Kazakhstan's capital has stepped up efforts to clean and restore the ecosystem of the Yesil River. According to the Astana city administration, this year the intensity of water blooming in some areas exceeded long-term averages due to abnormal heat and lower water levels, reports infohub.kz.
External factors also affect the river's condition: water quality depends on its state in upstream regions. Additional pressure comes from nutrients—nitrogen and phosphorus compounds—as well as organic pollution. Experts do not rule out unauthorized discharges into the river and its tributaries, the Sarybulak and Akbulak streams. All this contributes to the active growth of blue-green algae.
To combat blooming in stagnant areas with weak flow, a suspension of the green microalgae chlorella is planned. The city administration emphasizes that this method is environmentally safe and an alternative to chemical agents. Chlorella actively absorbs nitrogen and phosphorus compounds that promote the growth of blue-green algae, thereby curbing their development and restoring the natural biological balance of the water body. Through photosynthesis, it enriches the water with oxygen, creating favorable conditions for fish and other aquatic organisms, and supports natural self-purification processes.
Ecologists note that the effect of chlorella will be gradual: restoring biological equilibrium takes time, with first results expected a few weeks after the suspension is applied.
Earlier, photos and videos showing a bright green coating on the water near the Tulpar Bridge appeared on social media, causing concern among residents. The city's Department of Environmental Protection and Natural Resources said that specialists, together with the ecology department, inspected the area and took water samples for laboratory analysis. They explained that some areas experience a seasonal phenomenon—water blooming caused by intensive development of phytoplankton (cyanobacteria) under high air temperatures, low flow velocity, and favorable hydrometeorological conditions.