СТАНУ УКРАЇНСЬКОГО СЕКТОРА ЧОРНОГО МОРЯ НА ПІДСТАВІ ЗМІНИ МОРФОФУНКЦІОНАЛЬНИХ ІНДИКАТОРІВ АВТОТРОФНИХ УГРУПОВАНЬ ПІД ВПЛИВОМ КЛІМАТИЧНИХ ФАКТОРІВ І НАСЛІДКІВ ВОЄННИХ ДІЙ (ЧАСТИНА 1. ДІАГНОЗ)

• Datum: 2026
• Hauptverfasser: Мінічева, Г.Г., Тучковенко, Ю.С., Зотов, А.Б., Соколов, Є.В., Мартинюк, М.О., Калашнік, К.С., Маринець, Г.В., Овчарук, В.А.
• Format: Artikel
• Sprache: Ukrainisch
• Veröffentlicht: Marine Ecological Journal 2026
• Schlagworte: автотрофні угруповання; річковий стік; прогностичні зв’язки; екологічний стан; Чорне море; північно-західна частина.
• Online Zugang: https://mej.od.ua/index.php/mej/article/view/723
• Назва журналу: Marine Ecological Journal

In this study, for the first time for the northwestern part of the Black Sea (NWBS), an analysis was conducted of statistically significant relationships between the mean monthly volumes of the spring river runoff of the Danube and the Dnipro (March–June) and the morphofunctional indicators of phytoplankton, macro- and microphytobenthos, as well as the primary production indicator – chlorophyll-a based on long-term datasets from 2000–2024. The main objective of the research is to obtain the coefficients of regression equations that reflect the influence of the annual river runoff of the Danube and the Dnipro on the restructuring of the structural and functional organization of communities of short- and long-cycle forms of aquatic vegetation in the pelagic and benthic zones of the marine ecosystem. These coefficients can subsequently be used to provide a long-term predictive assessment of changes in the ecological state of the sea in regions of freshwater influence, which is planned to be obtained in the second part of this work (Part 2. Forecast). It was established that during the period 2000–2024, there are observable trends toward a general decrease in the volumes of river runoff from the Danube and the Dnipro, both on an annual scale and during the spring period (March–June). An increase in the amplitude of fluctuations in annual runoff volumes was identified for 2000–2024 compared to the previous period, 1981–1999, indicating the influence of the climate changes, manifested in the uneven distribution of precipitation through the year, as well as an increase in the frequency of both intense floods and drought periods. During the period 2000–2020, the long-term average areas of zones with high chlorophyll-a (Chl-a) concentration were approximately 5900 km2 for Chl-a > 2.23 mg·m-3 and 2300 km2 for Chl-a > 4.63 mg·m-3. An increase of 1 km3 in the combined early-spring river runoff of the Danube and the Dnipro is associated with an expansion of moderately eutrophic waters (Chl-a > 2.23 mg·m-3) by 150–200 km2. Analysis of the synchronous effects of monthly river runoff on phytoplankton indicators during the spring period (March– June) revealed similar patterns of relationships for both the Danube and the Dnipro, with the strongest effects observed for surface area indicators (S). The March runoff of both rivers formed strong inverse relationships with S, which is consistent with the dominant influence of winter-type hydrodynamic processes prior to the onset of the intensive flood phase. In April, a strong direct relationship was identified between river runoff and the surface index (SI) of phytoplankton communities, associated with the influence of the peak flood. Analysis of the “delayed” effect of the monthly runoff volumes of the Danube and the Dnipro on phytoplankton indicators in the Odesa region of the NWBS confirmed the presence of a lagged positive (direct) influence in cases where this effect did not manifest within the same month. For the morphofunctional indicators of benthic vegetation – the specific surface area of the macrophyte floristic composition (S/Wx) and the contribution of the epiphytic component (Ce) in the Odesa region of the NWBS scatter plots were obtained and the coefficients of approximation equations were determined. These coefficients reflect the existing statistical relationship between the trends in the mean values of these indicators and the monthly river runoff volumes of the Danube and the Dnipro during the spring months of the long-term period 2000–2024. It has been shown that with an increase in monthly runoff volumes, the values of these indicators also increase. This makes it possible to use the obtained equations to provide predictive assessments of changes in the structural and functional organization of the macro- and microcomponents of benthic vegetation, which are linked to categories of the ecosystem’s environmental status class (ESC). The conducted assessment of the quantitative relationships between the river runoff volumes of the largest rivers in the NWBS and the functional activity and intensity of functioning of autotrophic communities creates a basis for further developing predictive evaluations of possible long-term changes in the ESC categories of the marine ecosystem in the Ukrainian sector of the Black Sea, in accordance with existing scenarios of river runoff changes driven by climate change.