WHAT IS A BAYMOUTH BAR?

When the movement of waves deposits gravel and sand in a manner that prevents access to a bay, it builds up a baymouth bar. The existence of the bar creates a shallow lake known as a lagoon that is separated from the sea by a beach.

A baymouth bar is a depositional feature as a result of longshore drift. It is a spit that completely closes access to a bay, thus sealing it off from the main body of water. These bars usually consist of accumulated gravel and sand carried by the current of longshore drift and deposited at a less turbulent part of the current. Thus, they most commonly occur across artificial bay and river entrances due to the loss of kinetic energy in the current after wave refraction.

In most cases, a Sand Bypass System is built to prevent these bars forming across the entrance of man-made seaway's, eliminating the danger posed to commercial and recreational boat owners passing through.

credit: en-academic.com

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

Picture Credit : Google 

What jellyfish looks like a plastic bag?

First discovered in the 1960s, Deepstaria enigmatica — named for underwater explorer Jacques Cousteau's submersible Deepstar 4000, and the jellyfish's mysteriousness - has only made rare appearances since.  It is looking like a plastic bag. In November 2017, Deepstaria was spotted off the coast of San Benedicto Island, around 3,195 feet deep down in the Pacific Ocean.

Resembling a plastic bag, it has a large, thin bell and no tentacles. Since most jellyfish use tentacles to catch their prey, Deepstaria has to rely on another method. Since its bell can open up to a metre across, Deepstaria uses it to catch upward-moving prey. closing around the prey like a bag.

Deepstaria enigmatica have been observed during jelly-falls. This happens when a jellyfish carcass falls through the water column to the ocean floor. A Deepstaria enigmatica jelly fall was first observed in the lower portion of the oxygen minimum zone of the ocean. It was observed as shrimp and crabs were scavenging its carcass.

These jelly falls are advantageous to the ocean floor, causing a source of organic enrichment, similar to a whale fall; as carcasses decay away from light and the more oxygen-rich environments of the upper ocean, the animal decays far slower, providing a longer-lasting source of nutrients. The carcasses lead to a restoration of degraded mineral content in the water column. The contribution of these jelly falls is underestimated. The Deepstaria enigmatica fall shows an increase in oxygen availability and organic matter, benefitting the ecosystems found at the bottom of the ocean.

The Deepstaria jellyfish, unlike many jellyfish, lacks tentacles of any kind, which other species of jellyfish commonly use to entrap and consume prey. Instead, Deepstaria trap prey inside their bell, where they are consumed. This method also provides for isopods, who may live inside the jellyfish's bell in a symbiotic relationship

In the 1960s Jacques Cousteau, a French explorer, unexpectedly found the Deepstaria jellyfish in a deep-sea exploration mission. He was exploring the deep sea near Southwest Baker Island in a submarine called the Deepstar 4000, which became the inspiration for the name of this jellyfish. The Deepstaria jellyfish has been found in the Gulf of Mexico, Antarctic, and the Pacific Ocean. In all of these locations, the jellyfish was found 3,000 ft (910 m) below sea level.

Credit : Wikipedia 

Picture Credit : Google 

Do Seahorse males give birth?

When it comes to seahorses, it is the male that gets pregnant and gives birth to baby seahorses. The female swims to the surface of the water with the interested male in tow. It transfers its orange eggs into the pouch of the male which then adds its sperm and seals the opening. The growing babies will remain in their dad's pouch till they develop. Once they are born the babies are on their own.

After completing an elaborate courtship dance that may go on for hours or days, the female seahorse transfers her mature eggs into the male’s brood pouch, where they are fertilized. At the end of a gestation period usually lasting from two to four weeks, the pregnant male’s abdominal area begins to undulate rhythmically, and strong muscular contractions eject from a few dozen to as many as 1,000 fully formed baby seahorses into the surrounding water. After that, the offspring must fend for themselves. Large litters are necessary because only about 0.5 percent will survive to adulthood.

Many, if not all, of the 47 known seahorse species—14 of which were identified only in the 21st century—are in decline worldwide.

Because seahorses generally live in shallow, near-coastal waters, human activities including development, pollution, fisheries, and traditional medicine have reduced their numbers. At the same time, their universal appeal has worked against them; until recently, wild seahorses were often captured for the aquarium trade. The delicate creatures tend to fare poorly in aquaria, however. In recent years, captive-bred seahorses have shown promise as hardier tank-dwellers than their wild relatives.

Credit : National Ocean Service

Picture Credit : Google

What is seashore?



 



 



 



The seashore is where the land meets the sea. Sometimes seashores are rocky and have high cliffs. Other seashores are gently sloping, sandy beaches. In some places seashores are made from lots of smooth stones.



 



 



 





 



 



These waves are crashing against cliffs.



This seashore is made from hard rock and has steep cliffs. When waves smash against the cliffs, they slowly wear them away or crack the rock. Sometimes the cliff breaks apart and large pieces of rock fall down into the sea. Under the water, the fallen rocks are tumbled together by the waves and break up into tiny pieces.



 



 





 



 



A sandy beach slopes down into the sea.



When land made from soft rocks meets the sea, the seashore is flat and sandy. Sand is made up of billions of tiny pieces of rock and broken shells.



 



 





 



 



Shingle beaches are covered with stones.



Shingle beaches are made up of small pebbles that have been smoothed by the waves. Shingle seashores are hard places for animals and plants to live because the sea moves the stones around. Most wildlife lives high up on the shore out of reach of the waves.