Category Sea/Ocean

WHAT IS THE DIFFERENCE BETWEEN SEA TURTLES AND LAND TURTLES?

The names sea turtle and land turtle are a little bit confused among most of general people, as the scientific means are somewhat different. Therefore, a proper understanding would be beneficial for anyone. Scientifically, the term turtle refers to the marine testudines. Freshwater testudines are known as terrapins, and the land living or the terrestrial testudines are scientifically referred as tortoises. However, according to the commonly used terms or names, all these three types are known as turtles with the adjective of the respective environment. Interestingly, certain types are still known as terrapins or tortoises. Therefore, solving this controversy would take a few steps, and this article would be one such step as it discusses the characteristics and performs a comparison between land and sea turtles. In other words, this article is a brief comparison between turtles and tortoises.

Sea Turtle

Sea turtles or turtles are one of the earliest to live on the Earth, and the fossil evidences suggest that they had inhabited the world at least 210 million years ago. The fascinating thing about them is they have been able to survive until today with a wide diversity that accounts more than 210 extant species including land, freshwater, and sea turtles. However, there are only seven sea turtle species currently inhabit the oceans of the world. They are remarkably well adapted to the oceanic lifestyle with developed flippers do locomotion. Turtles are blessed with the longest lifespan of all the animals on the Earth, which is more than 80 years according to certain references but some state that it could go as high as 180 years. Sea turtles are distributed in all the oceans of the world except in the Arctic and Antarctic regions. They come to the surface for breathing and sometimes for navigation. The most fascinating characteristic of sea turtles is that they come back to the same beach that they were born for eggs laying.

Land Turtle

Land turtles, aka tortoises, are land dwelling reptiles belong to Class: Reptilia in general and to the Oder: Testudines in particular. There are more than 45 extant species currently, but the number is more likely to be increased. Tortoises being testudines, they have a shield covering their body known as the shell. The shell comprises of two types of structures known as the carapace (the top portion) and the plastron (the underside), and these two are interconnected by a bridge. In addition, tortoise has both the endoskeleton and the exoskeleton (shell). Land turtles come in different sizes depending on the species. They are diurnal animals more often than not, but some are crepuscular. However, their active time depends mostly on the ambient temperature of the environment. The majority of the tortoises demonstrate the sexual dimorphism, but the differences between the two sexes vary among species. For example, some species have larger male compared to the female, but certain other species have it in the other way around. Upon breeding, the female tortoise digs nesting burrows and lays one to thirty eggs in a burrow. Then, the eggs incubate in the ground for 60 to 120 days depending on the species. Usually, tortoises are herbivores, but some are omnivores as they feed on worms and insects.

Credit :  Difference between.com

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HOW DID THE SPECTACLED CAIMAN GET ITS NAME?

The spectacled caiman (Caiman crocodilius) gets its name from the bony ridge that lies between its eyes that gives it the appearance of wearing a pair of glasses. The spectacled caiman belongs to the family Alligatoridae along with many other species of crocodile and alligator. Unlike the other species in its family, the caiman seems to have benefited from the removal and displacement of the larger crocodilian species. The spectacled caiman is considered Least Concern by the IUCN and enjoys a range that stretches from southern Mexico all the way to Brazil (as pictured below). They were introduced in Puerto Rico, Cuba, and the United States. The spectacled caiman is considered to be highly adaptable to the rivers and lowland wetlands that it inhabits. These attributes have led to it being one of the most widespread species within its taxonomic family.

The yellow and black spots that distinguish juveniles from adults is a well-known feature of this species and can be observed in the photos below. This species can grow to a mere 8ft compared to its larger cousin, the black Caiman that can grow up to 19 feet in length. The males tend to be larger than the females. Adult spectacled caimans are a dull olive green and the yellow and black spots that juveniles have fade as they age. This species of crocodile endures the extremes of its ecosystem using a form of hibernation called estivation.  Estivation is the ability to hibernate through the dry and low prey summer season in its habitat. When its environment becomes too harsh the spectacled caiman can burrow in the mud and protect itself from overheating.

The caiman is considered a keystone species in its environment because it enjoys the status of a top predator, and its removal can lead to harsh consequences lower in the food chain. As juveniles, spectacled caimans consume aquatic insects, small fish, crustaceans, and mollusks. As adults, they eat just about anything they can catch, including mammals, birds, fish, and other reptiles. They have a total number of 72 to 78 teeth. Males and females become sexually mature around 4-7 years of age but it has been shown that sexual maturity can be based on size and size can be based on competition. In areas of high competition, it may take a particular individual more or less than 4-7 years to completely mature.

Some of the main threats for this species are being hunted for their skin and being killed solely because they frighten local populations. Although they are not currently threatened, their conservation as a keystone species is important because they keep many of their prey species in check in delicate river and lowland areas. In the areas that they have been introduced, specifically Cuba, they have put native populations of other species of crocodile at risk because they can outcompete local species. Also, since the 1950’s when hunting of the several larger species of crocodiles was occurring, the caiman has proliferated because of a lack of competition from larger species with healthier populations. The caiman is a species that in some areas of its range needs to be controlled and maintained in ecosystems where it occurs naturally.

Credit : Stedwards. education

Picture Credit : Google 

WHAT DO CROCODILES AND ALLIGATORS EAT?

Baby crocs and alligators will catch insects and spiders to eat. As they grow, fish and birds form a larger part of their diet. When fully grown, they will prey on anything that comes their way: fish and birds, as well as small and large mammals.

Wild crocodiles are advantageous carnivores, capable of eating whatever prey that happens to stumble upon them. They have even been known to eat humans from time to time as well, but more on that later!

The larger the crocodile, the larger the prey. According to a study done by the Northern Australia Environmental Resources Hub, saltwater crocodiles have been known to eat large wildebeest and even other crocodiles!

A captive crocodile in a zoo is will often eat:

Mice
Rats
Raw chicken
Raw beef
Fish

Whether it be in captivity or in the wild, crocodiles are highly opportunistic eaters, and they are also comfortable eating dead animals or carcasses.

How Much Does a Crocodile Eat?

A crocodile eats on average 2-5 pounds of meat per day, or roughly 5% of its body weight per week. It depends on the overall size of the crocodile and the amount of food that is readily available to them, however. A croc with a great deal of prey nearby may eat much more than 2 pounds of meat a day!

According to the Journal of Herpetology, an adolescent crocodile needs to eat at least 4% of its body weight weekly depending on its size, while a captive croc needs to eat at least four times that amount.

Crocodiles usually require less food than warm-blooded mammals, but this doesn’t mean they don’t feast or gorge themselves on food. They are one of the few predators incapable of tearing their food into smaller pieces- they have to eat their meals whole.

Crocodiles are also not picky eaters in the least. They will eat most anything that crosses their path or can’t outswim them. Depending on the location of the species and the current weather, crocodiles will eat a variety of different things.

For example, crocs will eat much more fish and aquatic creatures during wet and rainy months, while they will need to eat more land mammals during drier months. No matter what, if a crocodile can fit the unsuspecting prey in its jaws, it will do its best to eat it!

Credit :  A-Z Animals 

Picture Credit : Google 

 

IS THERE UNDISCOVERED LIFE IN OCEANS?

So much of our oceans is still unexplored and remains a mystery. In fact, it is safe to presume we know more about the surface of Mars than about Earth’s seafloors! But whatever  we little know of life in ocean depths is intriguing, fascinating, and incredible. The deep oceans are low on sunlight and plants but high on pressure, and yet, several creatures call this space home. Here’s a glimpse of how they have adapted to life in unforgiving conditions.

Colours that help

Since they dwell in open waters without plants or rocks to hide under to safeguard themselves from predators, many creatures benefit from disguise. Some of them are red. rendering them difficult to spot since red light does not penetrate those depths. Some others are transparent, again tough to spot. Many others are bioluminescent, a good tool to confuse predators.

Heard of sea snow?

Since ocean depths hardly have any plant, finding “live meal” is a tough task. Apparently, the duration between two live meals can be even up to three weeks for a marine creature! That’s where marine snow or sea snow comes into play. When no live meal is available, the next best thing to turn to is the dead. Organic particles from the surface waters – disintegrated bodies of animals and plants, mingling with fecal matter-drift down in what is known as “marine snow”.

What is chemosynthesis?

At the cracks between oceanic plates are hydrothermal vents – these are the hot springs on the ocean floor. These vents send out chemical compounds such as hydrogen sulphide. These chemical compounds are used for preparing food – much like sunlight is used in photosynthesis. This process used by microorganisms such as bacteria to create food (such as glucose), is called chemosynthesis.

Though humans still don’t have a complete understanding of ocean depths, we’re definitely leaving our mark there- and, sadly, not in a good way. With global warming, over-fishing, and pollution, we’re changing the composition of the oceans they are acidifying, and hosting crustaceans with microplastics, as far deep as the Mariana Trench, the deepest location on Earth.

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WHY IS DENMARK’S BUBBLING REEF UNIQUE?

A dip in the waters in the Hirsholm islets off the northern shores of Denmark is like diving into a giant aquarium. Amidst the dazzling colours of its vibrant marine life, tiny bubbles from the seabed soar to the surface like clear blobs. The unique phenomenon is caused by the presence of methane gas. The gas was probably formed due to the microbial decomposition of plants deposited thousands of years ago under the sea. As the gas seeped up through funnels in the floor, chemical reaction with underwater microbes hardened the sand particles into sandstone structures. Water currents washed away the surrounding loose sand, leaving behind solid stone columns, arches and slabs, which became thriving hubs of plant and animal life. The methane constantly bubbles out through vents in these columns, resembling air bubbles in a fish tank. The site is an important centre of marine biology.

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WHY IS THE FORESTS OF THE MARINE WORLD UNDER THREAT?

A type of algae, kelp is crucial for thriving ecosystems the world over. However, kelp forests are shrinking. But, why? Let’s find out

Most types of seaweed or marine algae grow along the coasts in shallow waters, where they can attach themselves to rocks, shells, or the sea floor. A root-like part called holdfast anchors them firmly and prevents them being washed away by strong waves or currents. A soft, flexible stem-like frond with outgrowths similar to leaves emerges from the holdfast. Though they carry out photosynthesis, algae are not plants as they don’t have true roots, stems, leaves, or flowers. Marine algae can be green, brown, or red in colour. Red algae are delicate and feathery and prefer warm tropical seas. Small green algae are found everywhere in shallow waters. Brown algae called giant kelp grow in cool waters at depths ranging from 15 to 40 mt.

Extraordinary ecosystem

A kelp forest is one of the most valuable and productive: ecosystems on Earth. Kelp forests are found all over the world-the west coasts of North and South America, the southern tip of Africa and Australia, and off islands near Antarctica. In North America, kelp forests are found on the Pacific Coast from Alaska to California. A forest of kelp is home to a variety of creatures. They live and forage for food among its broad blades. The kelp provides shelter not only from predators. but also from storms. Mammals and birds that thrive in kelp forests include seals, sea lions, whales, sea otters, gulls, terms, egrets, and herons. Sea otters have an especially beneficial bond with kelp. Mother otters wrap their babies in kelp to keep them from drifting away while they go hunting. Adult otters also find the dense kelp canopies a secure place to snooze. The otters return the favour by eating sea urchins that dine on kelp. Kelp forests can shoot up in no time, growing up to 30 cm a day. Some species attain heights of over 45 mt!

Kelp farming is a big part of the billion-dollar global seaweed-farming industry. Kelp renders sea water less acidic. This enables kelp farmers to raise shellfish, which require low acidity. Kelp and mussels are grown on floating ropes, which also support baskets of scallops and oysters. One kelp farm can produce 40 metric tonnes of kelp and a million shellfish per hectare per year! As with other species of seaweed, kelp is used in many products,) including shampoos and toothpastes, as well as a wide range of foods such as salad dressings, puddings, cakes, dairy products, and ice cream. It is also employed in pharmaceuticals and in the manufacture of fireproof and waterproof textiles.

Urchin attack

The waters off the coast of northern California are home to lush forests of bull kelp. Since 2013, the population of purple sea urchins that feast on the kelp, has exploded, destroying almost 90 % of the kelp forest. Sea stars prey on purple urchins and keep their numbers in check. However, a mysterious disease killed off huge numbers of sea stars, leaving sea urchins to thrive. Sea snails (called red abalone) and red sea urchins, both of which are raised for meat and feed on bull kelp, died from starvation. Commercial red sea urchin and red abalone fisheries located on America’s northwestern coast have closed down as a result.

Fact file

• Kelp forests are the ocean’s lungs just as trees are the Earth’s lungs. They absorb carbon dioxide and give out oxygen.

• Warming seas along the Australian coast have wiped out huge swathes of kelp forest.

•Extremely hot weather is harmful to kelp forests. Strong storms can wipe out large areas by uprooting the plants from the sea floor.

• There are 18 species of edible kelp, including kombu widely used in Japanese cuisine.

•Kelp is rich in calcium and Vitamin K.

Picture Credit : Google