A review of anthropogenic stressors on Lake Sevan, Armenia

Abstract

The resilience of natural systems may be severely compromised by anthropogenic influences. In this paper, the principal anthropogenic influences on the ecosystem of the Armenian highland lake Sevan during the past century are identified. The diversity and severity of the pressures were influenced by national priorities and the catchment's growth. Changes in the lake's morphometry and the littoral's morphology, as well as unsustainable usage of the lake's fish resources, were among the repercussions. They are discussed depending on how each sort of disturbance affects the ecosystem. Although the timing and degree of each stressor were specified, identifying the direct effects of each stressor was often challenging. The current management decisions and future threats to the lake's ecosystem are discussed. This article describes the history of the anthropogenic change of Lake Sevan and, using it as an example, assesses the ecological footprint of people on natural resources and their repercussions.

Lake-wide assessment of trace elements in surface sediments and water of Lake Sevan

“…1). The water volume of the lake is about 37.9 km 3 , the surface area -1276.4 km 2 (HMCMERA, 2022) and the maximum and mean depths -81 m (Shikhani et al, 2022) and 29.8 m (Gabrielyan et al, 2022), respectively. For further details on Lake Sevan see Wilkinson (2020) and Gabrielyan et al (2022).…”

“…From the economical point of view, the lake pro-vides a very important source of freshwater and freshwater fish in the South Caucasus region. For Armenia, the lake is a natural and cultural treasure, a major strategic resource for drinking water, an irrigation water and hydropower source, a recreation and tourism zone, and a habitat for rich and endemic biological species (Gevorgyan et al, 2020;Gabrielyan et al, 2022). Having such economic and strategic importance, Lake Sevan has been affected by various anthropogenic factors.…”

“…However, the used methodology of these two studies is comparable only to a limited extent with modern approaches. Therefore, and because of the changes that have taken place in the last almost 25 years (Gabrielyan et al, 2022), an update was needed. Relevant changes were e.g., the elevation of the water level of Lake Sevan and the substantial extension of the Sotk gold mine as visible from Google Earth since 2000.…”

Tradescantia-Based Test Systems Can Be Used for the Evaluation of the Toxic Potential of Harmful Algal Blooms

“…The lake comprises two morphologically different parts: a northern deep part (with an average/maximum depth of 35.82/83.62 m), the Small Sevan (SS), and a southern shallow part (with an average/maximum depth of 22.62/43.62 m), the Big Sevan (BS) (data on the location and depth are for 2022, provided by the Institute of Geology of Armenia). Anthropogenic activity, such as lowering the water level, habitat degradation, land use in the catchment area, and overfishing, has severely affected the lake's ecosystem [13]. In particular, land use changes were followed by an increased nutrient supply from the catchment area, especially from the rivers.…”

“…In the 1980s, 57% of nitrogen and 45% of phosphorus entered the lake from the river flow, while only 16% of nitrogen and 27% of phosphorus entered from the diffuse sources [14]. An intensive input of nutrients from the catchment area resulted in an increase in the total average annual algal biomass: from 0.2-0.5 g m −3 (1937-1962) to 2.0-3.0 g m −3 (1976-1983) [13,14]. The first cyanobloom in the lake (Anabaena flos-aquae and Aphanizomenon flos-aquae) occurred in 1964 [15].…”