Sevan shows low levels of algal bloom in 2024–2025

The Armenian Ministry of Environment reports that the process of algal bloom in Lake Sevan has been at a relatively low level this year compared to recent years.

According to the Hydrometeorology and Monitoring Center, which carried out water quality monitoring and sampling on August 27-29, no signs of intensified blooming were observed during fieldwork. Samples were taken from both surface and deep-water layers.

Preliminary results show:

• Water transparency reached 4.8 meters in Big Sevan and 5.6 meters in Small Sevan.

• Dissolved oxygen levels were sufficient for aquatic life in surface and mid-layers (above 6 mg/l), though near the bottom they ranged between 1.1–5.5 mg/l, classified as “moderate to poor”.

• Phosphate levels were rated “excellent to good” at the surface, and “good to moderate” at the bottom.

• Ammonium levels were rated “moderate to insufficient” throughout the lake.

• Nitrate levels were rated “excellent to good” across all depths.

Laboratory testing of August samples is still ongoing and full results will be released later. As of September 1, no bloom intensification was recorded at monitoring sites in Sevan Peninsula, Shorzha, Karchaghbyur and Martuni.