Lake Baikal 贝加尔湖

Lake Baikal， a lake located in the southern part of eastern Siberia in Russia. It is the oldest existing freshwater lake on Earth， as well as the deepest continental body of water， having a maximum depth of 1，620 meters. Its area is some 31，500 km2， with a length of 636 km and a width of 48 km on average. It is also the worlds largest freshwater lake by volume， containing about one-fifth of the fresh water on Earths surface， some 23.6 trillion m3. Into Lake Baikal flow more than 330 rivers and streams， including the Selenga， Barguzin， Upper Angara， Chikoy， and Uda.

Baikal is surrounded by mountains， some of which rise more than 2，000 meters above the lakes surface. The sedimentary strata on the floor of the lake may be as much as 6，100 meters thick. In 1862， flood caused by a quake inundated about 200 km2 in the northern Selenga delta， creating a new bay in Baikal known as Proval Bay.

The lake hollow is not symmetrical， having steep slopes on the western shores and gentler slopes on the eastern. Baikal contains some 27 islets and islands. The influx of water into the lake is mainly from rivers， chiefly the Selenga. The only outflow is through the Angara River， a tributary of the Yenisey.

Baikals climate is much milder than that of the surrounding areas. Winter air temperatures are on average ?21℃， and August temperatures average 11℃. The lake surface freezes in January and thaws in May or June. The water temperature at the surface in August is between 10℃ and 12℃ and reaches 20℃ in the offshore shallows. Waves can be as high as 4.6 meters. The water is very clear， from the surface one can see to 40 meters. Its salinity is low， and it contains a few minerals.

贝加尔湖位于俄罗斯东西伯利亚南部，是地球上现存最古老的淡水湖，也是最深的陆地水体，最深处达1620米。贝加尔湖长636千米，平均宽48千米，面积约3.15万平方千米。贝加尔湖也是世界上体积最大的淡水湖，蓄水量约23.6万亿立方米，约占全球地表淡水总量的五分之一。有330多条河川注入贝加尔湖，包括色楞格河、巴尔古津河、上安加拉河、奇科伊河和乌第河。

贝加尔湖被群山环绕，其中一些山高出湖面2000多米。湖底沉积物厚度可能达到6100米。1862年，一场因地震引发的洪水淹没了色楞格河三角洲北部约200平方千米的土地，在贝加尔湖形成了一个新的湖湾——普罗瓦尔湾。

湖中的凹陷构造不对称，西岸坡陡，东岸坡缓。贝加尔湖中大约有27座岛屿。注入湖中的水大部分来自河流，主要为色楞格河。而唯一的外流出口是叶尼塞河的支流安加拉河。

贝加尔湖的气候比周边地区要温和很多。冬季的平均气温为?21℃，8月平均气温为11℃。湖面在1月结冰，5月或6月解冻。8月份湖面水温在10℃—12℃，近岸浅滩达到20℃。浪花可高达4.6米。贝加尔湖湖水清澈，能见度可达40米。湖水盐度较低，含少量矿物质。

Plant and animal life in the lake is rich and various. There are between 1，500 and 1，800 animal species at different depths， and hundreds of plant species live on or near the surface. The majority of the species are unique to Baikal. The one mammal species is the Baikal seal. There are more than 320 bird species in the Baikal area.

Industries along the shores of Baikal include mining （mica and marble）， the manufacture of cellulose and paper， shipbuilding， fisheries， and timber. There are many mineral springs， and lots of visitors come here for the curative properties of the waters. A pulp and paper mill built on Lake Baikals southern shore in 1966 drew strong protests from local scientists because its wastes were polluting the water， and in 1971 the government adopted a law to protect the lake from polluting emissions.

The protection of natural resources in the area began with the establishment of the Barguzinsky Nature Reserve in 1916， subsequently there were added two nature reserves and two wildlife reserves， and two national parks. The Lake Baikal Coastal Protection Zone， covering the lake and its environs （a total of 88，000 km2）， was created in 1987， and the same area was listed as a UNESCO World Heritage Site in 1996.

湖中動植物种类繁多，在不同深度生活着1500到1800种动物，湖面或近湖面水域则生活着数百种植物，大多数物种为贝加尔湖的特有物种。湖中还生活着一种哺乳动物——贝加尔海豹。贝加尔湖地区有320多种鸟类。

贝加尔湖沿岸工业包括采矿业（云母和大理石）、纤维素和纸张制造业、造船业、渔业和木材加工业。该地区的矿泉资源丰富，具有水疗效果，许多游客慕名而来。1966年，贝加尔湖南岸建起了一家纸浆造纸厂，但遭到了当地科学家的强烈抗议，因为工厂的废弃物会污染水体。1971年，政府通过了一项法令，以保护贝加尔湖免受污染排放的侵害。

贝加尔湖地区的自然资源保护始于1916年巴尔古津斯基自然保护区的设立，随后又相继增加了两个自然保护区、两个野生动物保护区，以及两个国家公园。贝加尔湖海岸保护区创建于1987年，包括湖泊及其周边地区（总面积为8.8万平方千米）。1996年，该地区被联合国教科文组织列入世界遗产名录。

Word Bank

volume /'v?lju?m/ n. 体积；容积

How do you measure the volume of a gas？

slope /sl??p/ n. 斜坡；坡地

thaw /θ??/ v. 解冻，融化

Its starting to thaw.

shallows /'??l??z/ n. （河海的）浅水处，浅滩

At dusk more fish come into the shallows.