About Lake Hövsgöl
Lake Hövsgöl (also referred to as Hövsgöl nuur, Lake Khovsgol and Lake Khubsugul) is a large, deep and ancient lake located in the northernmost extension of Mongolia. The lake is 136 km long, 20-40 km wide, 260 m deep, and accounts for nearly 70% of all freshwater in Mongolia. The outlet, Egiin Gol, flows south then east to join the Selenge River, Mongolia’s most extensive river system. The Selenge, in turn, feeds into Lake Baikal, which lies in Russia some 200 km to the east-northeast of Hövsgöl. The latitude is approximately 50°N and the lake's surface lies 1645 m above mean sea level.
Lake Hövsgöl lies in one of the numerous tectonic basins of the Baikal Rift System, a complex of extremely old faults that were reactivated following the collision of the Indian subcontinent with Eurasia. The age of the lake itself has been variously estimated at 5 million, 2.4-4.0 million, and 2 million years old. Even with such a range, it’s among the oldest lakes in the world. Glaciers probably never reached Lake Hövsgöl during the last Ice Age, but mid-Pleistocene terraces located some 120 m below the surface indicate dramatic drops in lake levels at that time.
The lake itself occupies more than half of its 4920 km2 watershed. Much of the remaining is covered by larch-dominated taiga forest underlain with permafrost. Steppe vegetation predominates on the floor and south-facing slopes of stream valleys, while alpine tundra generally occurs above 2300 m in altitude.
The lake is fed by nearly a hundred small tributaries, but only about 20 of them maintain measurable flows for more than one or two months during the year. Many of the streams flow into small bays or into small ponds and wetlands. Except for those originating from springs, all streams freeze completely during the winter.
The harsh mid-continental climate characterized by long, frigid winters and meager precipitation has limited agriculture and human populations. There are two towns on the lake. Historically, they were supported by forestry and trade with Russia, but they have declined following the breakup of the Soviet Union. Semi-nomadic pastoralism has a long history in the region. Traditionally, herds were composed of sheep, yak-cow mixes and horses. However, herds of cashmere goats—prized for their wool, but more destructive in their feeding habits—have increased.
Limited human populations and economic activity has resulted in a remarkably pristine environment. The lake is effectively unpolluted and terrestrial communities are similar to those that existed centuries ago. The landscape supports notable wildlife, including Argali (Ovis ammon), Ibex (Capra siberica), Musk Deer (Moschus moschiferus), Brown Bear (Ursus arctos) and possibly Snow Leopard (Uncia uncial). The entire watershed lies within Hövsgöl National Park, which was created in 1992.
Lake Hövsgöl is an ultra-oligotrophic lake with high levels of dissolved oxygen, high transparency and low levels of both nutrients and organic carbon. Widespread deposits of limestone and dolomite in the southern and southeastern watershed results in relatively high dissolved carbonate levels and extensive marl deposits in lake sediments. The lake freezes over during winter and remains cold during the summer.
Primary production is low and probably phosphorus-limited. Secondary production also low. Fishes within the lake exhibit conspicuously slower growth, delayed maturation and lower fecundity than identical or comparable fishes from the adjacent Selenge drainage.
Lake Baikal, a sister lake of Lake Hövsgöl, is notable for its remarkable biodiversity and extremely high levels of endemism (>70% for many groups). In contrast, Lake Hövsgöl contains more modest biodiversity and endemism (typically 10-20% in studied groups) is substantially lower. On the other hand, endemic taxa account for most of the abundance in the zooplankton and invertebrate benthos. Significantly, most non-endemics are either cosmopolitan or widely-distributed Eurasian taxa rather than those characteristic of the greater Baikal or Yensei drainages.
Modest biodiversity at Hövsgöl can, in part, be attributed to both its ultra-oligotrophic status and its harsh environment. It lies at a much higher elevation (1645 m above mean sea level) that does Lake Baikal (456 m or 1496 ft) and has a shorter growing season. Geologic history, including drastic Pleistocene regressions, may also contribute to the paucity of species.