Armenian environment ministry explains why Lake Sevan is 'blooming'
YEREVAN, July 19. /ARKA/. In an explanation issued today, Armenian Ministry of Environment said the algae blooms in the country's largest Lake Sevan is mostly caused by the presence of large amounts of nitrogen and phosphorus in water. These nutrients are washed away from lands and farms that are heavily riddled with nitrogenous and phosphatic fertilizers.
The other factors contributing to the lake's 'blooming' are high water temperature, high light intensity, reduction of hypolimnion layer in the Small Sevan and its disappearance in the Big Sevan due to the drop in the lake's level.
As a result, the concentration of phosphorus in Lake Sevan continues to increase because the lake is overloaded with biological substances brought by sewage as a result of human activities.
At present Lake Sevan is in the stage of intensive blooming. As a result, the concentration of phosphates is decreasing. Compared with July 15, the concentration of phosphate-ions has decreased almost twofold. Absorption of phosphorus by biomass is intensive, and when the concentration of phosphorus in water becomes almost equal to zero, the process of blooming will be completed. According to experts, this process will last for 2-3 weeks.
The content of dissolved oxygen in the bottom layer of Lake Sevan was within 4-8 mg/l. The concentration of dissolved oxygen in the surface and middle layers is sufficient for fauna preservation.
The ministry said it is taking a number of measures to restore Lake Sevan ecosystem, including
regulation of commercial fishing of whitefish, replenishing fish stocks, elaboration of a management plan for the water basin of Lake Sevan, approval of water standards, dismantling of illegal buildings on the shore of the lake, cutting of forest in the territories covered with water and garbage removal.
Lake Sevan is one of the most popular touristic attractions and vacation spots for Armenian citizens, especially during the summer season.
The main source of fresh water in the region, the lake is one of the largest alpine lakes in Europe and Asia located in the heart of the Armenian highlands, at an altitude of 1914 meters.
The length of the lake from north-west to south-east is more than 70 km with water surface area almost 1.5 thousand sq. km. Twenty-eight rivers fall into the lake and one –The River Hrazdan-flows out of it. -0--
