From relict crustaceans to elodea: what scientists discovered in Khalzovskoye Lake

      August 27, 2025 12:00

      [172]

      Society

      Nizhny Novgorod ecologists continue a large-scale study of the region’s water bodies. Since the beginning of the year specialists from Lobachevsky State University of Nizhny Novgorod have collected more than 200 water samples from over 15 lakes and ponds in Nizhny Novgorod and the surrounding region. The data obtained will form the basis for scientific papers dedicated to the current state of aquatic ecosystems. This was reported by pravda-nn.ru.

      Similar studies in the region were carried out about 20 years ago and formed the basis of environmental passports for the lakes. Now scientists are updating the information to track changes and evaluate the impact of time and human activity on the aquatic environment. The work is supported by a Russian Science Foundation (RSF) grant and will continue until October.

      Currently research is being carried out on Khalzovskoye Lake in the Sormovsky District. It is reported that the work was timed to coincide with World Lakes Day, which is being observed on August 27, 2025 for the first time in history. This lake, located within the “Koposovskaya Dubrava” natural monument, has rare biodiversity, home to dozens of species of fish, plants and microorganisms. Rare and Red Book-listed species were also found here, including the relict crustacean Ovalona karelica and floating salvinia – a water fern listed in the region’s Red Book.

      During the expedition ecologists measured key water parameters: temperature, acidity (pH), mineralization, chlorophyll level and dissolved oxygen content. All data will be analyzed in the laboratory. Scientists also collected samples of phyto- and zooplankton to study the composition of microscopic communities and assess the lake’s ecological condition.

      According to the researchers, such work allows them to understand how a lake’s ecosystem changes over time. For example, Canadian elodea – an invasive plant that can displace native species and completely overgrow a water body – is now actively spreading in Khalzovskoye Lake.

      Lakes play an important role in maintaining biodiversity, regulating the climate and providing fresh water. There are more than a thousand lakes in the Nizhny Novgorod region, and each of them requires attention and a scientific approach. Scientists emphasize: any lake eventually turns into a swamp — this is a natural process. Already about 15% of Khalzovskoye Lake is overgrown.

      In the coming months ecologists will continue monitoring other water bodies, including Malyshevskoye Lake and the Shuvalovsky Canal. The goal is to track seasonal dynamics and record changes in the ecosystems.

      Earlier it was reported that an inspection began following complaints about the appearance of dead fish and a smell at Kabatskoye Lake in the Bogorodsky District.

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