Lake Baikal (Oldest Fresh Water Lake on Earth), Southern Siberia, Russia and Mongolia (Basin countries)

Lake Baikal is the largest (by volume) freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water. With a maximum depth of 1,642 m (5,387 ft), Baikal is the world's deepest lake. It is considered among the world's clearest lakes and is considered the world's oldest lake at 25 million years. It is the seventh-largest lake in the world by surface area. With 23,615.39 km3 (5,700 cu mi) of fresh water, it contains more water than all the North American Great Lakes combined.

Like Lake Tanganyika, Lake Baikal was formed as an ancient rift valley, having the typical long crescent shape with a surface area of 31,722 km2 (12,248 sq mi). Baikal is home to more than 1,700 species of plants and animals, two-thirds of which can be found nowhere else in the world. The lake was declared a UNESCO World Heritage Site in 1996. It is also home to Buryat tribes who reside on the eastern side of Lake Baikal, rearing goats, camels, cattle, and sheep, where the mean temperature varies from a winter minimum of −19 °C (−2 °F) to a summer maximum of 14 °C (57 °F)

We all know, Siberia is extreme cold. These temperatures are so low that Lake Baikal, situated in eastern Siberia and representing the oldest freshwater lake on Earth, and one of the largest and deepest, containing around one-fifth of the world’s freshwater, freezes over. Giant ice blocks, also called ice hummocks, form through movement of ice flow, extreme winds and cold temperatures can reach a height of 15m (50ft). When the lake freezes during the winter, an amazing phenomena takes place: large shards of transparent ice form on the surface of the lake, giving the amazing appearance of turquoise ice.

Lake Baikal is in a rift valley, created by the Baikal Rift Zone, where the Earth's crust is slowly pulling apart. At 636 km (395 mi) long and 79 km (49 mi) wide, Lake Baikal has the largest surface area of any freshwater lake in Asia, at 31,722 km2 (12,248 sq mi), and is the deepest lake in the world at 1,642 m (5,387 ft). The bottom of the lake is 1,186.5 m (3,893 ft) below sea level, but below this lies some 7 km (4.3 mi) of sediment, placing the rift floor some 8–11 km (5.0–6.8 mi) below the surface: the deepest continental rift on Earth. In geological terms, the rift is young and active it widens about 2 cm (0.79 in) per year. The fault zone is also seismically active; hot springs occur in the area and notable earthquakes happen every few years. The lake is divided into three basins: North, Central, and South, with depths about 900 m (3,000 ft), 1,600 m (5,200 ft), and 1,400 m (4,600 ft), respectively. Fault-controlled accommodation zones rising to depths about 300 m (980 ft) separate the basins. The North and Central basins are separated by Academician Ridge, while the area around the Selenga Delta and the Buguldeika Saddle separates the Central and South basins. The lake drains into the Angara tributary of the Yenisei. Notable landforms include Cape Ryty on Baikal's northwest coast.

Baikal's age is estimated at 25 million years, making it the most ancient lake in geological history. It is unique among large, high-latitude lakes, as its sediments have not been scoured by overriding continental ice sheets. Russian, U.S., and Japanese cooperative studies of deep-drilling core sediments in the 1990s provide a detailed record of climatic variation over the past 6.7 million years. Longer and deeper sediment cores are expected in the near future. Lake Baikal is the only confined freshwater lake in which direct and indirect evidence of gas hydrates exists.

The lake is completely surrounded by mountains. The Baikal Mountains on the north shore and the taiga are technically protected as a national park. It contains 27 islands; the largest, Olkhon, is 72 km (45 mi) long and is the third-largest lake-bound island in the world. The lake is fed by as many as 330 inflowing rivers. The main ones draining directly into Baikal are the Selenga River, the Barguzin River, the Upper Angara River, the Turka River, the Sarma River, and the Snezhnaya River. It is drained through a single outlet, the Angara River.

Despite its great depth, the lake's waters are well-mixed and well-oxygenated throughout the water column, compared to the stratification that occurs in such bodies of water as Lake Tanganyika and the Black Sea.

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Tatra National Park (Walk Across Clear Ice), Northern Slovakia, Poland

Tatra National Park is a National Park located in the Tatra Mountains in Tatra County, in the Lesser Poland Voivode ship Małopolska region, in central-southern Poland bordering on northern Slovakia. The Park has its headquarters in the town of Zakopane. There is a similar national park in the adjoining part of Slovakia, also called the Tatra National Park Tatranský národný park.

 

The first calls for protection of the Tatras came at the end of the 19th century. In 1925 the first efforts to create a national park, in cooperation with Slovakia, took place. Formally the park was created in 1937, on an area that belonged to the state forests authority. In 1947, a separate administrative unit, Tatra Park, was created.

In 1954, by decision of the Polish Government, Tatra National Park was created. It was established originally with an area of 215.56 km2 (83.23 sq mi), but it is currently slightly smaller, at 211.64 km2 (81.71 sq mi). Of this, 151.91 km2 (58.65 sq mi) is forest and the remainder mainly meadows. Strictly protected zones account for 115.14 km2 (44.46 sq mi), of which 61.49 km2 (23.74 sq mi) are forest ecosystems. In 1992, the Polish and Slovakian national parks in the Tatras were jointly designated a trans-boundary biosphere reserve by UNESCO, under its Man and the Biosphere Programme.

walk on water sounds like the stuff of miracles, but there’s nothing supernatural at work in the clip above. Watch as two hikers in Slovakia’s High Tatra Mountains walk across a lake that’s frozen so clearly, they look to be walking on water.

 

The National Park covers one of the two Alpine mountain ranges in Poland. The Polish Tatra range, which is a part of the Western Carpathian Mountains, is divided into two sections: the High Tatras and the Western Tatras. The landscape consists of sharp-edged peaks and hollows with numerous rock formations. The highest peak in Poland, Rysy (2,499 meters (8,199 ft) is located here.

There are around 650 caves in the park, of which the Wielka Sniezna cave system is the longest (18 kilometers (11 mi)), and the deepest (maximum depth 814 meters (2,671 ft)). Six caves of this system are open to public. 

There are several streams, the longest stream reaching 20 kilometers (12 mi). Waterfalls, such as Wodogrzmoty Mickiewicza are popular with tourists. The highest waterfall is Wielka Siklawa at 70 meters (230 ft)). The park has over 30 mountain lakes, called staw (Polish: pond). These water bodies are an important part of the High Tatra landscape. The largest lakes are: Morskie Oko with an area of 349,000 m² and maximum depth of 50.8 metres (167 ft)); and Wielki Staw with an area of 344,000 m² and maximum depth of 79.3 metres (260 ft).

 

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Flying Fish - Wonder of Nature

The Exocoetidae are a family of marine fish in the order Beloniformes of class Actinopterygii. Fish of this family are known as flying fish. About 64 species are grouped in seven to nine genera. Flying fish can make powerful, self-propelled leaps out of water into air, where their long, wing-like fins enable gliding flight for considerable distances above the water's surface. This uncommon ability is a natural defense mechanism to evade predators.


The oldest known fossil of a flying or gliding fish, Potanichthys xingyiensis, dates back to the Middle Triassic, 235–242 million years ago. However, this fossil is not related to modern flying fish, which evolved independently about 66 million years ago.

The flights of flying fish are typically around 50 meters (160 ft), though they can use updrafts at the leading edge of waves to cover distances of up to 400 m (1,300 ft)

Flying fish live in all of the oceans, particularly in tropical and warm subtropical waters. They are commonly found in the epipelagic zone. This area is the top layer of the ocean that extends 200 meters from the surface down. It is often known as the "sunlight zone" because it's where most of the visible light exists. Nearly all-primary production happens in this zone as there is enough light for photosynthesis to occur. Therefore, the vast majority of plants and animals inhabit this area and can vary from plankton to the sharks. Although the epipelagic zone is an exceptional area for variety in life, it too has its drawbacks. Due to the vast variety of organisms it holds, there is high number of prey and predation relationships. Small organisms such as the flying fish are targets for larger organisms. They especially have a hard time escaping predators and surviving until they can reproduce, resulting in them having a lower fitness. Along with relationship difficulties, abiotic factors also play a part. Harsh ocean currents make it extremely difficult for small fish to survive in this habitat. Research suggests that difficult environmental factors in the flying fish's habitat have led to the evolution of modified fins. As a result, flying fish have undergone natural selection in which species gain unique traits to better adapt to their environments. By becoming airborne, flying fish outsmart their predators and environment. This increase of speed and maneuverability is a direct advantage to flying fish, and has given them leverage when compared to other species in their environment.

Research has shown that the flying fish has undergone morphological changes throughout its history, the first of which is fully broadened neural arches. Neural arches act as insertion sites for muscles, connective tissues, and ligaments in a fish’s skeleton. Fully broadened neural arches act as more stable and sturdier sites for these connections, creating a strong link between the vertebral column and cranium. This ultimately allows a rigid and sturdy vertebral column (body) that is beneficial in flight. Having a rigid body during glided flight gives the flying fish aerodynamic advantages, increasing its speed and improving its aim. Furthermore, flying fish have developed vertebral columns and ossified caudal complexes. These features provide the majority of strength to the flying fish, allowing them to physically lift their body out of water and glide remarkable distances. These additions also reduce the flexibility of the flying fish, allowing them to perform powerful leaps without weakening midair. At the end of a glide, it folds its pectoral fins to re-enter the sea, or drops its tail into the water to push against the water to lift itself for another glide, possibly changing direction. The curved profile of the "wing" is comparable to the aerodynamic shape of a bird wing. The fish is able to increase its time in the air by flying straight into or at an angle to the direction of updrafts created by a combination of air and ocean currents.

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Pyura chilensis: The "Living Rock"

Pyura chilensis is a tunicate that somewhat resembles a mass of organs inside a rock. It is often found in dense aggregations in the intertidal and subtidal coast of Chile and Peru. It is a filter feeder that eats by sucking in seawater and filtering out microorganisms. P. chilensis has some basic characteristics common to chordates, such as the notochord and a perforated pharynx. It is born male, becomes hermaphroditic at puberty, and reproduces by tossing clouds of sperm and eggs into the surrounding water. If it is alone, it will procreate by self-fertilization.

Its blood is clear and can contain high concentrations of vanadium, which may be ten million times that found in surrounding seawater; although the source and function of this element's concentrations are unknown.

The earliest mention of the "P. chilensis" was in 1782 by Juan Ignacio Molina in his book "Saggio Sulla Storia Naturale del Chili." Molina, a Chilean abbott who was shunned from Chile along with the rest of the Jesuit missionaries, wrote this book to describe the life lived by the Chileans in the Chiloe Archipelago. He briefly describes the natives for their fondness of fishing and that the Piure was another form of sustenance for the people.

 

Inside the living rock is a mass of organs surrounded by a layer of skin and muscle. It is called a filter feeder because it inhales seawater, removes and feeds on the algae and microorganisms in the water, before exhaling the filtered water back into the sea.

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