How can trees extract moisture in the pacific northwest

Pacific Northwest trees struggle for water while standing in it

CORVALLIS, Ore. - Contrary to expectations, researchers have discovered that the conifers of the Pacific Northwest, some of the tallest trees in the world, face their greatest water stress during the region's eternally wet winters, not the dog days of August when weeks can pass without rain.

Due to freeze-thaw cycles in winter, water flow is disrupted when air bubbles form in the conductive xylem of the trees. Because of that, some of these tall conifers are seriously stressed for water when they are practically standing in a lake of it, scientists from Oregon State University and the U.S. Forest Service concluded in a recent study.

It's not "drought stress" in a traditional sense, the researchers said, but the end result is similar. Trees such as Douglas-fir actually do better dealing with water issues during summer when they simply close down their stomata, conserve water and reduce their photosynthesis and growth rate.

"Everyone thinks that summer is the most stressful season for these trees, but in terms of water, winter can be even more stressful," said Katherine McCulloh, a research assistant professor in the OSU Department of Forest Ecosystems and Society.

"We've seen trees in standing water, at a site that gets more than two meters of rain a year, yet the xylem in the small branches at the tops of these trees can't transport as much water as during the summer," McCulloh said.

The ease with which water moves through wood is measured as the "hydraulic conductivity," and researchers generally had believed this conductivity would be the lowest during a conventional drought in the middle of summer. They found that wasn't the case.

"We thought if there was a serious decline in conductivity it would have been from drought," said Rick Meinzer, a researcher with the Pacific Northwest Research Station of the USDA Forest Service, as well as OSU. "It was known that air bubbles could form as increased tension is needed in the xylem to pull water higher and higher. But it turns out that freezing and thawing caused the most problems for water transport."

Studies such as this are important, the scientists said, to better understand how forests might respond to a warmer or drier climate of the future. And although this might imply that these conifers could be more resistant to drought than had been anticipated, the researchers said it's not that simple.

"If the climate warms, we might actually get more of these winter cycles of freezing and thawing," McCulloh said. "There's a lot of variability in the effects of climate we still don't understand.

"One of the most amazing things these trees can do is recover from these declines in conductivity by replacing the air bubbles with water," she said. "We don't understand how they do that at the significant tensions that exist at those heights. We're talking about negative pressures or tensions roughly three times the magnitude of what you put in your car tires."

When the field research on this study was done in 2009, the area actually experienced a historic heat wave during August when temperatures in the Willamette Valley hit 108 degrees. During such extreme heat, trees experienced some loss of hydraulic conductivity but largely recovered even before rains came in September. By contrast, greater loss of hydraulic conductivity was observed in the middle of winter.

The study was done at the Wind River Canopy Crane Research Facility, and published in the American Journal of Botany. The research was supported by the National Science Foundation.

"The commonly held view is that the summer months of the Pacific Northwest are extremely stressful to plants," the researchers wrote in their conclusion.

"Yet, our results indicated that the winter months are more stressful in terms of hydraulic function, and suggest that perhaps an inability to recover from increase in native embolism rates over the winter may cause greater branch dieback in old-growth trees than shifts in summer climate."

Reliance on stored water increases with tree size in three species in the Pacific Northwest | Tree Physiology

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Tree Physiology, Volume 23, Issue 4, March 2003, Pages 237–245, https://doi.org/10.1093/treephys/23.4.237

Published:

01 March 2003

Article history

Received:

16 May 2002

Accepted:

30 August 2002

Published:

01 March 2003

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In tall old forests, limitations to water transport may limit maximum tree height and reduce photosynthesis and carbon sequestration. We evaluated the degree to which tall trees could potentially compensate for hydraulic limitations to water transport by increased use of water stored in xylem. Using sap flux measurements in three tree species of the Pacific Northwest, we showed that reliance on stored water increases with tree size and estimated that use of stored water increases photosynthesis. For Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), water stored in xylem accounted for 20 to 25% of total daily water use in 60-m trees, whereas stored water comprised 7% of daily water use in 15-m trees. For Oregon white oak (Quercus garryana Dougl. ex Hook.), water stored in xylem accounted for 10 to 23% of total daily water use in 25-m trees, whereas stored water comprised 9 to 13% of daily water use in 10-m trees. For ponderosa pine (Pinus ponderosa Dougl. ex Laws.), water stored in xylem accounted for 4 to 20% of total daily water use in 36-m trees, whereas stored water comprised 2 to 4% of daily water use in 12-m trees. In 60-m Douglas-fir trees, we estimated that use of stored water supported 18% more photosynthesis on a daily basis than would occur if no stored water were used, whereas 15-m Douglas-fir trees gained 10% greater daily photosynthesis from use of stored water. We conclude that water storage plays a significant role in the water and carbon economy of tall trees and old forests.

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California Deserts

Coachella Valley Conservation Area in the Colorado Desert

The California Deserts have a unique ecosystem and habitat, a socio-cultural and historical collection of "Old West" legends, neighborhoods and communities, and constitute a popular tourist region of dramatic natural features and recreational development. All deserts are located in the east. Southern California, in the Western part of the USA.

Geography
- 1.1 Desert Mohava
- 1.2 Colorado desert
- 1.3 Large pool desert
2 Ecology and climate
3 History
5 Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations recommended also

Geography

^[1]^:408 The Mojave Desert is bounded by the Tehachapi Mountains in the northwest of the San Gabriel and the San Bernardino Mountains in the south, and extends east to California's borders with Arizona and Nevada; it also forms parts of northwestern Arizona.

The Colorado Desert lies in the southeast corner of the state, between the Colorado River and the Transverse Ranges, and continues into Mexico and Arizona to the south and east (as named the Sonoran Desert). The Great Basin Desert lies immediately east of the Sierra Nevada and extends east into Nevada.

Deserts cover all of Imperial County, southern and eastern Inyo County, eastern Mono County, Los Angeles County, Kern County, San Diego County, and Riverside County, and much of northern and eastern San Bernardino County. The main urban population of western San Diego County, Orange County, the Inland Empire, and Greater Los Angeles over the high mountains towards the Pacific Ocean.

Mojave Desert

Main article: Mojave Desert

Topographical boundaries include the Tehachapi Mountains to the northwest, and the San Gabriel and San Bernardino mountain ranges to the south. The boundaries of the mountains are quite clear, as they are delineated by two of California's largest faults, the San Andreas Fault and the Garlock Fault. ^[1] ^:411 The Mojave Desert in California includes the High Desert region, the region. In the Great Basin, scrub steppe lies north of the Mojave Desert; the warmer Sonoran Desert and its subregion, the Colorado Desert, lie to the south and east.

Desert landscape in the Mojave Desert

Colorado Desert

Main articles: Colorado Desert and Sonoran Desert

The Colorado Desert is the northwestern portion of the larger Sonoran Desert that stretches across southwestern North America. The Colorado Desert region covers approximately 7 million acres (2,800,000 ha), stretching from the northwestern border of Mexico in the south to the highland Mojave Desert in the north, and from the Colorado River in the east to the Laguna Mountains of the Peninsular Ranges in the west. The area includes heavily irrigated Coachella, Palo Verde, and the Imperial Valleys. The Sonoran/Colorado Desert in California includes the Low Desert region, the edge.

Great Basin Desert

Main article: Great Basin Desert

The Great Basin Desert is the only "cold" desert in the country where most of the precipitation falls in the form of snow. The Great Basin Desert exists because of the "rain effect" created by the Sierra Nevada of eastern California. When the prevailing winds from the Pacific rise over the Sierra, the air cools and loses most of its moisture as rain. By the time the wind crosses the mountains and descends from the opposite side, they become very dry and absorb moisture from the surrounding area. This drying effect is responsible for the creation of the Great Basin Desert. ^[2]

Ecology and climate

The California desert region is characterized by low rainfall caused by the rain shadow of mountain ranges to the west of the desert region. The Mojave Desert receives 3 to 10 inches (76–254 mm) of precipitation per year, while the Colorado Desert receives 2 to 6 inches (51 to 152 mm). ^[3] The driest place in California is Death Valley, averaging 1.5 inches (38 mm) of precipitation per year. ^[1] ^:406 California desert soils also tend to be alkaline, which increases drought stress for plants. ^[1] ^:408

Joshua trees are characteristic of the Mojave Desert

The Mojave Desert is considered a high desert because the altitude can reach 11,000 feet (3,400 m). ^[3] The Mojave Desert is characterized by the presence of Yucca brevifolia , the Joshua tree, which, as an indicator species of the Mojave Desert, extends southeast into Mojave County, Arizona, and even beyond, all parts of northwest Arizona. Other common plants of the Mojave Desert include: creosote bush, black brush, Greasewood, and salt marsh. Host at high altitudes Western Juniper and Piñon Pine. ^[3]

The Colorado Desert is a low desert with an elevation of −230 to 1000 feet (−70 to 305 m) above sea level. ^[3] Unlike other California deserts, the Colorado desert receives a lot of rain. North American monsoon in August-September. ^[1] ^:413 Colorado desert hostas saguaro cactus, Sonoran creosote bush, and Salton Sea salt marsh. ^[3]

The Great Basin Desert in California can also reach 11,000 feet (3,400 m). ^[4] Plants in the Great Basin Desert are well adapted to harsh environments. These plants include Big Wormwood, Piñon Pine, Utah Juniper, Low Wormwood, Shadscale, and Bristle Pine. ^[4] Wormwood, a very common inhabitant of the Great Basin, is well adapted to this area. The root system of the great sagebrush can be up to 90 feet in circumference. This adaptation allows the plant to collect as much water as possible when it rains. Mormon tea has modified leaves. The leaves are very small and are not the main site for photosynthesis. The chlorophyll-filled stems carry out primary photosynthesis. The four-winged saltbush draws salt through its leaves to prevent the accumulation of deadly salts in the plant. Plants in the alkaline plains have a high internal salt concentration and are able to extract water that other plants cannot. ^[5]

Common California desert animals include the desert bighorn sheep, desert kit fox, coyote, spotted skunk, spotted bat, black-tailed rabbit, ground squirrels, kangaroo rat, white-footed mouse, and desert tortoise. ^[3]

History

Prior to European exploration of North America, Native American tribes such as the Mohave (in the Mojave Desert), the Chemeuewi (in the Great Basin Desert) and the Quechan (in the Colorado Desert) were hunter-gatherers living in the Californian deserts. ^[6]

European explorers began exploring deserts from the 18th century. Francisco Garces, a Franciscan friar, was the first explorer of the Colorado and Mojave deserts in 1776. ^[7] Garces recorded information about the original inhabitants of the deserts.

Later, when American interests spread to California, American explorers began to explore the California deserts. Jedediah Smith traveled through the Great Basin and Mojave deserts in 1826, finally reaching Mission San Gabriel. ^[8] ^[9] John C. Frémont explored the Great Basin, proving that water does not flow out of it into the ocean, and provided maps that forty-nine had previously traveled to California. ^[10]

The California Gold Rush began economic activity in the California deserts. Mining for silver, gold, and news has become important in both the Mojave deserts and the Great Basin. ^[11] The mining industry spurred the creation of transportation systems such as the Tonopah and the tidal railway. ^[12]

Tourism

Badwater Basin Elevation Sign

In 1994, the California Desert Protection Act protected millions of acres in Death Valley and Joshua Three National Parks and Mojave National Forest. ^[13] In these parks and reserves, visitors can see unique landscapes, plants and animals. Badwater Basin, the lowest point in the United States is located in Death Valley National Park.

External link

California desert map
Visit California: Desert

We live at the bottom

Kirill Vlasov
“Cat Schrödinger” No. 9–10, 2017

The textbook of Russian history begins with events that took place a little over a thousand years ago. And what was there in the place of present-day Moscow, St. Petersburg or Samara for millions of years? The answer consists of one word: sea. And not just one, but several. A significant part of Central Russia has been covered with water more than once. In fact, we are walking on the bottom of the ancient seas.

Imagine that you have a portable time machine in your hands. It doesn't matter where she came from. Maybe it was lost by aliens during a secret visit to Earth, or Chinese corporations launched the release of such gadgets. The main thing is time travel.

You love the movie "Jurassic Park" and therefore the first thing you decide to do is go to the dinosaurs. What kind of video can be recorded and uploaded to YouTube ! In anticipation of millions of views, you put the number 150,000,000 on the scoreboard of the car. Press the red button. And...

After a moment, you hear a loud "splash". Warm salty water is poured into the nose and mouth. Having coped with your fright, you begin, swaying on the waves, to look around. There are no tropical forests. There are no dinosaurs. Everywhere the sea. “So, I made a mistake,” you think, return home and go to dry after an unexpected bath. If you try to get into the past again, it is likely that your journey will end in the same “splash”.

Real scientists do not yet have such a device, and they have to go to the distant past by exploring rocks. The most accessible of them is limestone. An ordinary white stone - you can find it anywhere: on the side of the road, at a construction site, in a parking lot, on the river bank. If you look closely at it, you can see the fossilized remains of mollusks and other sea creatures. But how did they end up on the territory of Moscow or any other city in Central Russia? The nearest sea is hundreds of kilometers from here.

We are used to the fact that the continents have clear outlines and are in their places. While we are flying from Moscow to Sochi, the Black Sea will not overflow into another lowland, and Crimea will remain a peninsula. But if, according to the precept of Doc Brown from Back to the Future, to think in four dimensions, then it turns out that the relief has changed so radically that, having looked at the globes of different geological eras, we would hardly recognize our home planet.

The seas are a temporary phenomenon. Their existence depends on two main factors. The first is the presence of a depression on the continent into which water can flow. For long periods of time, the land surface walks like a flag on a windy day: some areas rise, others fall. The second factor is the level of the World Ocean. The amount of liquid water on the planet depends on the climate and the size of the snow caps at the poles. And warming and cooling in the history of the Earth happened more than once.

How do scientists know that there was a sea in a particular place? They study sedimentary rocks: limestones, sandstones, clays, marls, dolomites, which cover almost the entire earth's crust. Roughly speaking, they drilled a well of a hundred meters, raised samples, studied the features of the rock and the remains of living creatures preserved in it. After that, we can conclude that there was a sea here: such a depth, such a salinity, such a temperature.

They deepened the well by another ten meters - they found out what happened here in an earlier era. And so on. If drilling fails (no money, the terrain is too difficult, the driller went on vacation), you can be content with natural rock outcrops - river slopes, rocks, etc.

The seas were such a widespread and rapidly changing geological phenomenon that it is impossible to consider them on the scale of a planet or even a country the size of Russia: the list will be inexhaustible.

We decided to limit ourselves to the East European platform. Against the general background, this block of continental crust can be called an island of stability. At the same time, over the past 700 million years, almost all of it managed to go under water, and some territories even several times. We took the most famous seas - those that, although they existed in the distant past, managed to make a great contribution to our geological present.

Sea of the Winter Coast

Just in case, we remind you: the Earth was formed 4.5 billion years before you acquired this number "KSH". It is known that part of the water on the planet was originally, the other was brought by ice comets. We can confidently assume that seas and land have existed for a long time: about four billion years ago, the surface of the planet cooled to a temperature at which water begins to turn from vapor into liquid. But the outlines of the oceans and continents of a very ancient Earth are known only very, very approximately. Therefore, we will omit three billion years for clarity.

At the time we were transported in this way, all the blocks of the earth's crust were connected into a huge supercontinent. The inhabitants of the current continents could easily roam from Africa to Australia and America. It is a pity that there were no inhabitants: the land was practically lifeless, although relatively developed organisms existed in the sea.

In world science, this giant continent was named Rodinia. The first hypotheses about it were made in 1970, and the name was proposed in 1990 by spouses Mark and Diana McMenamin. In this place, you can experience a surge of patriotism: American paleontologists formed the toponym Rodinia from the Russian Rodina . The name for the ocean surrounding this supercontinent is also taken from our language - Mirovia.

One of the seas included in this ocean covered the northern part of modern Central Russia. True, at that time the Russian North was in the southern hemisphere, closer to the equator.

It is difficult to say exactly when this sea appeared. But it is known that it was completely unlike modern seas, because the then Earth was radically different from the present. A day lasted less than 21 hours, a year - about 423 days. There was only 7% oxygen in the atmosphere instead of the current 23.

It was also cold. There is even the concept of "Snowball Land", according to which 630-650 million years ago our planet was an icy desert like the planet Hoth from Star Wars. And the sea, most likely, was covered with an ice shell.

However, it is still impossible to confirm or refute this statement: there is not enough data. But we know for sure that the first multicellular organisms already lived in this sea. It is believed that their assortment was not diverse - more than a hundred million years remained before the Cambrian explosion, as a result of which hundreds of thousands of species appeared on the planet.

There is very little information about these life forms: in those distant times, organisms did not yet think of acquiring skeletons or something else that does not decompose over time. Paleontologists have to be content with rare prints in the rock. They can be found on the Winter Coast of the White Sea, where sedimentary rocks formed at the bottom come to the surface.

This is how creatures resembling modern sea feathers, charnias, were discovered; analogues of crawling jellyfish are dikinsonia and worm-like spriggins. All of them are pioneers of the multicellular world, because before that, only bacteria and other unicellular organisms lived on Earth for more than a billion years.

The boundaries of the sea are difficult to specify. But what it was - that's for sure.

Almost Baltic Sea

Nothing lasts forever under the moon. About 750 million years ago, the supercontinent Rodinia began to break apart. One of the decay products was the Baltic continent. A depression formed in the northwest of this platform, where water began to flow. It became more and more: the climate on the planet was warming, the ice was melting, the polar caps almost disappeared, the ocean level was rising. This is how the sea was formed, which can be called the Baltic, although it does not at all look like a modern reservoir of the same name. It was distinguished not only by its outlines, but also by the temperature - like in a southern resort: the general warming was aggravated in this case by proximity to the equator.

Under such conditions, it was a sin not to breed any living creature. Representatives of arthropods - trilobites ruled the ball. They looked as if an avant-garde artist was commissioned to redesign a cockroach: a body consisting of segments, eyes on stalks and spikes extending in all directions. In Garrison's Fantastic Saga, Hollywood crew members find themselves on a prehistoric island and "catch them by lantern light, roast them whole, and eat them with beer."

Despite their intimidating appearance, trilobites were relatively peaceful creatures - they spent whole days rummaging in the bottom sediment, looking for goodies. At the same time, they often became prey. At that time, the first cephalopods began to appear, for which crispy arthropods were a tasty meal. According to existing data, it was trilobites who first mastered the defensive strategy of "curl up and wait."

By the end of the Silurian period - about 420 million years ago - this part of the platform began to rise, and the sea was gone.

Ural Ocean

Residents of Perm, Ufa and neighboring regions can consider themselves real submariners. For two hundred million years, the Ural Ocean existed on the planet - a huge body of water that separated the ancient continental plates - the Baltic (Fennosarmatia) and Siberia.

In the Devonian, a large coral reef stretched along the shores of the Ural Ocean. And from the Baltic side there were also island arcs with active volcanoes. They separated the shallow seas from the ocean - something like the modern Caribbean Sea, separated from the Atlantic Ocean by the Antilles.

The names of the island arcs are pleasing: Tagil (was in the Ordovician - Silurian) and Magnitogorsk (appeared in the Devonian). It is unlikely that Nizhny Tagil or Magnitogorsk is associated with someone with a warm sea and equatorial heat. But just a few hundred million years ago, these places had truly heavenly conditions, however, without mojitos, sun loungers and mulattos in bikinis.

The Ural Ocean was dominated by fish, it is no coincidence that the unofficial name of the Devonian is “the age of fish”. Evolution has experimented with the design of these animals: armored, lobe-finned, lungfish, cartilaginous - they all come from here. Some of the experiments were successful. The lobe-finned and lungfish eventually crawled onto land, becoming the ancestors of modern tetrapods. The descendants of the cartilaginous live to this day, the most obvious example is sharks.

But the armored ones were less fortunate. Mother evolution had a hypothesis: if you put a lot of armor on the fish, the fish will not be eaten. But the predators did get the hang of biting the clumsy armored ones, and by the end of the Devonian they had become extinct. It turned out that fast swimming is much more useful.

Numerous lagoons, atolls and islands are an ideal haven for planktonic organisms. There were many, many. And every Russian citizen should say a big human thank you to them. Why? Because they form oil. This Devonian reef has been studied very well: it extends from Ukhta to the Southern Urals and has been exposed by many geological wells. Geologists call it the "Domanik Formation", and such rocks are called Domanikites. These breeds are our reserve for a rainy day. Now it is not very profitable to mine: this is the so-called shale oil, which is still difficult and expensive to extract. However, the rocks cover a huge area, and at the time of high hydrocarbon prices, a detailed exploration of the region was carried out. There is no reason to worry: oil in Russia will not run out soon.

Let's return to the Ural Ocean. The Baltic and Siberia were slowly but surely moving towards each other. At the end of the Devonian, the ocean turned into a channel, in the Carboniferous period the continents converged, and the Ural Mountains rose at the meeting point.

The Moscow Sea, white stone

This sea was formed as a result of an event on a planetary scale: 433 million years ago, the continents Baltica and Laurentia collided, forming the supercontinent Laurussia (Euramerica). High mountains formed at the collision site, the platform began to sag, and the waters of the Ural Ocean poured into it - then it was still there.

At the end of the Carboniferous period, the advance of water reached its maximum. The place where Moscow is now located was the center of a fairly deep (several kilometers) sea.

We owe him the famous white stone - limestone, from which the first stone Kremlin was built under Dmitry Donskoy. If you examine a piece of this rock, you will surely find some kind of fossil or its fragment in it.

Let's reveal a little secret. The author of this text collected his first paleontological collection in a parking lot near the house, sprinkled with such limestone.

True, the main characters of that era cannot be seen with the naked eye. Limestone is based on billions of skeletons of unicellular organisms: foraminifera and radiolarians. They built their houses from calcium carbonate (the mineral calcite). The capabilities of a single foraminifera are very modest, but when tons of plankton die off every year for a million years, the result is impressive: hundreds of meters of snow-white rock. There are even coral reefs of those times in the Moscow region - one of them can be seen in the Peski quarry near Kolomna.

What happened to the sea? At the beginning of the Permian period, due to the closing of the Ural Ocean and the rise of this part of the platform, it first became shallow, and then disappeared altogether. In the next, Triassic period, there was already dry land here. The geocratic era began, when the number of areas not covered by water increased markedly.

Permian Salt Sea

In the second half of the Carboniferous, the Ural Ocean finally disappeared - the border between the future Europe and Asia became more or less land-based, and the Ural Mountains began to actively form at the site of the collision of plates.

The remnants of the ocean, sandwiched between the growing Urals and the East European Platform, have turned into a chain of very salty shallow and warm reservoirs. In the south, they connected with the Paleotethys ocean, but some of the "bridges" fell into disrepair due to the retreat of the sea and local uplifts.

The territory of the future Russia is still in the resort area - approximately at the latitude of Italy and Spain. If travel agencies had existed then, all-inclusive tours to the Ural Seas would have been in great demand regardless of the season. And cosmetologists would launch the production of creams, lotions and shampoos, similar to those that are now made from Dead Sea minerals in Israel - this is also a drying body of water with an off-scale salinity level.

Over time, the seas became shallow and disappeared, leaving behind layers of salt - sodium chloride (aka the mineral halite, aka common table salt) and potassium chloride (the mineral sylvite, tasting disgustingly bitter). The cities of Solikamsk and Sol-Iletsk are located exactly where the history of these seas ended.

Unfortunately, you can no longer swim in them. But taking a bag of Permian salt, pouring it into the bathroom, closing your eyes and imagining that you were swimming in the sea in the Urals two hundred and seventy million years ago is a real and pleasant alternative.

Triassic Caspian

Triassic is not at all maritime time for the East European Platform. The land is rising, the seas are rapidly receding. But in some places they still manage to regain lost positions. One of such places is the Caspian depression.

Sea water poured into it from the south from the Paleotethys ocean, which formed 460 million years ago in the middle of the Ordovician, bringing with it typical Triassic marine fauna like ammonites. Periodically, the area of the sea was reduced to almost zero. And if you remember the volcanic arc in the south... Tsunamis and earthquakes were commonplace in these parts. In general, life was not easy for aquatic inhabitants, the species diversity was sharply reduced.

Volga Sea

The sea is regaining lost positions. The central part of the East European Platform begins to sink - a long strait is formed connecting the warm Tethys equatorial ocean with the seas in the region of the planet's North Pole.

This strait occupied the entire territory of Central Russia. Under water was also Central and Southern Europe, with the exception of most of the territory of Ukraine, which was a large island.

The Volga region became the center of the new maritime region. No, it was still far from the appearance of the main Russian river. Basically, the Volga worked out its valley on its own, however, in its lower reaches, its channel passes through the lowlands that still remain from those seas.

It's time for marine reptiles. Numerous species of ichthyosaurs and plesiosaurs were the most dangerous and widespread predators, occupying the ecological niche of modern sharks - adjusted for the fact that both prey and hunters were an order of magnitude larger.

There are so many marine reptiles that fragments of their skeletons are found every year, even in the Moscow region. One of the latest interesting finds is the Late Cretaceous pliosaurus Luskhan itilensis , discovered in 2002 on the Volga. Outwardly, he resembled a giant dolphin with an outstretched mouth. The description of the new species was completed and recently published by an international team of paleontologists. This reptile filled the so-called Early Cretaceous gap - the lack of finds of complete skeletons dating back to the Early Cretaceous.

By the end of the Cretaceous period, the strait connecting the northern and southern seas closed, and in this place, among other things, the Moscow region appeared. It didn't go under the water anymore.

But in the Volga region, the sea has existed almost to the present day - on a geological scale, of course. Moreover, what splashed in those parts 15-10 million years ago is called the Maikop Sea. And later, a decently reduced in size, - Sarmatian.

Largest cities in the desert
City	Population
Lancaster

How can trees extract moisture in the pacific northwest

Pacific Northwest trees struggle for water while standing in it