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Wednesday, February 6, 2008

What happens as the sea level rises?


What happens as the sea level rises?

The rising sea level will cause flooding on land. This in turn, will increase the rate of erosion. Moreover, as more than 70% of the world’s population lives on coasts, the rising sea level can have disastrous results.

What happened to the Titanic?


What happened to the Titanic?

On April 10, 1912, the RMS Titanic set sail from Southampton on her maiden voyage to New York. At that time she was the largest and most luxurious ship ever built. At 11:40 PM on April 14, 1912, she struck an iceberg about 465 kms off Newfoundland, Canada. Less than three hours later, the Titanic plunged to the bottom of the sea, taking more than 1500 people with her. Only a fraction of her passengers were saved. The world was stunned to learn of the fate of the unsinkable Titanic. The remains of the Titanic were found in 1985 by Dr. Robert Ballard, an oceanographer and marine biologist with the Woods Hole Oceanographic Institution.

What happened to the oil tanker Exxon Valdez?


What happened to the oil tanker Exxon Valdez?
The Exxon Valdez, a super tanker, was wrecked off the coast of Alaska in 1989. Over 50 million litres of oil were spilt into the ocean. 36, 000 sea birds and 1000 otters were killed. Over 1600 kms of coastline was affected by the oil. Some of the oil sank to the bottom of the sea, forming a poisonous blanket over the plants and animals on the sea bed.

What happened to the Mary Rose?


What happened to the Mary Rose?

The Mary Rose was the biggest and mightiest ship of the British Navy. On the 19th July 1545, it suddenly turned over and sank, killing everyone abroad, within a few minutes. It is believed that the water in the hold, used to balance a ship, might have shifted, making the ship tilt. This would cause more water to pour in through the gun ports, and the ship would have sunk swiftly. In 1982, the remains of the ship were lifted out of the ea, and put on display. You can still see them, if you visit Portsmouth harbour in England.

What does a hurricane do?


What does a hurricane do?

When a hurricane strikes, trees can be ripped up and buildings flattened by the strong winds. Wind speeds can be more than 220 kms per hour! Torrents of rain lash and flood vast areas of land. A mountain of sea water builds up in the storm centre, and overruns coastal areas, causing widespread death and destruction.

What do sea anemones do when the tide goes out?


What do sea anemones do when the tide goes out?

When the tide goes out, sea anemone pull in their tentacles to prevent them from drying up. If you see one on the beach, don’t touch it!

Tuesday, February 5, 2008

What do fish that live in the deep-sea look like?


What do fish that live in the deep-sea look like?
The fish of the deep-sea look stranger than the normal. The world that they live in is very strange. No sunlight reaches their depths, so most of them have their own light. Food is scarce too, and so many of them have wide gaping mouth to catch whatever prey that comes near. Angler fish, lantern fish and cookie cutter shark are some deep-sea fish.

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What do explorers do in the sea?


What do explorers do in the sea?

Explorers do much more than explore under water. In fact, there are divers and explorers who do a lot of work. Surveying sites, tunneling, building bridges, laying cables and pipes are some of the work done. Besides, they inspect the submerged legs of oil rigs, and clean and mend under water structures. Divers also help find sunken ships.

What creatures live in the sea?


What creatures live in the sea?
Life began in the oceans. So it is no surprise that thousands of creatures live in it. They range from tiny fish to giant sharks, shellfish to octopuses, crustaceans like crabs and shrimps and echinoderms like sea cucumbers. Then there are reptiles such as sea snakes, amphibians that include turtles and some mammals such as seals and whales. Most animals live in the top part of the ocean where the water is warm.

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What causes the tides?


What causes the tides?
Do you know what gravity is? It is the force of attraction that pulls bodies towards the centre of the Earth. Tides are caused by the effects of gravity in Earth-Moon-Sun system.

The moon’s gravity pulls the earth’s ocean into two bulges. One bulge faces the moon and the other is on the opposite side of the Earth. As the moon travels around the earth, it drags the bulges of water with it. When a bulge hits land, water piles up and you have high tide. Between the bulges, the water level is lower and you have low tide.

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What causes dry eyes?


What causes dry eyes?

Dry eye syndrome is a common problem caused by the tear film that lubricates the eyes. Tear films are made of three layers : The outer mucus layer which helps to coat the cornea, the middle aqueous layer which provides moisture and supplies oxygen and nutrients to the cornea and the inner lipid or oily layer that seals the tear film on the eye and helps prevent evaporation.

Tears are formed in several glands around the eyes. Water is secreted by the lacrimal glands, located under the upper eyelids.

Several small glands in the eyelids secrete oil and mucus layers. With each blink, the eyelids spread the tears over the eye.

Excess tears flow into two tiny drainage ducts in the corner of the eye by the nose.

In addition to lubricating the eye, tears are also produced as a reflex response to outside stimulus such as an injury or emotion.

However, reflex tears do little to soothe a dry eye, which is why someone with watery eyes may still complain of irritation.

The most common factor for dry eye syndrome is the natural aging process. This is more common in women, who tend to have drier skin then men.

Other factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people find their eyes getting irritated when reading or working on a computer. Stopping periodically to rest and blinking keeps the eyes more comfortable.

Contact lens wearers also suffer from eye dryness because the contact lens absorbs the tear film, causing proteins to form on the surface of the lens.

Women frequently experience problems with dry eyes as they enter menopause due to hormonal changes.

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What can underwater archeologists find out from shipwrecks?


What can underwater archeologists find out from shipwrecks?
Underwater archeologists study a shipwreck to try and determine what caused it. They also try to find out how the ship was built, and how the people on board lived. Water preserves many things, and selected items from a shipwreck are carefully brought to land and examined. Cloths, jewellery, tools, instruments, personal belongings, and even the cargo all have stories to tell the archeologist!

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Monday, February 4, 2008

What are ways in which the sea is harvested for food?


What are ways in which the sea is harvested for food?
Fish from the sea, has been on the staple diet of man for ages. Fishing is one of the oldest occupations known to man. Today many efficient methods are used in fishing to catch fish that inhabit different depths in the ocean. Sonar systems help fishing boats to track shoals of fish. Trawlers haul nets across the seabed, and catch fish, that dwell at the bottom. Drift netting involves hanging a long net curtain across a stretch of sea.

In the long-lining method, fishes are caught on several long fishing lines that are laid out. Fishing boats clean and freeze the fish that is caught. This way, they are able to stay long at sea and supply large quantities to factories. Shellfish, another major seafood, is now raised in farms under the sea, as also seaweed, which is used as food in Japan and China.

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What are walruses and seals?


What are walruses and seals?
The walrus is the only species in its family, and lives in the cold northern waters. It has two long tusks that protrude from its upper jaw. The walrus uses them to punch breathing holes in the sea ice.

Seals are mammals living in the very cold parts of the Northern hemisphere. They have thick layers of fat (called blubber) or fur to stop their bodies from getting chilled. Seals can swim and dive very well indeed. When they are ashore, they waddle.

There are three main types of seal – the eared seal, ear-less seal and walruses. The eared seals, as their name suggests have ear-flaps. Sea lions, the largest eared seals of the North Pacific and Fur seals fall under this type. The ear-less seals lack ear-flaps and have short, weak forelimbs. The smallest ear-less seal lives in the Arctic and is called the Ringed seal, measuring only 1.4 metres. The largest, which is also the largest seal of any kind is the Southern Elephant seal, weighing three to four tons. Although seals spend most of their lives in the seas, they come ashore to give birth. Then they stay in colonies called rookeries, bringing up the young ones until are old enough to leave.

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What are underwater currents?


What are underwater currents?
Underwater currents are currents that are not on the surface of the ocean, but deep underwater. They are formed when cold heavy water from the polar regions sinks to the bottom of the ocean. This water creeps along the sea floor towards the equator. Where surface water is blown offshore by steady winds, this cold water rises to the surface. As the currents travel the tropics, the sun gradually warms them. Underwater currents travel many thousands of miles from their starting places in the polar oceans.

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What are trenches or troughs on the sea bed?


What are trenches or troughs on the sea bed?
Trenches or troughs are deep valleys in the sea bed. They are cracks formed when one part of the sea bed moves, and crashes against another. Some trenches are over 10 kms deep. The Marianas in the Pacific Ocean, is the deepest ocean trench.

What are trade winds? How did they get their name?


What are trade winds? How did they get their name?

The trade winds are a pattern of wind, found in bands around the Earth’s equator. They are the prevailing winds in the tropics. They blow predominantly from the northeast in the northern hemisphere, and from the southeast in the southern hemisphere.

The name came from an old nautical term in middle English, ‘to blow trade’. ‘Trade’ in middle English meant ‘path’ or track. These winds helped the traders to navigate ships around the world.

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