Category Sea/Ocean

WHAT IS A SHINGLE BEACH?

When stone, pebbles and small rocks are deposited along the coast, they create a porous layer that is not as tightly packed together as sand is. These are shingle beaches. Common to New Zealand, Japan and the United Kingdom, shingle beaches support little vegetation and mostly have lichen-covered rocks.

The term shingle beach refers to a beach along any body of water that is made up of stones, pebbles, and other small rocks. These materials, also known as shingles, may vary in size from 2 to 200 millimeters and can also be mixed with other sediments, like sand or silt. Shingle beaches are primarily characterized by a steep profile, which means the area further inland sits at a higher elevation than the section of the beach found along the water. These beaches are located along a number of geological formations, including spits, barrier islands, and pocket beaches. Since the stones and pebbles that make up these beaches do not fit tightly together, they create a rather porous environment. These large pores prevent the beach from retaining any significant amount of water, although they also prevent evaporation in the soil below. Many shingle beaches can be found in New Zealand, Japan, and the United Kingdom.

Geologists have linked the formation of many shingle beaches to areas around the world that were subjected to glaciation during the Pleistocene era. These areas tend to be located at higher latitudes, and glaciers brought with them rocks and pebbles that were deposited on the shorelines. Sometimes the rocks and pebbles on shingle beaches are deposited by rivers that empty into the ocean. Additionally, shingle beaches may be formed from intense wave activity that erodes larger pieces of rock located further inland. Over time, continued wave activity carries these large pieces of sediment onto the shores, depositing the biggest pieces further from the water and at higher elevations. The composition of these beaches works to decrease the strength of the tide as it moves back out to the ocean.

Credit: World Atlas

Picture Credit : Google

WHAT IS A COAST?

Land that runs along a sea or ocean is called a coast. The edge of the land where it meets the water is called the coastline. Coasts can be wide swathes of soft, sandy beaches, narrow, rocky stretches or sheer cliff faces. Coastlines are given shape by waves, currents and tides. They are ever changing and form an important and unique environment.

If you’ve ever been to the beach, you’ve been on a coast. The coast is the land along a sea. The boundary of a coast, where land meets water, is called the coastline.

Waves, tides, and currents help create coastlines. When waves crash onto shore, they wear away at, or erode, the land. But they also leave behind little parts of the sea, such as shells, sand dollars, seaweeds, and hermit crabs. Sometimes these objects end up as more permanent parts of the coastline.

Coastal changes can take hundreds of years. The way coasts are formed depends a lot on what kind of material is in the land and water. The harder the material in the land, the harder it is to erode. Coastlines of granite, a hard rock, stay pretty stable for centuries. Sugarloaf Mountain, on the coast of Rio de Janeiro, Brazil, is made mostly of granite and quartz. It has been a landmark for centuries.

Tides, the rise and fall of the ocean, affect where sediment and other objects are deposited on the coast. The water slowly rises up over the shore and then slowly falls back again, leaving material behind. In places with a large tidal range (the area between high tide and low tide,) waves deposit material such as shells and hermit crabs farther inland. Areas with a low tidal range have smaller waves that leave material closer to shore.

Credit:  National Geographic Society

Picture Credit : Google

WHAT CAUSES TIDES?

Water level on the surface of the oceans rises and falls. These are called tides. Tides are a result of gravitational forces of the Moon and the Sun as well as the centrifugal forces of Earth’s spin. The total amount of water does not change; it just rises at one place while receding at the other.

High tides and low tides are caused by the moon. The moon’s gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.

As the Earth rotates, your region of Earth passes through both of these bulges each day. When you’re in one of the bulges, you experience a high tide. When you’re not in one of the bulges, you experience a low tide. This cycle of two high tides and two low tides occurs most days on most of the coastlines of the world.

Tides are really all about gravity, and when we’re talking about the daily tides, it’s the moon’s gravity that’s causing them.

As Earth rotates, the moon’s gravity pulls on different parts of our planet. Even though the moon only has about 1/100th the mass of Earth, since it’s so close to us, it has enough gravity to move things around.

When the moon’s gravity pulls on the water in the oceans, however, someone’s bound to notice. Water has a much easier time moving around, and the water wants to bulge in the direction of the moon. This is called the tidal force.

Because of the tidal force, the water on the side of the moon always wants to bulge out toward the moon. This bulge is what we call a high tide. As your part of the Earth rotates into this bulge of water, you might experience a high tide.

Credit: SciJinks

Picture Credit : Google 

Which is the world’s first omnivorous shark?

Bonnethead sharks were thought to be solely carnivorous, but according to University of California researchers, they’re omnivorous they can eat both animals and plants.

Bonnetheads, one of the smallest members of the hammerhead family, are abundant in the waters of the Americas, where they usually feed on crab, shrimp, snails and bony fish. Its plant of choice is seagrass. Researchers fed five bonnetheads on a three-week diet of seagrass and squid. All the sharks put on weight over the course of the study. Tests on the sharks showed that they successfully digested the seagrass with enzymes that broke down components of the plants. A possible reason for the sharks’ omnivorous lifestyle is potentially avoiding conflict with other species such as bull sharks or nurse sharks for food.

It is one of the most radical rebrandings in history: contrary to their bloodthirsty image, some sharks are not irrepressible meat eaters, but are happy to munch on vegetation too. According to US researchers, one of the most common sharks in the world, a relative of the hammerhead which patrols the shores of the Americas, is the first variety of shark to be outed as a bona fide omnivore. The bonnethead shark is abundant in the shallow waters of the eastern Pacific, the Western Atlantic, and the Gulf of Mexico, where they feed on crab, shrimp, snails and bony fish. Though small by shark standards, adult females – the larger of the sexes – can still reach an impressive five feet long. Scientists at the University of California in Irvine, and Florida International University in Miami, decided to investigate the sharks’ dietary habits after reading reports of the fish chomping on seagrass, the flowering marine plant that forms subsea meadows in some coastal waters.

To see whether the sharks are truly flexitarian, the scientists retrieved sea grass from Florida Bay and hauled it back to the lab where they re-planted it. As the seagrass took root, the researchers added sodium bicarbonate powder made with a specific carbon isotope to the water. This was taken up by the seagrass, giving it a distinctive chemical signature. The researchers next caught five bonnethead sharks and brought them back to the lab. Once the fish had settled in, they were fed on a three week diet of the seagrass and squid. All of the fish put on weight over the course of the study. The scientists then ran a series of tests on the sharks. These showed that the fish successfully digested the seagrass with enzymes that broke down components of the plants, such as starch and cellulose. Lacking the kind of teeth best suited for mastication, the fish may rely on strong stomach acids to weaken the plants’ cells so the enzymes can have their digestive effects. In all, more than half of the organic material locked up in the seagrass was digested by the sharks, putting them on a par with young green sea turtles.

Credit : The Guardian

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WHAT DID EARLY ANIMALS LOOK LIKE?

By around 500 million years ago, bacteria in the oceans had evolved into the earliest fish. These strange creatures had no jaws; they had funnel-like Sucking mouths.

The first animals – including the common ancestor of all animals today – evolved in the sea over half a billion years ago. We have no direct evidence of what they were like.

But by studying animals today, we can work out features they must have shared – small size, soft bodies, and a tendency to stay very still or creep slowly across the ocean floor.

The creatures had bodies built from multiple cells with specialised roles, like organisms before them. Now, those cells could also form sheets called epithelia, allowing structures to develop. Along with increased genetic complexity, this set the scene for big changes.

Earth’s environment was in flux during the Cambrian period, and the Ediacaran period that came before it. Sea levels rose, and chemicals washed into the ocean. In the underwater world, evolution got to work. New creatures emerged that could move further than ever before – and change their environment by burrowing and building. Soon, the new species were living in every habitat across the length and breadth of the ocean.

Credit: Natural History

Picture credit: Google

Can seaweed clean your teeth?

NEWCASTLE University scientists claim that an enzyme isolated from marine bacterium Bacillus licheniformis cuts through plaque on teeth and cleans hard-to-reach areas. Dr Nicholas Jakubovics of the university’s School of Dental Sciences said: “Plaque is made up of bacteria which join together to colonize an area in a bid to push out any potential competitors. Traditional toothpastes work by scrubbing off the plaque containing the bacteria. But that’s not always effective which is why people who religiously clean their teeth can still develop cavities.” When bacterial cells die, the DNA inside leaks out and creates a biofilm that sticks to teeth, protecting the bacteria from brushing, chemicals or even antibiotics. Bacillus licheniformis, found on the surface of seaweed, releases an enzyme which breaks up the biofilm and strips away harmful bacteria.

Researcher Prof. Burgess said: “The zyme breaks up and removes the bacteria esent in plaque and importantly, prevents build-up of plaque too. If we can contain it with’n toothpaste we would be creating a product which could prevent tooth decay. The enzyme also has huge potential in he ping keep clean medical implants such as artificial hips and speech valves which also suffer from biofilm infection.”

Picture Credit : Google