Baikal Ecosystem: from a Disaster to the Rescue

Baikal Ecosystem: from a Disaster to the Rescue

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This figure is well-known: Baikal’s age is about 25 million years. It is very difficult to conceive such a large amount of time. According to various sources, it is one thousand times longer than the period of time the man has lived on the Earth. So even by then Baikal had existed for millions of years! At the same time its global resources are virtually inexhaustible.

Let us take a famous example: if we assume that no rivers any longer run into the Lake which, by the way, remains the only source of fresh water on the planet, the amount of water in Lake Baikal will be enough for approximately 6 thousand years if we take one and a half liters of water per day per person! This fact is rather impressive.

The discussion of the way the ecosystem of the Lake was changing is possible only basing on the researches reconstructing the past of the great Lake. You should as well take into account anthropogenic changes with their peak falling to the last century, alongside with the progress development.

  • In order to understand this issue, let us look at several more indicative figures.
     

Angara takes about 60 cubic kilometers of water out of the Lake per year. The same amount of water flows into the lake through tributaries. At that, half of them (approximately 30 cubic kilometers of water) are brought by Selenga.

Complete substitution of the lake waters by those of its tributaries takes approximately 400 years. During ten years the water from the surface penetrates to a depth of about 300 metres. This means that, in a sense, you can talk about relative sustainability of the ecosystem on a scale of life length of several generations of people.

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The researches of the dated sediments of Lake Baikal showed that the condition of the Lake’s ecosystem had changed significantly 10-15 thousand years ago, after global warming at the end of the Pleistocene. Scientists have already found out that there had been no diatoms in Baikal approximately 18 thousand years ago, when the Earth was experiencing the maximum global glaciation. These are single-celled and colonial algae cells having a “shell” consisting of silicon dioxide. Namely diatoms are one of the most remarkable signs and sensitive indicators of natural waters quality. 

They move and evolve all the time: some species disappear, others appear. Especially active changes occur when water gets overacidified, due to the man’s actions. For example, upon infulx of excess fertilizers from catchment areas: the more active agriculture development is, the faster diatoms differentiate. A thorough analysis of the diatoms from the dated sediments of Lake Baikal has shown that the qualitative composition of diatoms remained absolutely unchanged and that the ratio of different species counts barely changed in Lake Baikal during the industrial revolution, in the period from the beginning to the end of the 20th century, during the time of rapid economic development of Siberia.

  • Why does this happen? Because the man intervenes into the Lake’s ecosystem even more actively.

Lake Baikal is not simply a reservoir of pure water, but a real natural factory with real recycling and conversion of all foreign matters entering the Lake. At the same time recent researches prove: some specific substances in huge amounts enter Baikal all the time. For example, methane which is formed from buried organic matter in the Baikal Lake’s sediments. Solid compounds of methane with water - methane hydrates - are found in significant amounts on the vast areas of the bottom. The supplies of methane at the Lake’s bottom are comparable with the reserves of Kovykta gas field. In some fractures warmed deep water enters hydrate layers, that’s why the hydrates are destroyed, therefore a lot of methane bubble “torches” rush from the bottom to the surface. Sometimes their height reaches several hundred meters. Geophysicists found many methane “torches” of this kind in Baikal.

Besides, remarkable natural oil shows were found in Lake Baikal - small spots of oil constantly float up to the surface in several sites of the water area and form iridescent films. In summer of 2005 such an oil show was found not far from the Barguzinsky bay. According to preliminary estimates, the amount of Baikal oil makes up about 4 tons per year. But it quickly gets destroyed by water microorganisms, and the water of Baikal stays pure already at a short distance from an oil show.

A large amount of foreign matters of Baikal are not related to the man and enter the Lake from the Selenga River. The researchers discovered: these substances are intensively processed in the so-called “barrier zones” – on the narrow stretches of the water area emerging in the places where the river’s and the lake’s waters mix under the influence of physical and biological factors which include a rapid change in the velocity of currents, temperature and phytoplankton growth, alongside with the work of microorganisms and deposition of suspended solid matter.

In a word, limnologists claim: the condition of the waters of Lake Baikal is not equilibrium, but stationary. 

The influx of foreign matters and their processing by the ecosystem of Lake Baikal are well balanced. Thanks to this, the concentration of main solid matters dissolved in the Lake is virtually constant at all depths and remains the same in the Northern, Middle and Southern basins of Lake Baikal.

This means that the Lake is self-regulated, which makes it possible to be optimistic about its future. However, human influence has still had its effect – far from beneficial - on Lake Baikal over last century.

Recent studies have shown: rivers running into the Lake in the vicinity of Listvyanka and Severobaikalsk contain coliform bacterium, its concentration is in some cases 120 times higher than the permissible level. The man is also guilty that nitrogen and phosphorus come into the water with the waste, these agents make up a nutritious environment for the sinister spirogyra – it is the name of an ordinary seaweed which has been heard of by everyone who is not indifferent to the preservation of the ecological environment of the “glorious sea”. Tons of spirogyra rot on Baikal beaches, alongside with this, the unique Baikal sponge dies, which gives some Baikal researchers a reason to talk about the Lake being on the verge of an environmental disaster.

In summer of 2010 limnologists first noticed the picture which is abnormal for Baikal: the abundance of filamentous algae that have been rare until very recently. And only a year later this atypical vegetation blossomed in the bays along the coastline displacing the endemic Baikal sponge. More than a dozen research expeditions have been held since that time, basing on them, limnologists have come to disappointing conclusions: spirogyra reproduces at an exponential rate and today it vegetates almost along the entire coastline.

In addition, spirogyra is now gradually moving to greater depths, where it creates a biomass comparable to that of macrophytes which are innate for Baikal. Due to such rapid growth of algae, for example, the spawning of the Baikal sculpins was threatened: the fish were simply unable to get to their nesting sites during the spawning period.

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In addition, spirogyra is now gradually moving to greater depths, where it creates a biomass comparable to that of macrophytes which are innate for Baikal. Due to such rapid growth of algae, for example, the spawning of the Baikal sculpins was threatened: the fish were simply unable to get to their nesting sites during the spawning period.
The death of the Baikal sponge which is one of the most famous endemics of the Lake has acquired the scale of a disaster. These are Baikal centenarians (the age of many sponges amounts to 150-200 years). Because of the above-mentioned changes, the sponges become sick, deform and gradually die. Today Lake Baikal already has places where no Baikal sponges live. 

Scientists have already discovered seven varieties of sponges’ diseases. And yet the reason that provoked the epidemic still has not been found.

In an attempt to find the answers to such difficult questions, scientists occasionally discovered other man-induced problems of the Lake. Thus, in 2010 toxic species of cyanobacteria were first registered in the area of Maloe More (“Small Sea”) and in the Barguzinsky bay. In 2015 scientists took samples directly from the sick sponge which can be met in bays. Molecular-genetic analysis showed that the samples contained saxitoxin belonging to the group of toxins with a paralytic effect. A high dose of the substance can paralyze respiratory muscles. The problem of concentration of saxitoxin in the Baikal water has not been solved for today. The researches are not yet finished. But the main answer is already evident: the man is one of the causes of the Lake’s environmental problems.

Spirogyra is abundant at the location of household sewage near Severobaikalsk. At the same time literally two steps above the place of sewage the section of the Baikal coast is absolutely divine and pure. By the way, the analysis of the composition of urban sewage of Severobaikalsk showed that up to 6 tonnes of mineral nitrogen had entered the Lake during four years; as it is known, the substance is the main nutrient of the above-mentioned spirogyra.

An increased concentration of phosphorus and nitrogen compounds was found in the water on the Southern shore of the Lake, in Listvyanka... It turns out that the man encircled Baikal, actively destroying ecological balance of the Lake both from the North and from the South. What can we say about the numerous tourists who make their contribution to the ecological imbalance?

It may seem: what harm can a tourist do to the Lake which is 25 million years old?

A separate tourist cannot do this. But in the summer season of 2014 more than 800 thousand tourists were registered at the ferry line leading to the island of Olkhon. It is only one summer, and we take only registered tourists.

This comes despite the fact that the main production (namely pulping) on the Baikal pulp and paper factory has been terminated since the autumn of 2013; this factory was considered the main polluter of the Baikal waters for nearly half a century.

There is a popular opinion: Baikal will see all us out. You cannot argue with this. But the dying Baikal sponge, stinking Spirogyra, the coastline – when you see all that, it is hard to believe that this Lake can be regarded as the purest one in the world. And the main thing is not to be considered pure, but to be actually clean.
Otherwise all these rousing flashy familiar figures of pride for Baykal are to be left to descendants as statistical samples of the past, not the present.
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Of course, the Lake does not care about the man who is so small on the scale of eternity passing on the shores of the Lake, almost unnoticeable. But the man should care about the Lake. We are a part of the Earth’s ecosystem ourselves. And as far as we live in the era of Lake Baikal and near it, we are responsible for it. The way it is responsible for us. This is symbiosis, a mutually beneficial co-existence of different elements of a single system.

And in this sense people and Lake Baikal have equal rights.

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