WHERE IS THE HAWKSBILL TURTLE FOUND?

The hawksbill gets its name because its mouth resembles the sharp beak of a hawk. The turtle, which has a beautifully coloured and patterned shell, lives among the coral reefs of the Pacific, Indian and Atlantic Oceans. It can grow to about 1.14 m, more than half the length of a full-size bed, and weigh almost 70 kg.

Hawksbill turtles often nest in small numbers, and usually on remote beaches. The largest populations of hawksbills are found in the west Atlantic (Caribbean), Indian, and Indo-Pacific Oceans.

The largest nesting populations of hawksbill turtles occur in Australia and Solomon Islands. Approximately 2,000 hawksbills nest annually on the northwest coast of Australia and 6,000 to 8,000 nest annually in the vicinity of the Great Barrier Reef. The largest rookery for hawksbill turtles in the South Pacific Ocean is in the Arnavon Islands of the Solomon Islands, where approximately 2,000 hawksbill nest each year. Arnavon hawksbills have been heavily exploited for their shell for centuries, but two decades of conservation and monitoring efforts are showing encouraging signs of recovery. Around 2,000 hawksbills nest each year in Indonesia and 1,000 in the Republic of Seychelles. 

In the Atlantic, the greatest number of hawksbill nests are laid in Mexico, Cuba, and Barbados, but nesting occurs throughout the Insular Caribbean. The most significant nesting within the United States occurs in Puerto Rico and the U.S. Virgin Islands. Each year, about 500 to 1,000 hawksbill nests are laid on Mona Island, Puerto Rico and another 100 to 150 nests on Buck Island Reef National Monument off St. Croix. In the continental United States, nesting is rare and is restricted primarily to the southeast coast of Florida and the Florida Keys. 

In the U.S. Pacific, hawksbills nest primarily in Hawaii where 10 to 25 females nest annually on beaches along the south coast of the island of Hawaii and the east coast of the island of Molokai. This population may constitute one of the smallest hawksbill nesting populations in the world, but is the largest in the Central North Pacific Ocean. In the Eastern Pacific, approximately 700 females nest annually from Mexico to Peru.

Credit : National oceanic and atmospheric administration

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HOW ANTARCTIC FIN WHALE CAME BACK FROM EXTINCTION?

Often, within the pages of wildlife conservation stories lies that one spark, idea, or action that spawns dramatic positive changes. Here's one such story on how one decision has resulted in a huge impact, practically bringing back a key species from the brink of extinction.

The recent filming of southern fin whales in Antarctic waters thrilled scientists, researchers, and conservationsists  no end.  And, why not? It's a deeply encouraging sign that not only have these marine mammals returned to their historic feeding grounds but their numbers have increased too, albeit gradually. The species was earlier reduced to less than 2% of its original population, thanks to the usual suspect-unsustainable hunting for decades. And then came the whaling ban towards the last quarter of the 20th Century, positively impacting the course of the animal's fate over decades. Slowly but surely fin whales have rebounded; slowly because fin whales give birth to only one calf at a time.

Over the last few years, researchers have recorded a hundred groups of these whales, including large ones comprising up to 150 animals. "Using data from their surveys, the authors estimate that there could be almost 8,000 fin whales in the Antarctic area." Listed as "vulnerable" by the International Union for Conservation of Nature, fin whales have a tremendous impact on the environment. In fact, they are called "ecosystem engineers" because after consuming iron-rich krill, they excrete nutrients that help the "growth of tiny phytoplankton, the foundation of the marine food web". In addition, the increasing number of this marine mammal - the world's second largest animal-is also an indicator of the ocean's good health.

While other threats cannot be ruled out for these ocean giants, the "increasing numbers of southern fin whales is an encouraging sign that conservation measures can work".

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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