Why does the sea sometimes glow at night? What you didn't know about the Sea of ​​Azov. Interesting facts Interesting information about the Sea of ​​Azov

The ancient Greeks did not consider it a sea, but called it Lake Meotia.

The Sea of ​​Azov is a shallow, flat body of water with low coastal slopes. The water in it is muddy, and the shores are bare, low, clayey-sandy. In summer, the temperature of the upper layers of water often warms up to 28-30 degrees. At the same time, winds blow on its coast and above the surface all year round. Sometimes they are so strong that they push water onto the shore. Then the sea level in the coastal zone rises by several meters.

According to one theory, the Sea of ​​Azov arose 7,500 years ago as a result of a strong rise in the level of the Black Sea. And currently, its water level is steadily falling. If the situation does not change, sooner or later this beautiful sea will disappear altogether.

Azov has many names. It is called the Sea of ​​Shellfish. The ancient Slavs called it the Surozsky or Blue Sea. And the modern name comes from the Arabic phrase Bahr el-Azov or “dark blue sea.” But very often its waters acquire a greenish-yellow hue due to mixed sand. At the same time, there is a lot of plankton in the sea. Because of this, at night its surface glows. Here are some more interesting facts about this amazing body of water on the planet:

1. This is the shallowest sea in the world. Its maximum depth is only 13.5 meters. On average, the depths of Azov do not exceed 7 meters.
2. The ancient Greeks did not consider it a sea, but called it Lake Meotia. The Romans agreed with them, calling Azov the Meotian swamp.
3. The most distant sea from the ocean. Its waters are separated from the Atlantic by 4 seas: the Black, Marmara, Aegean and Mediterranean. This is the most continental sea on the planet.
4. Its water is 3 times fresher than in other seas. It can quench your thirst. And all because of the abundant influx of river water into the Azov basin. In addition, water exchange with the Black Sea is difficult near the Sea of ​​Azov. Due to its low salinity, it freezes in winter.
5. The most fishy sea in the world. Due to its low salinity, the Sea of ​​Azov is rich in fish. There are even river species here. Its small size turned the reservoir into a kind of fish nursery.
6. The main minerals are oil and combustible gas. The Sea of ​​Azov is rich in minerals hidden both at its bottom and under it. Gas fields line its entire coastline. The most promising oil and gas bearing horizons are the Lower Cretaceous deposits. And the most oil-bearing ones are Maikop.
7. The Amazons lived on its banks. The state of Meotida was located on the coast of the Sea of ​​Azov. According to ancient Greek legends, beautiful women warriors or Amazons lived in the territory washed by the Black and Azov Seas. Almost all ancient writers write about them. The Amazons were first mentioned in the Iliad.

At night, near our shore there are both phyto- and zooplankton - everything mixes in shallow water. And most plankters are able to glow in the dark. This is one of their most joyful properties – for us. Chemically, the glow reaction of marine organisms is exactly the same as that of the firefly beetles that we admire on warm summer nights on the shore. Substance – luciferin (light carrier - Greek) oxidized by oxygen under the action of an enzyme luciferase . Most chemical reactions produce heat, but this one produces one quantum of green light.

From July to the end of September. But the best time is from early August to early September - the first weeks of summer-autumn plankton development.

Already approaching the dark water, we see that the weak surf is shaking pieces of greenish light on the sand - feel them with your hands - they are slippery, they melt on your fingers. These waves washed the ctenophores to the shore, they were already smashed on the sand, but they continue to glow. Shake them off your hands - and the light remains on your palms - even smaller pieces of the delicate bodies of sea creatures stuck and remained on your skin. If we walk along the edge of the surf, we will find small, constantly glowing dots on the sand - we will pick them up and try to examine them. These are amphipods, sea fleas - but already dead, they don’t jump like the ones we chased during the day. These crustaceans have already begun to be eaten, decomposed, by bacteria, which always glow - in the same way that rotten eggs glow. Why do planktonic organisms glow? Let's wait until night and answer this question ourselves. The darker the night, the better - the flashes of living light in the sea will become more noticeable. And, of course, the sea must be calm - otherwise we will not see anything. In general, the night should be quiet, dark and warm. There are many of these on our shore - from the beginning and in the night forest. Don’t be scared – admire it, this is also life. Amphipods have a lot of microscopic spines on their shell - we've already seen them - these spines will allow you to attach a glowing badge to your T-shirt - just press the crustacean to the fabric.

We will enter the dark transparent water from a familiar beach - by touch. On a summer night, the sea is warmer than the air above it, you can swim without feeling the water - they usually say it’s like fresh milk! - but night is night - and it’s probably worth reminding you once again about caution - don’t swim to a place where you can’t stand on the bottom.

Let's step slowly, without splashing, from the shore and look at our feet. And your legs glow! These are tireless plankters - mobile algae, crustaceans - colliding with our skin and flashing with emerald light, there are so many of them that the bodies of people moving in the water become emerald. When there is really a lot of plankton, you can see a striking sight - a floating luminous person. He dives - and shines brightly under water, and leaves a sparkling trail behind him.

It’s rare, but sometimes you’re lucky enough to see the games of dolphins glowing with green fire! And if you go out to sea on a boat at such a time, the oars seem to be on fire - and with each stroke, tongues of green flame break off them and remain behind, circling and writhing.

Such an even, strong glow, in which individual flashes are not visible, is caused by planktonic dinoflagellates - they are most abundant in warm water. Diatoms cannot glow. Our every movement in the water causes radiance and flashes. The glow is many small flashes of microalgae merging into a single glow - there are so many of them. And individual bright green lights are flashes of irritated planktonic crustaceans. Sprinkle water - green sparks will fly into the air - you, along with the drops, threw a lot of tiny crustaceans into the air. This is probably the only – and wonderful – way to see, without a microscope, life in every drop of sea water.

If something bright and large lights up in the water near you, it is a ctenophore - the largest luminous animal in the Black Sea. You can try scooping it up with your palms - look at its shine.

Not only planktonic microorganisms glow, but also many bottom microorganisms: try to dive onto a rocky bottom and rub any smooth surface - it will glow; pick up a stone from the bottom, rub it - it will still glow when you emerge and lift it above the water. If there have been no waves over the sandy bottom for a long time and no people have swam, even on the surface of the loose soil a film of microlife that can glow is formed - then, walking along such a bottom, you will leave emerald traces.

We have already realized that plankters do not glow all the time, but when irritated - by hitting an obstacle or strong water movement. Such signals for a copepod or dinophyte algae are a sign of a possible approach of a predator, or even a collision with it. The flash should scare away the aggressor. How can such a small spark scare someone? But compare the sizes! People are usually frightened by the unexpectedly lit up comb jelly - and yet it is only the size of an apple. For a small planktivorous fish - sprat, silverside - a flash of green fire from the crustacean Oytona can be a reason to flee. And an outbreak of dinophyte algae, in turn, can scare away a copepod or worm larva. So the glow of plankton, which delights us so much on summer nights, is the active protection of weak plankton from voracious planktivores.

There are rare cases of constant glow of planktonic algae - during a powerful bloom of noctiluca, or other dinophyte algae. The density of algae during such a powerful development of phytoplankton - millions of cells per liter of water - is such that individual collisions, individual flashes of light, simply merge into a constant glow.

Some marine organisms have light signals that are not intended to scare away, but, on the contrary, to attract someone - to eat this someone, or, if it is an individual of the opposite sex, to mate with it.

Deep-sea anglerfish hang luminous organs in front of their open mouths, and the prey fish, swimming towards the light, ends up in the teeth of the anglerfish. In the Black Sea, from the family of anglerfish, one is occasionally found - the European anglerfish, or monkfish - a fish of a completely extraordinary appearance, but this species, although it has a fishing rod with bait suspended above its wide mouth, it does not glow. It rarely appears near our coast - sometimes it ends up in trawl nets.

Monkfish - alas, does not glow.

It is natural that there are no luminous angler fish in the Black Sea. For successful hunting, they need complete darkness - these are fish of the deep. In our sea, deeper than 150-200 meters, the water does not have the oxygen necessary for breathing, but there is poisonous hydrogen sulfide; fish cannot live there.

A remarkable light appears in the sea at the places and times when certain species of planktonic polychaete worms mate. Our platineris and glycera, which we have just examined, unfortunately do not glow. But the common Atlantic Nereis once a year puts on a fantastic light show in the waters of the Gulf Stream. On the night of the first summer new moon, the entire population of the island of Bermuda gathers on the bridge across the narrow straits that divide this island, located on the very rapids of the Gulf Stream. The only mating night of the year for sea worms, a local Bermuda festival - and I was lucky enough to be there at that time. Standing on a bridge over one of the island channels and peering into the black water, you finally notice the first, glowing with a bright, white-green light, wriggling worm as long as a finger, thick as a match. It’s not for nothing that the Gulf Stream is called a river in the ocean - the current speed is 4 km/h, the speed at which you and I walk. And now the current brings new Nereis, after half an hour - the water turns into a boiling, shining, white-green stream - the worms swim, spewing out luminous clouds of eggs and semen, which mix before our eyes, these are fountains of light, this is - literally - a celebration of the birth of a new life accompanied by fireworks! You go down to the shore, catch a Nereis, and your palm becomes covered with a luminous liquid...

The glow of Nereis, in addition to attracting mating partners, also plays a deterrent role: in the sea there are many invertebrates and fish that can eat both worms and their eggs, but the bright light of the mass of Nereis, their eggs and seeds will undoubtedly scare them away.

This story, of course, is not Black Sea, it is simply about one of the wonders of marine life, most of which await you ahead. And the Black Sea is a very good sea for the first steps on this path.

By the way, the story of the Gulf Stream glowing from worms ended with the general laughter of all the biologists who were then working at the Bermuda Biological Station. That evening the whole company from the biological station went to watch the Nereis mating. But one Japanese did not go - he said that he had already seen a similar phenomenon. We returned late at night, joyful, animated, found and pushed aside the sleepy Japanese biologist, began to tell him... He stopped us and silently led us with him - it turned out that he was going to the toilet. Fresh water is in very short supply in Bermuda, and to flush toilets, water is pumped into the cisterns directly from the sea. The Japanese turned off the light in the toilet, pressed the flush... Streams of glowing, sparkling water poured into the toilet, illuminating the cramped room.

The Black Sea is a body of contrasts, stories and legends. Like any huge water resource, it has hundreds of secrets. The Black Sea at the junction with the Azov Sea is especially interesting - there you can appreciate the beauty of their differences and scale. If the Azov Sea is more like a huge lake with shallow depth, then the Black Sea is a real abyss. An ominous, beautiful and breathtaking abyss.

Paleontologists believe that in the Black Sea region, since the formation of the Earth, there have been salty bodies of water: the Pontic and then the Meotic seas. In other periods, the area dried up, and fresh springs and lakes formed here. The sea acquired its modern boundaries, depth and type of water a little more than 8,000 years ago. The reason for these changes was the devastating earthquake that formed the Bosporus Strait. Due to it, the Mediterranean Sea connected with a water source nearby and began to give water to the “newborn”.

The area of ​​the Black Sea is greater than 422 square kilometers. Its length is 580 km from north to south, while the maximum depth is 2210 m. The reservoir connects southern Europe and Asia Minor.

Facts, mysteries and wonders of the Black Sea

You can tell more than one long story or legend about the Black Sea. Here are just 15 small but interesting facts about him:

1. According to ancient legend, Jason set out on a journey across the Black Sea with the Argonauts in search of the Golden Fleece. Their path ran through land and water to Colchis.
2. The first mentions of a sea source are in documents of the 5th century BC; they are associated with the expansion of the lands of ancient civilization.

1. The Black Sea alone has many names that are still used by different peoples and countries. Some names have disappeared over time. The ancient Greeks, for example, called it the Inhospitable Sea, or Pont Aksinsky. It was renamed Hospitable because the Greeks developed the shores and found them attractive for winemaking, agriculture, and trade. In ancient Greek the name began to sound like Pont Euxine. Much later, during Ancient Rus', the sea was called Scythian, somewhat less often - Russian. Historical documents found in European countries and Asia also mention other names. So, it corresponds to: Temarun, Holy Sea, Ocean, Akhshaena, Blue Sea, Cimmerian, Tauride. There is no exact information about why it became known as Black. Some historians believe that it is called this way because of the color of the designation. Previously, the North was designated black, and this sea referred to it. The second theory indicates that the sea received its name due to the large amount of hydrogen sulfide in the water. If any metal got to the bottom, it turned black. However, thanks to this same hydrogen sulfide, sunken ships remain at the bottom several times longer than in the waters of other seas.
2. Only 2,500 species of animals live in the waters, perhaps due to the peculiarities of their composition. Usually 2-3 times more representatives live in the seas. In the Mediterranean - 9000.
3. Hydrogen sulfide is no less important in a small number of inhabitants. Its concentration at a depth of more than 200 meters is so great that not a single living creature is able to survive there.
4. In August, at night, the sea waters begin to glow due to the migration of plankton populations, which phosphoresce.

1. Unlike many seas and oceans, the name Black has different inscriptions and pronunciations in different countries.
2. Due to its young age, the Black Sea may increase in size. The same goes for the mountains located around it. This can also be seen in the ancient cities of Crimea, which go under water for tens of meters. Oceanologists believe that every 100 years the size of the reservoir increases by an average of 20 cm.
3. Sea dragon- the most predatory and deadly fish living in the Black Sea waters. Its thorns contain poison that can kill an adult.
4. The seal is a creature of cold climates, but it finds refuge in the waters of the Black Sea.
5. The main biomass is represented jellyfish– only 10% is allocated to other creatures.
6. The Black Sea has one large peninsula - Crimea - and only 10 islands. When compared with the Caribbean or Mediterranean, this amount is ten times less.
7. The Black Sea is a source of oil and gas. But they lie so deep that no country has yet reached production.
8. Far from the shores, the sea surface is cut by huge whirlpools, the wave length of which reaches 400 km.
9. In winter, the sea waters freeze only partially; there is a glaciated area near Odessa. Byzantine documents indicate that in 401 and 762 BC, shackles of ice completely covered the sea surface.

The Black Sea is home to thousands of resorts and sanatoriums on its shores, which are visited by millions of tourists every year. However, few people think about how much power and danger lurks in these hospitable waters.

Glowing plankton is an amazing sight. This microscopic organism is capable of transforming an entire sea into a shining starry sky, transporting the observer to a fantastic world of magic.

Plankton

Plankton is a general name for many diverse organisms that primarily live in well-lit layers of water. They are not able to resist the force of the current, so often groups of them are carried to the shores.

Any (including luminous) plankton is food for the remaining, larger inhabitants of the reservoir. It is a mass of algae and animals that are very small in size, with the exception of jellyfish and ctenophores. Many of them move independently, so during periods of calm, plankton can move away from the shore and cruise around the reservoir.

As mentioned above, the upper layers of the sea or ocean are richest in plankton, but certain species (for example, bacteria and zooplankton) inhabit the water column to the maximum depths possible for life.

What types of plankton glow?

Not all species have the ability to bioluminescence. In particular, large jellyfish and diatoms are deprived of it.

Luminescent plankton is mainly represented by single-celled plants - dinoflagellates. By the end of summer, their numbers reach their peak in warm weather conditions, so during this period you can observe especially intense illumination off the seashore.

If the water shines with separate green flashes, then you can be sure that these are planktonic crustaceans. In addition to them, ctenophores are prone to bioluminescence. Their light is dimmer and spreads across the body with azure tints when colliding with an obstacle.

Sometimes a rather rare occurrence occurs when glowing plankton in the Black Sea it shines for a long time without interruption. At such moments, dinophyte algae bloom, and the density of their cells per liter of liquid is so high that individual flashes merge into a bright and constant illumination of the surface.

Why do plankton glow in the sea?

Plankton emit light through chemical processes called bioluminescence. Upon thorough study, it was revealed that this is nothing more than in response to irritation.

At times it may seem that the action occurs spontaneously, but this is not true. Even the movement of water itself serves as an irritant; the force of friction has a mechanical effect on the animal. It causes an electrical impulse rushing towards the cell, as a result of which a vacuole filled with elementary particles generates energy followed by chemical reaction, resulting in a surface glow of the body. With additional exposure, bioluminescence increases.

Speaking more in simple language, we can say that luminous plankton will shine even brighter when colliding with any obstacle or other irritant. For example, if you put your hand into the very cluster of organisms or throw a small stone into its center, the result will be a very bright flash that can momentarily blind the observer.

Overall, this is a very beautiful sight, because when objects fall into water filled with plankton, blue or green neon circles radiate from the place where they hit. Watching this effect is very relaxing, but you should not overuse throws into the water.

Where to see

Glowing plankton is found in the Maldives and Crimea (Black Sea). It can also be seen in Thailand, but, judging by the reviews, not often. Many tourists complained that they even visited paid beaches for this spectacle, but were often left with nothing.

If you have scuba diving equipment, it is very cool to observe plankton at depth. It is comparable to being under a falling star and literally takes your breath away. However, this should only be done with a small concentration of organisms. This is due to the release of poisonous toxins by some types of plankton that are dangerous to human health.

Therefore, it is still safer to observe the glow from the shore. It is especially not recommended to let children into the water at such moments, since a dose of toxins that would be trifling for adults can cause intoxication in a growing organism.

The Black and Azov Seas wash the southern shores of Russia and every year they literally become a place of pilgrimage for vacationers from all over the country and even from near and far abroad. But how much is known about these seas to those who like to relax on their sunny beaches? This article contains some interesting facts about the Black and Azov Seas and their inhabitants.

Interesting facts about the Sea of ​​Azov

The Sea of ​​Azov is the deepest in the world. Its average depth is 8 meters, which is not much greater than the depth of an ordinary pond or lake, the maximum is about 13 meters. However, in 2007, during an unprecedented storm, as many as 4 dry cargo ships managed to sink here.
Lake Baikal is approximately 94 times larger than the Sea of ​​Azov!

Azov is also the warmest of all seas. Due to the shallow depth and very hot weather in the summer in the south, it can warm up to 30 degrees Celsius in just a couple of days.
Doctors say that the sand that covers the beaches and the bottom of the Azov Sea can have a healing effect on the human body. This is probably due to the proximity of healing mud lakes and volcanoes.

If you swim in the Sea of ​​Azov on a starless summer night, especially at the end of August, you will notice that the water in it glows. This glow comes from certain species of plankton living along the coastline; their bodies contain phosphorus, which, in fact, glows in the dark.

Before the name Azov was finally assigned to this sea, it changed many names. The Slavs called it Sourozh or Blue, the Greeks - Meotida (which means “nurse”), the Arabs - Bahr el Azuf, the Genoese and Venetian sailors - Mare Fane, and the Romans disparagingly called Azov Palus Meotis - Meotian swamp.

Despite its small size, the Sea of ​​Azov is one of the richest in the world in terms of biodiversity. A wide variety of fish live here, making this water surface very attractive place for fishing lovers. And for the incredible number of mollusks, the sea even received a second, unofficial name - Mollusk.

Unlike most seas, the Azov Sea freezes in cold winters. This happens because the water in it is less salty than in many other seas and freezes at a temperature of about 0.5-0.7 degrees below zero.

In the Sea of ​​Azov there are never low tides or high tides.

Interesting facts about the Black Sea

There are about 2,500 species of different living creatures in the Black Sea. For the sea, this is a relatively small number: for example, the Mediterranean is home to more than 9,000 species. However, in the Black Sea waters at a depth of more than 150-200 meters, there is no life of any kind, since the waters at the very bottom are saturated with hydrogen sulfide. Only a few types of bacteria can live there.

At the end of summer, the Black Sea, like the Sea of ​​Azov, glows at night. The reason for this is the planktonic algae nightlight, which contains phosphorus.

Initially, the ancient Greeks called the Black Sea Pont Aksinsky, which means Inhospitable. This name was probably due to navigational difficulties and frequent storms. Later, when Greek colonies had already appeared on the Black Sea coast, the sea received a different name - Pont Euxine, which means Hospitable.

There is only one species of shark in the Black Sea - the katran. This is a small shark, rarely growing more than a meter in length. Naturally, it does not attack people; the only thing that makes it dangerous is the poisonous, spiny fins on its back.

The most poisonous of the Black Sea fish is the sea dragon. Its dorsal fin and gill covers contain a very strong poison that is dangerous to humans.

The Black Sea even has its own holiday, which, in fact, is called International Black Sea Day. It is celebrated annually on October 31st.
It is interesting that in ancient times the Arabs called the Black Sea the White Sea.

IN last time The Black Sea froze completely in the 17th century.

The rapana mollusk was brought to the Black Sea from the Sea of ​​Japan with Far Eastern ships. This mollusk, despite its external harmlessness, is capable of completely destroying some types of mussels and other mollusks, since it is a predator. This is what happened in the Black Sea. Their natural enemies - starfish - could reduce the population of rapanas, but they are not found here.

As you can see, the Black and Azov seas are full of unusual animals, beneficial properties, secrets and legends. Therefore, it’s time to pack your suitcase and go to the southern resorts to explore it all in more detail!