Assessment of tropho-saprobiological status of the Pobedy Park Pond (Kaliningrad) based on hydrochemical and algological indicators

This paper presents the results of a comprehensive assessment of the ecological and hydrochemical status and algal community of a small urban water body – an unnamed pond located in Pobedy Park (Kaliningrad) – conducted from April 2024 to March 2025. Based on the monthly monitoring across three sampling stations, the study identifies the spatio-temporal dynamics of key hydrochemical parameters, including dissolved oxygen, nutrients (ammonium nitrogen, nitrites, phosphates, total iron) and permanganate index. In order to provide a robust biological characterisation, the phytoplankton composition, abundance, and biomass have been analysed using standard hydrobiological protocols. The findings establish that the water body exhibits chronically high ammonium nitrogen levels, exceeding fisheries maximum allowable concentrations throughout the entire annual cycle, alongside critical dissolved oxygen deficit during the spring and summer months. A statistically significant correlation has been identified between precipitation intensity and the level of organic pollution. Furthermore, the total iron concentrations are of mixed origin, resulting from the combined influence of natural groundwater and runoff from urbanised areas. According to hydrochemical indicators, the pond can be classified as eutrophic, β-mesosaprobic. Algological analysis revealed the dominance of green algae, diatoms and cyanobacteria; peak phytoplankton biomass values indicate the ecosystem's eutrophic status. The morphometric characteristics of the pond, coupled with local point sources of pollution, drive pronounced spatial heterogeneity in environmental quality; specifically, the northern sector of the pond serves as a primary accumulation zone for pollutants due to the influx of stormwater runoff.

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