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620
Section: Biology
Baikal. Champagne. Kyoto...

Baikal. Champagne. Kyoto...

Putting in another way a well-known phrase, we can say that a drop of champagne — a beverage which starts its life on a grapevine, fills with solar energy and after a long chain of transformations gets into your glass — is an excellent model reflecting many of the processes that occur when live nature interacts with man. Among these processes is carbon dioxide circulation, now considered to be responsible for the global climate changes of the last decades, which have been such a troubling issue for mankind...

Studies of the history and current state of the climate and biosphere touch inevitably upon the problem of carbon dioxide concentration in the atmosphere. In recent years, a large number of high rank economists and politicians have been engaged in the discussion of this topic.

Why has СО2 attracted so much attention? During the last decades, the average annual temperatures on the planet have been increasing constantly — the so-called global warming is coming. Another distinctly pronounced trend is a higher concentration of СО2 in the atmosphere.

Mankind wants to get answers to the main questions: do the climatic changes observed result from the economic activities of people and does nature have a safety margin sufficient to withstand this interference? The number of scientific and periodical publications, serious economic documents and political protocols on the subject is enormous; any further discussion would hardly be worthwhile if the problem the scientists of our country had to tackle were not so critical.

Fuss around Kyoto

The matter is that after heated debates Russia adopted the Kyoto protocol, which came into effect on February 16, 2005. This treaty regulates countries’ activities in the area of atmospheric emissions of the so-called greenhouse gases and is aimed at decreasing the negative anthropogenic impact on the climate. For the first time in the history of international relations, it was suggested that specific market mechanisms should be applied to environmental problems.This is why we are speaking of СО2: the list of greenhouse gases controlled by the Kyoto Protocol includes, apart from carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride, but the baseline unit is one ton of carbon dioxide. It is this gas that serves as an equivalent, the concentration of other greenhouse gases is calculated as corresponding to carbon dioxide via relevant coefficients.

For each country, quotas for the emission of greenhouse gases are established. It is then up to a country to decide whether it will decrease the emission of a certain gas or buy missing quotas from another country in order not to hinder the development of the national economy. Whatever the case, one ton of carbon dioxide serves as the equivalent.

The Kyoto Protocol has a lot of adherents and a lot of opponents. The former assert that the climate becomes warmer because of higher carbon dioxide concentrations in the atmosphere. In fact, the sharp rise of СО2 concentration correlates with the temperature increase; and all the current climatic models, based on the estimates of the impact exerted by real anthropogenic emissions of carbon dioxide on global temperature, make predictions that agree well with the effects observed.

The opponents, in their turn, point to the fact that warming is primary and caused by natural factors, while the increase of atmospheric СО2 concentration is the result of global warming. The climatic system of the planet is very complicated and not completely studied, but indeed “heating” of the World Ocean should bring about a lower solubility of carbon dioxide in water and, consequently, its buildup in the atmosphere.

Evidently, it would be possible to answer these questions only after long-term and detailed studies which are being conducted by all scientific teams of the world.

What’s the price?

It is quite symbolic that the Kyoto Protocol was signed in this particular ancient Japanese city, which harbors one of the plainest and most mysterious creations of man – the Rock Garden.

A special meaning is embodied in the arrangement of rocks, so that one can see no more than 14 of them from any viewpoint, whilst the last, fifteenth rock always remains hidden from view. Possibly, in this way the designers of the Garden wished to convey to the visitors the Buddhist idea of infinity and inconceivability of the world, of the necessity to perceive the reality in a broader and unprejudiced manner.

The same can be said of the Protocol. Even though it is extremely difficult to be certain about the reasons of events and to make prognostic estimates, people who feel deeply responsible for the future of our planet have done their utmost for this document to be adopted. It was not an easy way to go, and representatives of the European Union, Japan and Canada — countries featuring highly “ecological” thinking and culture – have made great efforts to accomplish this. However, it happened so that it was up to Russia to make the final decision: “to be or not to be.” No doubt, it has made the right choice by signing the Protocol.

Thus the Protocol has been adopted. Its realization, however, will entail large expenses.

People familiar with finance are seriously alarmed at the calculations, which, although not claiming to be accurate, can nevertheless be relied upon as far as the order of magnitude is concerned. The actual concentration of СО2 in the atmosphere is about 377 ppm (number of gas particles per 1 million of air particles). If the current rate of emission is maintained, in ten years СО2 concentration will be about 405 ppm. If all the countries fulfill their obligations to observe the actions established by the Protocol, the СО2 concentration will be only 2–3 ppm less. This is within the error range typical of computation models.

Unfortunately, such is the inertia of our natural system. Reality is that only by the end of the century mankind would be able to achieve (and if the premises are not true, not to achieve) an appreciable result. Meanwhile, the actions developed to realize the Protocol are estimated to cost hundreds of trillions of dollars!

I cannot judge which point of view is closer to the truth. But I support the adoption of this important document, which is worth regarding as a new pragmatic religion of the 21st century.

However, religion, economics, and politics are not my competence. Let us now return to the core of the processes that occur in nature and to what scientists are doing today.

Baikal and a glass of champagne

Everybody knows the enjoyment of looking at a glass of champagne, in which myriads of bubbles ascend, sparkling in the sunlight or reflecting mysterious flames of candles.

We will come back to the champagne later, and now let us get down to the essence of the processes taking place in the glass: the bubbles are nothing else than carbon dioxide formed in the course of champagne maturation, whose partial pressure is higher than atmospheric pressure. The cork popping out opens a new phase in the life of champagne and carbon dioxide: gas exchange occurs between the surface of the liquid and the atmosphere.

This process has been the main subject of the investigations we carried out in the last few years at Lake Baikal. Before we pass on to specific measurements and results, I would like to make a general introduction.

Let us begin with the fact that everything living on the Earth exists thanks to and in spite of the Sun. What does life consist of? To put it shortly, of carbon, water and energy of the solar light. An enormous amount of radiant energy (almost 1.4 kw per 1 square meter of the surface) falls on the upper border of the atmosphere, which, as compared to the planet, is negligibly thin. This aerial envelope, whose active layer is less than 100 km thick, protects us from the fatal short-wave radiation, as it lets through a fair share of the falling visible light and absorbs partly the infrared (heat) radiation emitted by the Earth.

A simple calculation shows that if the Earth had no atmosphere, its steady-state temperature would be – 180С, which means there would be no life, as we understand it. However, the Earth’s atmosphere contains suspended particles (aerosols), clouds and a number of gases which make up a system regulating the radiation balance and, therefore, determining the weather in our common home. As a specialist in the area of atmosphere optics, I could reason for a long time about the role of certain atmospheric components in climate regulation and, even for a longer time, about the work of the Institute of Atmosphere Optics, Siberian Branch, Russian Academy of Sciences (IAO SB RAS), on the complex study of atmospheric properties. Instead, I would like to return to СО2 and Baikal and consider the issue of the sources and “sinks” of carbon dioxide as a basic component of the atmosphere.

Carbon dioxide takes part in the process of photosynthesis: formation of complex organic substances essential for life by higher plants, algae, and photosynthetic bacteria at the expense of light energy. In everyday life, few people realize that coal, petroleum, gas, plants, animals and even human beings can be considered as products of photosynthesis, that is, as accumulated energy of the Sun.

It is clear that photosynthetic processes going on in the atmosphere involve, in addition to СО2, other carbon-containing gases, but their concentration in the atmosphere and in the World Ocean is lower by an order of magnitude. Relevant investigations are under way in various geographic zones, the main concepts of СО2 cycle on the level of the planet have already been developed, and now the attention of specialists is focused on the study of processes occurring at the regional level. And here, at last, we are coming back to Baikal.

BAIKAL! How much this sound suggests…

Approaching Baikal, one normally feels an unusual elation, inexplicable joy and light dizziness, as after the first sips of good champagne. Having visited this land a number of times, you come to understand that Baikal can do anything: fascinate and frighten, seduce and push away. The only thing which it cannot do is to bore you. This was a lyrical digression, however, and now let us get down to practice. The choice of Baikal as an object for the study of gas exchange was attributable to more than one reason. First, the overwhelming majority of modeled scenarios related to possible sources and sinks of carbon dioxide missed fresh-water reservoirs. Second and more important, the properties of this geographic region are unique.

Taking into account the benchmark purity of Baikal water, one can quite reliably separate physical, chemical and biological components of the complex process of gas exchange in the system “water — atmosphere”. This is practically unachievable in field observations held at other locations and highly problematic even on the laboratory scale.

Another important point, frequently ignored, is that the water temperature in the lake and corresponding state of the aquatic ecosystem respond principally to global climatic changes in our hemisphere, while the composition and properties of lower atmospheric layers are mainly affected by local processes.

And the most important point. Long before the beginning of our experiments in collaboration with the Limnology Institute, Siberian Branch, Russian Academy of Sciences, (LIN SB RAS), the experts of this Institute had conducted a vast long-term investigation of water composition and its relation to gas exchange processes. In fact, gas exchange is an interdisciplinary subject requiring combined efforts of physicists, chemists, biologists and mathematicians. (For example, try to describe quantitatively, on your own, the complex of processes and physico-chemical reactions which turn a sown grape seed into the noble beverage!)

Starting the studies of the atmosphere, we understood that this work was based on a huge pyramid of knowledge and that we were to add a tiny apex to this pyramid, which would emerge above the water. Our aim was to reveal and describe, in a limited set of experiments, the relation of carbon dioxide fluxes to the chemical composition of water and to the “live component” of biocenosis, as well as to determine their seasonal variation. The next step was to evaluate, on the basis of knowledge accumulated earlier, the role of Baikal as a reservoir of carbon dioxide and to try to forecast how this system would behave in the situation of global warming and constant increase of carbon dioxide concentration in the atmosphere.

Combined team of SB RAS

An excellently equipped research field station of the Limnology Institute, SB RAS, near the village of Bol’shie Koty, was chosen for the investigations. Our main expeditionary team for the study of gas exchange consists of chemists from LIN, physicists from IAO, and biologists from Irkutsk who participate in laboratory tests of water samples. It is pleasing that in the last years the circle of enthusiasts has expanded: in 2004, specialists in fluorescence from the Institute of Computational Modelling, RAS, Krasnoyarsk, joined us; and in 2005, our colleagues from the Laboratory of Radiophysics of the Physical Problems Department of the Buryat Scientific Center, RAS, Ulan-Ude.

Measurements are conducted all year round in cycles: continuous investigations are not yet possible because of the scarcity of funding. It should be mentioned that current studies are supported mainly by the LIN SB RAS and IAO SB RAS, as well as expeditionary grants of SB RAS and contract of the RAS Program “Water resources, dynamics and protection of underground waters and glaciers”, headed by Academician M. G. Khublaryan.

We chose the chamber method as the main approach to measuring daily rhythms of gas exchange and to estimating fluxes at the water-atmosphere interface. It was not a blank page start: we had acquired an experience of this kind in the investigation of similar processes at Bolshoye Vasyuganskoye Swamp, in collaboration with the National Institute for Environmental Studies, NIES, Japan

(The Japanese team was headed by our good friend Doctor Gen Inoue).

The idea of the method is simple: a transparent chamber with no bottom floats over a patch of water and records periodically the content of the gas studied. Variations in gas concentration within a certain time lapse allow us to estimate the magnitude of the flux. For this purpose we use two floating chambers. One of them is completely isolated from the surrounding atmosphere and provides practically continuous record of daily rhythms of variation of carbon dioxide concentration in the near-surface layer of the atmosphere. The second chamber functions in the regime of automatic ventilation, thus allowing the correct hourly estimate of СО2 flux.

To adapt this method to the specific conditions of the aquatic surface, we had to “train” the chambers to “sail” with confidence. To this end, a number of appliances designed to hold the chambers in a fixed place in rough sea conditions were developed (the wind regime of Baikal is very changeable). However, even our anchors did not ensure complete security: several of our chambers broke against littoral rocks, and in each expedition we had to take a cold bath in Baikal water.

Carbon dioxide concentration, temperature, relative humidity and wind velocity were recorded by the weather mast twenty-four hours a day. Water samples were collected, at three-hour intervals, at two stations situated at the depth of 2 and 5 meters. Whereas the job of the physicists was practically over once the equipment had been mounted and launched (the rest of the work was done by computers), our lady chemists had a harder time. We could take a rest as soon as the usual portion of Baikal water was delivered to the laboratory, while the chemists’ intense work only started: measuring water acidity and temperature; concentration of dissolved oxygen, carbon dioxide and hydrocarbonate ion; content of biogenic elements; and so on.

In every expedition such intensive work took approximately from ten days to two weeks. However, our team never lost heart and found time to relax.

How Baikal breathes

At present, the daily rhythms of gas exchange and variation of the chemical composition of surface water have been studied sufficiently well. Variations in gas exchange intensity were found to depend on the season of the year and on the time of the day. It is no news that in the warm season at sunrise the Baikal biota starts its work on the uptake of carbon dioxide from the atmosphere; whilst after sunset the direction of СО2 flux is reversed so that the gas is returned to the atmosphere.

Daily oscillations of carbon dioxide and oxygen concentrations are of the opposite sign; daily variations in the concentration of dissolved gases and biogenic elements are affected primarily by photosynthesis of planktonic and bottom-living algae, as well as by the aerobic decay of organic matter.

The first winter experiments gave quite unexpected results. Without additional studies it was hardly possible to say whether Baikal breathed in winter. We found that at sunrise and at sunset, when the ice-crust was thin, there occurred a sharp discharge of carbon dioxide to the atmosphere, and the chemical composition of the surface water changed significantly. This contradicted, to a certain extent, the established opinion that in winter there was no gas exchange between Baikal water and the atmosphere.

The experiments carried out in 2005 showed no gas exchange in the period when the ice was of maximum thickness and soaked in meltwater. Such variability of processes and phenomena is rather promising since it provides food for thought and encourages further experiments. For the time being, there is no point in describing the results in more detail since our investigation is far from being completed: no more than one-third of the way has been covered; yet the way to go is clear-cut

Above all

After all, what is the aim of our investigation on the whole and of this article in particular? In any event we are going to continue the studies according to our academic programs and driven by the curiosity and excitement one feels when solving problems resulting from a more profound understanding of gas exchange.

However, it is evident that in a few years the amounts of carbon dioxide emitted or utilized can give rise to serious disagreement between the countries. In order to be able to participate competently in this kind of conflicts and play the role of an expert, we have to carry out, today, comprehensive studies and monitoring of variations in the concentration of greenhouse gases on our territory. In Siberia, such studies have been fairly intensive; moreover, Russian scientists involved in them have always made part of international teams and projects.

Unfortunately, so far Siberia has no national station for greenhouse gas monitoring. For this reason, in the event of a conflict we would be able only to watch. Coming back to the financial issue, I would like to stress that the extremely high price of even a small deviation from the quota (1–2 ppm) imposes special demands for the accuracy, regularity and quality of observations, which most fundamental works do not require.

Therefore, projects of this kind require, apart from traditional scientific approaches, massive efforts aimed at organizing specialized observatories and at obtaining international certification. It should be noted that the Siberian Branch of RAS has everything needed to conduct high-level research and observations, at least as far as this region is concerned.

Let us come back to Baikal. The widely used phrase “Baikal is a natural laboratory” is supposed to mean that Baikal harbors a lot of intriguing mysteries, which is true, but there is another aspect which escapes the attention of scientific community. The Baikal region is an ideal laboratory for the investigation of global changes in the environment. It comprises the unique, largest lake in the world; a ramified river system; mountains; practically every landscape type one can see in Siberia; and a set of large industrial objects. There is no doubt that correctly planned investigations would give scientific results important not only for the Siberian region, but for the understanding and forecasting of global processes occurring in the environment interacting with man.

It is time to begin, and I hope that these lines will help to speed up the developments. I am sure that the young scientists who make up the core of our team will be able to say whether the water of Baikal will remain similar, as far as the natural processes taking place in it are concerned, to champagne, which harmoniously combines organic substances and carbon dioxide. The less attractive alternative is ordinary carbonated water which this natural wonder can turn into as a result of human activities that artificially saturate the atmosphere with СО2.

I wish we could finger up-to-date equipment, see a well instrumented and internationally recognized Siberian Observatory, and have a payroll which would support the opinion that our work is interesting not only for us but also for our homeland.

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