Translated material
Salted lakes as factories and as an ecosystem
In 1986, a limnological disaster occurred in Cameroon, in the area of Lake Nios. A large amount of carbon dioxide came to the surface of the lake; About 1.7 thousand inhabitants died of suffocation, losses among livestock amounted to 3.5 thousand. This was not the first and not the only tragedy associated with complex biophysical processes in reservoirs. There are similar lakes in Russia. Olga Orlova, in the program “Hamburg account” on the public television of Russia, found out about how far limnologists advanced in understanding the riddles of fresh and salty lakes. Biol. Sciences, Vedas. scientific. sore. Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences Yegor Zeroeev .
Egor Zerueev was born in 1972 in the village of Irbeyskoye, Krasnoyarsk Territory. In 1994 he graduated from the Faculty of Physics of Krasnoyarsk State University. In 1998 he graduated from the Faculty of Sciences of the Environment and Policy of the Central European University in Budapest. In 1999 he defended his thesis. Scientific interests: ecosystems of salted lakes, the role of environmental factors in the regulation of the population dynamics of zooplankton, mathematical modeling of population dynamics, chemical communications in aquatic ecosystems. Vice-President of the International Society for the Study of Salted Lakes. For more than 10 years, he has been engaged in the popularization of science. Scientific editor of a series of popular science books "Laboratory of Red Yar". Laureate of the diploma of the Club of Scientific Journalists as part of the Enlightener Award, 2010.
- Egor, you are a limonologist. And one of the areas of your activity is the study of salted lakes. For those people who taught geography in a Soviet school, with the phrase “salted lakes”, Elton and Baskunchak and the sad fate of the Aral Sea immediately come up in their memory. But it was a long time ago. Your biophysics institution is in Krasnoyarsk. And how do you study salted lakes from Siberia? How many objects of study on the territory of our modern Russia are in general?
- Salted lakes are generally found on all continents.
- Russia is not deprived?
- And we are not deprived, because the salty lakes are typical for the zone of the so -called arid (in other words, dry) climate: where the amount of precipitation is less than the number of fumes. By and large, this is the whole steppe. And our steppe extends from the Caspian to Chita, Transbaikalia and Mongolia. Therefore, not far from Krasnoyarsk in Khakassia and in the south of the Krasnoyarsk Territory rather salty lakes. Novosibirsk region, Transbaikalia ...
- That is, you do not experience a deficit in these reservoirs.
- We do not experience a shortage. There are many of them. And, moreover, we are biophysicists. It doesn’t matter to us what the size of the lake is, but the general principles of its functioning are important. Even a small salty lake may be enough to study the general laws of behavior of such systems.
With the inventory of lakes, by and large, a problem in the world. I somehow like a global scale more, not Russian. Still, scientists operate not with national units, but geographical. And there are still debate, how many salty lakes in the world. It is believed that the number of salted lakes is approximately equal to the number of fresh lakes (slightly less, but uncritical). Even this is already amazing. Because it is usually believed that there are more fresh lakes than salty.
- At least the inhabitants think so.
- Strictly speaking, there are no exact assessments - for the whole world, and for Russia too. Very often salty lakes change in their size and can sometimes disappear, and sometimes appear.
- But what is the fundamental value of the study of these reservoirs? Why is there such an interest in them? Why are they allocated in a separate group?
- There are several fundamental tasks. If we talk about hypericated lakes, there are unique bacterial communities. Bacteria living with high salinity do not use oxygen, but other compounds, they participate in the cycles of sulfur, iron, nitrogen, carbon. And these are exits to biometallurgy, new enzyme systems, interesting biotechnologies. In salty lakes, you can look for unique types of bacteria, pull out unique genes from them, sew them into organisms that are used in bioreactors, and make some very effective treatment facilities, for example. They will process nitrogen compounds. This is one, a narrow class of tasks.
The second, fairly wide class of tasks is due to the fact that in principle we must understand how complex ecosystems function. And salted lakes are very often stratified, that is, they are divided into layers of water of different densities. These layers are not mixed. And such non -interruption leads to unique conditions. For example, at the top a layer of less sun water, a layer of more salty water below. Oxygen ends below. Gases begin to accumulate there (for example, hydrogen sulfide). On the one hand, unique bacteria live there. On the other hand, if the water is mixed, then these gases fall into the upper layers, kill all living things there (fish and crustaceans for starters), the quality of water will sharply worsen.
And there are a lot of such ecosystems, where water is not mixed. Starting from the ocean, in which there are oxygenic zones (and the area of these zones is now growing, including due to climate change), and ending with the Black Sea, where huge stocks of hydrogen sulfide at the bottom, or some small lake in Khakassia. We are now exploring just such a lake called: its length is 900 m, width is 500 m, the maximum depth is about 6 m. The systems are different in scale, and in terms of the principles of the organization they are very similar, from the point of view of a physicist. Studying the processes of mixing and stability of a small lake, we hope to scale them to large systems.
- How are the salty lakes form?
- Differently. But if we are talking about the internal reservoirs that are inside the continents, the steppe lakes, then the formation mechanism is as follows: a large amount of water flows from the water collection, the water evaporates, the salt remains. Over time, it concentrates in this reservoir, and now it has become salty. If the lake will continue to decrease, then salinity will increase, because the salt does not disappear anywhere. An example is the Aral Sea.
- There is an intermediate stage when the inhabitants of fresh waters in the salty lake cannot live, and the inhabitants of the sea waters cannot yet. And who lives there then?
- There live organisms who managed to adapt in order to live with these salins. Here is also a separate topic of a very big dispute. The concept of critical salinity was also developed by Russian limonologists. They argued that there is a failure in biodiversity on certain salins. And now, including in Russia, there are studies that say that failure is just associated with the incorrect life of life, and in fact it seems to be not, because life also occupies this niche. There is still a lot of disputes, there is this critical salinity or not.
In any case, we must understand what life is in salt or fresh water. If we live in fresh water, then we need to develop the mechanisms of osmoregulation, which do not allow salts from the body to enter the environment. There are compounds inside the body, in fresh water they are not. So, they will diffuse, which means they need to be kept. If we live in salt water - on the contrary, so that the salt does not get into the body, you need to download it back.
Accordingly, organisms that could live both in a hypersollah lake and in the fresh lake do not exist. They are adapted either to one or to the other.
- Now let's move on to the person. We are all concerned primarily by the amount of fresh water on the planet. What does the study of salted water bodies signal us in connection with the problem of fresh water? Is there a threat that those reservoirs that are fresh today will become salty and we will lose these precious stocks for us?
-Since the year before last, the Vice President of the International Society for the Study of Salted Lakes. And annually I make a brief overview of the most interesting scientific articles on the topics of salty lakes. Last year, the most quoted article, and not only among loders, but in general among water ecologists, was an article that predicts the salinization of so many fresh lakes in connection with a change in climate [1]. First of all, this is relevant for the Mediterranean zone. Where, thanks to a change in the climate, the balance of evaporation and drain changes, evaporation begins to exceed the drain, and then more water evaporates from the lakes than they entered, the salts are concentrated, the lakes become more salty.
A similar article was released in Arctic lakes in Canada [2]. There are similar processes. This, of course, is not yet high salinity, but, nevertheless, the number of dissolved ions increases due to the fact that evaporation begins to exceed the amount of receipt.
The third problem is related to human activities. For example, in the States, salt is very often used to sprinkle roads in winter, then this salt enters the water bribe, then it reaches reservoirs, to the lakes, it concentrates there, and they also become more salty. Therefore, the problem of salinization exists, of course. And you need to understand what will happen in general with our number of fresh water reserves in the future.
I made a comic assessment for Lake Baikal. Pretty funny assessment. It is a little speculative. If Lake Baikal is dashed to the size of the Novosibirsk reservoir (the "reservoir" also sounds large, but we understand that Baikal is very huge), then it will be about salinity about the Dead Sea. Of course, such a scenario is now difficult to present. It is almost impossible. But in any case, from any reservoir you can make a reservoir with increased salinity if desired. And now we understand that including in Lake Baikal there is a slight decrease in water level. It is precisely due to the fact that the amount of water entering it with water rivers decreases either due to local climatic changes, or due to human activity.
Once every three years, a conference of the International Society for the Study of Salted Lakes is held. Next year she will be in Ulan-Ude. We spend it in Russia. And we chose the slogan of our conference "The study of salted and fresh lakes - in search of a point of contact." Because we believe: the processes of assessing the water balance, how the ecosystem behaves with even a slight change in the concentration of salts, is relevant for both fresh lakes and salty. But here you need to look together.
- From the point of view of the national economy, is there such a problem that we lose fresh water reserves? Do we need to worry?
- We rather do not lose them, but pollute them in huge quantities. In general, we need, of course, to worry about the quality of fresh water. It, of course, can be cleaned, but the purification rate is lower than our pollution rate.
- Why am I asking? Infinitely discussed at different economic forums of ways to get out of the crisis of Russia. So, talking about how to turn the economic system, making it open and so on is very difficult. It is necessary to change the power, launch democratic processes so that there is competition and so on ... And, for example, get off the oil pipe and transfer to a freshwater pipe - these scenarios are already being discussed. How do you feel about them? To the fact that Russia in the future will become a leading exporter of not oil, but fresh water? Due to the fact that they all end there, but will we still have?
- Fresh water is now traded very actively in any case. We are now going to the stall, we buy a bottle of water and drink it. And the fresh water market is actually huge. And a large number of corporations (Russian, foreign) is doing this. If we talk about large -scale sales, at the oil level, I do not really believe in it, because it is very reminiscent of projects to transfer Siberian rivers to Asia.
“But you know that our country is capable of this?” In general, we can implement global projects. The story showed this.
-We can realize them. But you need to understand that if it has left somewhere, then it will not arise there again. Examples of the same Aral Sea and other reservoirs show that so far we are not yet ready for such global management at the level of macro -regions in terms of maintaining the quality of life in the region that we transformed.
Holland has a more or less successful experience, but there are completely different scales. What is needed for this? In particular, what we do. For this, of course, we need very high-quality mathematical models that allow us to understand how the lake behaves ... The task of ecology by and large is to predict the behavior of the ecosystem with a variety of external influences and say what will be in some kind of visible temporary horizon. Everything is very simple, on the one hand. But this requires adequate tools, first of all, mathematical, which allow decisions, including politicians and economists.
For example. Now the Urmia Lake in Iran dries in the same way as the Aral Sea has dried up with us. A large number of population is left without water. The fish died because the salinity of the lake has grown. The tourism industry and the fish industry collapsed. The lake has gone, salt, salt storms, the wind spreads, the soil is salted, agriculture falls. A large -scale problem.
There is still no exact good balance model, which allows you to predict the amount of water that will go there with high reliability, the amount of water that will evaporate. Although the efforts are spent very large. It would seem that this is a simple task, but it is non -trivial. Therefore, without solving such issues, it is simply to be transferred to the transfer of some large volumes of water-this is a pure utopia that I would not advise doing, simply because the consequences are unpredictable.
- How much time should it take to make the lake from the living and the acting almost muffled and so much salted?
-The fact of the matter is that for salty lakes these are very fast times, because the Aral Sea in almost 20 years was very sharply impoverished and divided into several reservoirs, in which life, what it was, disappeared. 20 years is not enough. The salty lake of Mar-Chikta in Argentina (a very large lake, we were there too) over the past 100 years have experienced, in my opinion, two or three cycles of increasing and lowering the water level, which sequentially destroyed the entire tourist industry, then destroyed the entire fishing industry. And now they no longer know what to do, because it seems that the lake has returned to more or less understandable boundaries, fish appeared there again, but now they are already afraid to do something active, because they do not know how it will behave in the nearest 10-15-year future. 10 years - a short time. A person does not have time to adapt and is not ready for the fact that the environment will radically change in 10 years.
- You go on expeditions not only in Russia, but also to other countries. Tell us about the most outlandish lakes where you managed to visit.
- We drove part of the Tibet, the tsaydam cavity, looked at a fairly large number of salty lakes. The Chinese have their own path.
- And how, by the way, do the Chinese solve the issue of salting?
- And the Chinese solve this issue very simple. Salted lakes are a huge base of mineral raw materials. Therefore, the Chinese consider salty lakes as ponds filled with a large amount of dissolved salt. From the salty lake you can get potassium, magnesium, lithium, sodium - a very large number of compounds. Therefore, they around their salty lakes, especially in a deserted Tibetan area, put several huge plants that produce millions of tons of salt. They sell in the market and thereby raise their economy.
- A utilitarian approach.
- Yes, the lake is like a factory. The second approach, a contrast, is a lake as an ecosystem.
The colorful researcher of salty lakes Maria Farias from Argentina explores stromatolites. Where a stream of fresh water flows into the lake, minerals begin to fall out. Cyanobacteria grow on these minerals, then layers of minerals are layered. And it turns out such a biocosal structure, which is considered a prototype of first life on Earth. The most ancient stromatolites are billions of years. These are one of the first bioorganic and bio -organic formations. She explores these stromatolites in lakes in the Andes. These are high -mountain lakes, very rich in lithium. They are interested in commercial structures. Most lithium is in salty lakes or in salt marshes. Actually, they get them there. We evaporate water, take lithium and sell. Everything is very simple. Therefore, on the one hand, these lakes are interesting as unique artifact ecosystems. There is a bridge in both astrophysics and in astrobiology, because it is a highland, an increased flow of solar radiation, and other pressure. In general, extreme conditions. Against the background of studying these reservoirs, you can learn something new about Mars. On the other hand, there is also economic interest. Maria Farias managed to declare this zone to the reserve at the government level. And there now all work is stopped.
There are two such contrasts: either the protected system, or the extraction of minerals ...
- And in Russia what approach? Does our salty lake become a factory? Or do we still have protected ecosystems rather?
- We have salt marshes where we get salt. This is, for example, Baskunchak. И там, конечно же, своего рода соленые фабрики. Там столетняя, даже почти тысячелетняя добыча соли. This is fine. Кроме того, соленые озера зачастую — это еще и курорты. Лечимся и отдыхаем. По крайней мере в Сибири на многих соленых озерах находятся курорты. И многие эти озера так или иначе охраняются.
И еще одна вещь спасает многие соленые озера. Зачастую это точки миграции птиц. Болотноводные угодья защищает Рамсарская конвенция. И очень часто это как раз зоны соленых озер. Поэтому многие соленые озера объявлены заповедными. Степная зона, птички летят, больше негде остановиться.
Так что тут ответвления в самые разные стороны.
— Самый удивительный эффект, который Вам удалось наблюдать на соленых озерах?
— Самый удивительный эффект связан не с экспедицией, а с началом нашей работы. Мы тогда еще ничего не знали. Мы вытащили из глубины озера банку, она была розового цвета, и мы долго выясняли, кто не помыл банку перед отбором проб. Только потом мы узнали: это нормально, что на определенной глубине живут серные пурпурные бактерии, которые формируют такие тонкие слои. Они похожи на растворенную марганцовку. А тогда мы были совсем глупые, аспиранты, физики, которые в первый раз пришли на озеро. Все банки белые, а эта — розовая…
— Теперь Вы уже опытный лимнолог, который много повидал. Кто у Вас самый любимый обитатель соленых озер?
— Самый любимый обитатель — это, наверное, тот, кого я использовал для подготовки своей кандидатской диссертации. Маленькие ветвистоусые рачки Moina живут и в пресных, и в солоноватых озерах, и они удивительны для окружающих. Они могут размножаться половым способом, могут размножаться бесполо, они образуют специальные яйца, которые можно высушить, заморозить, облучить, поместить в насыщенный раствор какого-нибудь токсиканта, а потом это яйцо положить в чистую воду, и из него вылупится замечательный живой рачок.
— То есть это не рачок, а птица Феникс?
— Да, их даже в космос отправляли. Они там болтались на поверхности МКС, потом вернулись обратно, и из некоторых яиц вылупились рачки.
— Экспедиция Вашей мечты?
— Мы тут с моим знакомым научным журналистом Алексеем Паевским хотим замутить экспедицию «Вся соль России» по соленым озерам от Крыма до Востока. Это было бы, наверное, здорово.
Egor Zeroeev
Olga Orlova talked
2. http://onlinelibrary.wiley.com/doi/10.1111/gcb.12759/full