WHAT ARE CORAL REEF?

Important ocean habitats that offer us compelling evidence about the risks posed by climate change, coral reefs are large underwater structures made up of the skeletons of colonial marine invertebrates called coral. Also referred to as "the rain forests of the seas", scientists believe that one out of every four marine species live in and around coral reefs. This makes them one of the most diverse habitats of the planet, providing for a huge portion of Earth's biodiversity.

Each individual coral is referred to as a polyp. Coral polyps live on the calcium carbonate exoskeletons of their ancestors, adding their own exoskeleton to the existing coral structure. As the centuries pass, the coral reef gradually grows, one tiny exoskeleton at a time, until they become massive features of the marine environment.

Corals are found all over the world's oceans, from the Aleutian Islands off the coast of Alaska to the warm tropical waters of the Caribbean Sea. The biggest coral reefs are found in the clear, shallow waters of the tropics and subtropics. The largest of these coral reef systems, the Great Barrier Reef in Australia, is more than 1,500 miles long (2,400 kilometers).

Scientists have explored only about 20 percent of the ocean's floor, according to the National Oceanic and Atmospheric Administration (NOAA). As such, ocean explorers continue to discover previously unknown coral reefs that have likely existed for hundreds of years.

Most of the substantial coral reefs found today are between 5,000 and 10,000 years old, according to CORAL. They are most often found in warm, clear, shallow water where there's plenty of sunlight to nurture the algae that the coral rely on for food.

Coral reefs cover less than 1 percent of the ocean floor — all the reefs combined would equal an area of about 110,000 square miles (285,000 square km), only about the size of the state of Nevada. Nonetheless, they are among the most productive and diverse ecosystems on Earth.

About 25 percent of all known marine species rely on coral reefs for food, shelter and breeding. Sometimes referred to as "the rainforests of the sea" for their biodiversity, coral reefs are the primary habitat for more than 4,000 species of fish, 700 species of coral and thousands of other plants and animals, according to CORAL.

Coral reefs are typically divided into four categories, according to CORAL: fringing reefs, barrier reefs, patch reefs and atolls. Fringing reefs are the most commonly seen reef and grow near coastlines. Barrier reefs differ from fringing reefs in that they are separated from the coastlines by deeper, wider lagoons. Patch reefs typically grow between fringing and barrier reefs on the island platform or continental shelf. The rings of coral that make up atolls create protected lagoons in the middle of the oceans, typically around islands that have sunk back down into the ocean.

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IS THERE ANY UNDERWATER VOLCANO IN THE ISLAND OF MAYOTTE?

In 2018, seismometers around the world detected mysterious rumbles emanating from a usually quiet area in the Indian Ocean between Comoros and Madagascar. At the time, researchers were astonished to find a 2,690-foot-tall underwater volcano, which is about 1.5 times the height of the One World Trade Center in New York.

The volcano was formed after the largest underwater eruption ever detected and now, scientists suspect that the volcano draws its lava from the deepest volcanic magma reservoir known to researchers.

Scientists first took notice of volcanic activity about 31 miles east of the French island of Mayotte in 2018 when seismic hums, or low-frequency earthquakes, were detected by seismometers all over the globe. However, the huge underwater volcano shocked scientists because only two seismic events had been recorded near Mayotte since 1972. Before that, a layer of 4,000-year-old pumice in a lagoon nearby is the only additional evidence of an eruption ever found. After researchers noticed that the island was moving eastward about 7.8 inches a year, they installed ocean-bottom seismometers and GPS systems to track the island's fascinating geological activity. To understand the origin of the tremors that began in 2018, the study’s lead author Nathalie Feuillet, a marine geoscientist at the French National Center for Scientific Research, along with her team embarked on a mission—dubbed MAYOBS1—aboard the French research vessel Marion Dufrense in 2019.

Credit : Smith sonian magazine

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WHY IS THE ARCTIC AND ANTARCTICA ARE DIFFERENT?

Any mention of our polar regions - the Arctic and Antarctica - perhaps conjures up images of floating icebergs and blindingly white ice sheets. Sure, that's common to them but they are also different from each other in many ways.

The Arctic: A variety of landscapes and animals

Home to the North Pole, the Arctic lies in the Northern Hemisphere, and is the northernmost region of Earth. The Arctic usually refers to the area within the Arctic Circle, and spans the Arctic Ocean and parts of Scandinavia, Russia, Canada, Greenland, and Alaska (a U.S. State). It is not always covered in ice, and comprises mountains, rivers, lakes, hills, etc. It hosts several types of land animals and vegetation.

Antarctica: Just ice cover and barely any land animal

Our planet's southernmost continent, Antarctica is where the South Pole is situated. It is almost entirely covered in ice, and hardly has any vegetation or large rivers or lakes to boast of. With barely any land animals, the largest creature to dwell on land is a wingless insect that's about half an inch. There are hardly any trees there but Antarctica has its share of lichens, moss, algae, etc.

No penguins in the Arctic

Considering videos show glistening penguins diving into the water and launching themselves back on to ice-covered land adorably, it is easy to imagine that they inhabit both the polar regions. However, these flightless birds are found only in the Southern Hemisphere, and predominantly in Antarctica. None in the Arctic!

No polar bears in Antarctica

It is called a polar bear, after all, but the name is slightly misleading. It is an animal that lives in just one polar region - the Arctic. So, there are none in Antarctica. And, the next time someone asks you if polar bears hunt penguins in the wild, you can confidently tell them that can never happen because the two never get to meet each other!

A continent without permanent residents

Only a country can have permanent residents. And since Antarctica, though a continent, has no country, it has no permanent residents. It is not home to any indigenous community either. That does not mean Antarctica has just tourists. It hosts researchers and scientists at research stations set up by many countries for experiments, especially in summer. In winter, the numbers dwindle. Hard to imagine people queuing up to be a resident in a place with punishing temperatures! On the other hand, the Arctic does host permanent residents, especially indigenous groups, since it spans several countries. In fact, it has been inhabited for thousands of years.

Summers and winters

Due to the way our planet is tilted, the poles receive less light and heat from the sun than other regions of the world. The two seasons- summer and winter - are unique. Both the polar regions have long and cold winters and short summers. During summer, the poles have daylight since the sun does not set, and in winter, it is dark since the sun does not rise. However, since the Arctic and Antarctica are in the opposite directions, when one region experiences summer, the other experiences winter, and vice-versa.

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WHERE WAS THE RARE BABY GHOST SHARK FOUND?

The newly hatched, or neonate, ghost shark was found at a depth of 1200m off the east coast of New Zealand's South Island. The rare discovery of a juvenile ghost shark off New Zealand's South Island coast will help researchers better understand the biology and ecology of this mysterious deep water fish.

Ghost sharks or chimaeras are one of the most elusive fish species in the world. They have existed for hundreds of millions of years, but not much is known about them because they usually reside at depths of up to 2,000 metres. The neonate or hatchling was found at a depth of 1,200 metres.

Ghost sharks, also known as ratfish, spook fish or rabbitfish, are not actual sharks but are closely related to sharks and rays. They are cartilaginous, meaning their bodies have stiff armour-like plates and bone-like cartilage. Adult ghost sharks have venomous spines in front of their dorsal fins. Embryos grow inside their egg capsules on the sea floor and feed off the capsules until ready to hatch (between 6 to 12 months).

Critical missing details about the species' life cycle makes monitoring chimaera populations difficult. Sixteen per cent of all ghost shark species are threatened or near threatened.

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WHAT ARE THE FUN FACTS ABOUT BELUGA WHALES?

Beluga whales are white whales that live in the Arctic. They attract a lot of attention to themselves because of their unique color and the lack of a dorsal fin. Unfortunately, they are kept in captivity more than any other whale or dolphin species. Due to the irresponsible behavior of humans they are now on the edge of extinction. Belugas are pretty and friendly white whales, and their color helps them to stay alive and protects them from danger. There are many interesting facts about the Belugas that you should know and share with your kids.

Belugas are toothed whales, but they never chew their food. They swallow their prey. Another reason why the Beluga Whale is an endangered species is the fact that they have babies only once in three years. The female Beluga always gives birth to one calf and nurses it until it’s two years of age. The period between conception and birth for Beluga whales is 15 months. So, all in all, a female Beluga can give birth to only one new offspring every three-and-a-half years. The word Beluga comes from the Russian word for white. Although, they are born dark-grey, and it takes eight years for them to turn completely white. Amazing, right? Beluga whales can swim backwards. Beluga whales, just like dolphins, have been known to save people’s’ lives by pushing them to the surface when they are drowning. A captive Beluga saved a free diver’s life in 2009 while she was competing. This fact only confirms how good animals are to us even after all the cruelty they suffer. The Belugas are threatened mostly by being captured for captivity, hunting, climate change, oil and gas development, and industrial pollution. The wild predators that hunt them are Orcas and polar bears. Beluga whales are also known as the canaries of the ocean because of their incredible capability to produce different sounds. Scientists recorded eleven types of sounds that Belugas use to communicate with each other, to identify objects or calculate distance. They have a bulbous structure in their forehead that serves as an echo box where all the sounds come from. High-pitched whistles, clicks, mews, bleats, chirps, and bell-like tones are some of the sounds recognized by scientists. The Beluga’s neck is incredibly flexible and can move up and down and left and right. Such neck flexibility helps the whale to spot their prey easily. Beluga whales living in captivity have been recorded mimicking the human voice. It’s quite amazing to hear them imitating the human voice, but on the other hand, that means they spend so much time surrounded by people in an environment that is not their natural habitat. Beluga whales are highly social creatures that like to communicate with each other and with other species as well. They live in groups called pods, and they travel together everywhere. To spot them in real life, you must visit the Arctic Ocean coastal waters where they spend most of their time. Belugas can live 70 to 80 years, though in captivity they only reach a half of that age. Beluga whales can dive up to 25 minutes non-stop, and reach depths of 2624 feet. The beluga can change the shape of its bulbous forehead, called a “melon”, by blowing air around its sinuses.

Credit : Out door revival

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