Lake Baikal

• 1. Introduction

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  Lake Baikal holds roughly 22 to 23 percent of all the fresh surface water on Earth. That single fact stops most people in their tracks, because the lake sits quietly in southern Siberia, known mainly as a cold, remote body of water that freezes over for winter. Yet Baikal contains more freshwater than all of the North American Great Lakes combined. It is the deepest lake in the world, reaching 1,642 meters at its lowest point. Its floor lies 1,186.5 meters below sea level, and beneath that floor stretches another 7 kilometers of accumulated sediment. How did a crack in the Siberian earth become the planet's most extraordinary reservoir of fresh water? And what has lived inside it, undisturbed, for tens of millions of years? Those questions run through everything that follows.

• 2. A Crack in the Earth

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  Baikal is not a lake that was carved by glaciers or left behind by a retreating sea. It formed as the Earth's crust pulled slowly apart along the Baikal Rift Zone, and that process has never stopped. The rift widens by about 4 millimeters per year. The fault zone remains seismically active, and hot springs bubble up along its edges. The rift floor sits somewhere between 8 and 11 kilometers below the lake surface, making it the deepest continental rift on Earth.

  The lake is 636 kilometers long and 79 kilometers wide, divided into three distinct basins. The North basin reaches roughly 900 meters deep, the Central basin drops to about 1,600 meters, and the South basin reaches around 1,400 meters. Academician Ridge separates the North and Central basins, while the Selenga Delta and the Buguldeika Saddle mark the boundary between the Central and South. Up to 330 rivers feed the lake, among them the Selenga, the Barguzin, and the Upper Angara. A single outlet drains it: the Angara River, which eventually joins the Yenisey.

  Because Baikal sits at high latitude but was never scraped by continental ice sheets, its sediments have accumulated undisturbed for an extraordinary span of time. Cooperative deep-drilling studies carried out by Russian, American, and Japanese scientists in the 1990s extracted cores that carry a detailed climatic record reaching back 6.7 million years.

• 3. Ancient and Alive

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  At between 25 and 30 million years old, Baikal is the most ancient lake in geological history. That age matters because it allowed evolution to run experiments that younger lakes simply have not had time to attempt. More than 1,000 species of plants and 2,500 species of animals are currently documented in the lake, and researchers believe both counts are significantly underestimates.

  The Baikal seal, known locally as the nerpa, is the only freshwater seal in the world and is found nowhere else on Earth. Its primary food source is another creature unique to the lake: the golomyanka, a long-finned, translucent fish that lives in the open water at depths of 100 to 500 meters. Two species exist, Comephorus baicalensis and C. dybowskii. Together with deep-water sculpins, they rank as the deepest-living freshwater fish on the planet.

  Among invertebrates, the amphipods are a case study in what happens when a species has millions of years and a stable environment to diversify. More than 350 species and subspecies of amphipods are endemic to the lake. Some species of the genus Acanthogammarus reach a body length of 7 centimeters, a size that has been compared to the gigantism seen in Antarctic amphipods and is linked to the lake's exceptionally high dissolved oxygen levels. A single copepod species, Epischurella baikalensis, accounts for 80 to 90 percent of the total biomass in the water column; it is estimated that this one species filters the entire volume of the lake every 23 years.

  The sponges that line the lake floor are also unique. About 15 species belong to the endemic family Lubomirskiidae, which colonized the lake roughly 3.4 million years ago. Three species, including Lubomirskia baicalensis, can reach a meter or more in length, which is unusually large for freshwater sponges. In areas where they are common, L. baicalensis forms branching structures that create underwater forests. Most of the lake's sponges appear green when alive because of symbiotic algae living inside them.

• 4. The Water Itself

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  Baikal is ranked among the clearest lakes in the world. During winter, water transparency in open sections can reach considerable depths, though it narrows during summer. Unlike Lake Tanganyika or the Black Sea, Baikal is rich in oxygen all the way to its deepest points, which is one reason life penetrates to the very bottom.

  The lake surface sits 455.5 meters above sea level and freezes from early January through early May or June, with ice reaching an average thickness of 0.5 to 1.4 meters in most areas and exceeding 2 meters where hummocks form. When the ice breaks up in late spring, the upper 300 meters or so become homothermic at around 4 degrees Celsius as the water mixes. By August, surface temperatures in the main sections can reach about 16 degrees Celsius, while the depths below 300 meters hold to a nearly constant temperature year-round.

  The average surface temperature has climbed by almost 1.5 degrees Celsius over the past 50 years, shortening the ice season. Hydrothermal vents have been found in various locations, some releasing water at around 50 degrees Celsius. Their local warmth makes little difference to the lake's overall temperature given its vast volume.

• 5. Human Arrivals

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  Near the village of Mal'ta, about 160 kilometers northwest of the lake, remains of a young male known as "MA-1" or "Mal'ta Boy" are evidence of human habitation in the area roughly 24,000 years before the present. An early recorded tribe in the area was the Kurykans, who gave the lake a name translating to "much water" in the sixth century. Later, the Buryats called it "natural lake" (Baygal nuur), and the Yakuts called it "rich lake" (Bay gol).

  The lake sat within the former northern territory of the Xiongnu confederation and became one site of the Han-Xiongnu War, as armies of the Han dynasty pursued Xiongnu forces from the second century BC to the first century AD. Han chroniclers recorded the lake as a "huge sea" and designated it the North Sea, Beihei, of their semimythical Four Seas. Lake Baikal then fell under the Anbei Protectorate of the Tang dynasty from 647 to 682 CE.

  Russian expansion into the Buryat territory around the lake between 1628 and 1658 came as part of the broader Russian conquest of Siberia. In 1643, Kurbat Ivanov traveled up the Lena River and became the first European to see Lake Baikal and Olkhon Island. By 1652, Vasily Kolesnikov had reported routes from the Barguzin outpost toward what would become Chita and Nerchinsk. Russians of the era often called the lake the "Baikal Sea" rather than merely a lake; that usage appears in the Life of Protopope Avvakum, written by a man who lived from 1621 to 1682, and on late-17th-century maps by Semyon Remezov. A folk song still circulating today opens with the words "Glorious sea, sacred Baikal."

• 6. Rails, Ice, and War

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  The Trans-Siberian Railway was built between 1896 and 1902. Constructing the section that curved around the southwestern end of Lake Baikal required 200 bridges and 33 tunnels. Until that difficult stretch was finished, a train ferry named the SS Baikal carried railcars across the lake between Port Baikal and Mysovaya. During the same construction period, a major hydrogeographical expedition led by F.K. Drizhenko produced the first detailed contour map of the lake bed.

  The lake became the setting for conflict twice in the early 20th century. In 1918, a minor military engagement between the Czechoslovak Legion and the Red Army took place on its waters. Then in the winter of 1920, the retreating White Russian Army crossed the frozen lake during what became known as the Great Siberian Ice March. The wind on the open ice was so severe that many soldiers and civilians froze in place where they fell, their bodies remaining until the spring thaw.

  Decades later, in 1956, the completion of the Irkutsk Dam on the Angara River raised the overall level of Lake Baikal by 1.4 meters. In July 2008, Russia sent two small submersibles, Mir-1 and Mir-2, to descend toward the lake bottom for geological and biological tests. They reached 1,580 meters, falling short of the existing freshwater diving record of 1,637 meters set by Anatoly Sagalevich in 1990, also in Lake Baikal aboard a Pisces submersible. Russian scientist and federal politician Artur Chilingarov led the 2008 mission alongside Russian president Vladimir Putin.

• 7. Industrial Pressure

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  The Baykalsk Pulp and Paper Mill was built directly on the shoreline in 1966. The plant bleached paper using chlorine and discharged waste straight into the lake. Soviet scientists objected at the time, arguing that the lake's ultra-pure water should have been reserved for high-quality production such as viscose for the aeronautics and space industries. The industrial lobby overruled them. After decades of protest, the mill closed in November 2008 due to unprofitability. On the 4th of January 2010, production resumed. On the 13th of January 2010, Russian Prime Minister Vladimir Putin introduced legislation legalizing its operation again, citing his personal inspection of the lake from a miniature submarine as evidence that the water was in good condition. In September 2013, the mill underwent a final bankruptcy, with its last 800 workers scheduled to lose their jobs by the 28th of December 2013. Its reservoirs of lignin sludge remain an environmental hazard.

  A separate threat came from Transneft, the Russian oil pipelines state company, which had planned to route a trunk pipeline within 800 meters of the lake shore in a seismically active zone. Environmental activists, Greenpeace, and local citizens opposed the plan. After President Putin ordered the company to consider an alternative route 40 kilometers to the north, Transneft agreed to redirect the pipeline away from any federal or republic natural reserves.

  Since 2010, more than 15,000 metric tons of toxic waste have entered the lake. Local ships dispose of up to 25,000 tons of liquid waste into the lake every year according to reporting by The Moscow Times and Vice. The omul, the endemic whitefish that has long been the lake's most commercially important fish species, is declining. Endemic sponge species are dying across the lake floor, and a rapid growth of putrid algae has been documented.

• 8. Culture and Future

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  Two folk songs tied to Lake Baikal circulate across Russia and neighboring countries including Japan. "Glorious Sea, Sacred Baikal" tells the story of a katorga fugitive and has lyrics documented and edited by Dmitriy P. Davydov, who lived from 1811 to 1888. "The Wanderer" follows a convict trying to return home from Transbaikalia; its lyrics were collected and edited by Ivan Kondratyev and the song served as a secondary theme for Ballad of Siberia, the Soviet Union's second color film, released in 1947.

  UNESCO declared Baikal a World Heritage Site in 1996. In 2007, the Russian government designated the Baikal region a special economic zone, drawing investment in hotels and tourism infrastructure. In 2013, the Russian Federal State Statistics Service recorded 79,179 foreign visitors to Irkutsk and Lake Baikal; by 2014 that count had risen to 146,937. The influx included a noticeable rise in visitors from China and Europe.

  In 2019, a Chinese-owned company called AquaSib began building a bottling plant and pipeline in the town of Kultuk with a stated goal of exporting 190 million liters of water annually to China. Local protests followed, and the regional government halted construction pending analysis. Meanwhile, since 1993, the Baikal Deep Underwater Neutrino Telescope has operated 3.6 kilometers from shore at a depth of 1.1 kilometers, with 192 optical modules searching for cosmic neutrinos in one of the few places on Earth deep enough to make such a search possible.