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Alkali Flies Good at Scuba Diving: Scientists Explain Why!

These Alkali flies have evolved to crawl under water so they can feed on the abundant food, alga, that grows there.

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Alkali Fly and Scuba Diving
An alkali fly creates a protective bubble in order to dive in Mono Lake, California, in this June 2017 photo released on Nov. 20, 2017. VOA

A small fly that thrives at an inhospitable California lake east of Yosemite National Park long has perplexed observers who watch as it crawls into the severely salty and alkaline water, snacks on some algae or lays some eggs, then emerges dry as a desert.

Research published on Monday finally explains the secrets of this scuba-diving insect.

These quarter-inch-long (6-mm) alkali flies possess specialized traits that let them conquer Mono Lake, scientists found. They are covered in a large quantity of fine hairs coated with special waxes that let them encapsulate themselves in a body-hugging bubble that protects them from water that would doom an ordinary insect.

“The flies have found a great gig — all the food they want with few predators. They just had to solve this one tricky problem,” said California Institute of Technology biologist Michael Dickinson, co-author of the study in the Proceedings of the National Academy of Sciences.

All insects are hairy and water repellant to some degree.

These alkali flies, whose scientific name is Ephydra hians, have magnified both traits to overcome the extreme conditions of Mono Lake, considered among the “wettest” water on Earth with a slippery, nearly oily feel. The water tends to attach to any surface due to exorbitant amounts of sodium carbonate, a chemical used in laundry detergent.

“The study provides a clear example of evolution in action,” added co-author Floris van Breugel, a former Caltech postdoctoral scholar now at the University of Washington.

“The flies have evolved to crawl under water so they can feed on the abundant food, alga, that grows there. The lake has no fish because the fish cannot live in the harsh chemicals of the lake. Thus, the flies have no major predators in the lake. Fish are why most insects would be crazy to crawl under water.”

American author Mark Twain was among those who remarked about these flies at the 12-mile-wide (19-km) Mono Lake, which is three times saltier than the Pacific Ocean. They also live at Oregon’s Lake Abert and Utah’s Great Salt Lake, also salty and alkaline.

The flies use sharp foot claws to crawl into the water from rocky outcroppings. Their hairy bodies trap a layer of air that envelops them in a protective bubble, except for the eyes to permit good underwater vision. After eating or laying eggs, they let go and float to the surface, where the bubble pops, leaving them safe and dry. (VOA)

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British-led Nekton Scientific Mission in Indian Ocean Reaches an End

The oceans' role in regulating climate and the threats they face from global warming are underestimated by many. Scientific missions are crucial in taking stock of underwater ecosystems' health

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indian ocean
A manta ray swims near the submersible during a dive off the coast of the island of St. Joseph in the Seychelles, April 8, 2019. VOA

The British-led Nekton scientific mission on Thursday completed a seven-week expedition in the Indian Ocean aimed at documenting changes beneath the waves that could affect billions of people in the surrounding region over the coming decades.

Little is known about the watery world below depths of 30 meters (yards), the limit to which a normal scuba diver can go. Operating down to 450 meters with manned submersibles and underwater drones off the island nation of the Seychelles, the scientists were the first to explore areas of great diversity where sunlight weakens and the deep ocean begins.

The oceans’ role in regulating climate and the threats they face from global warming are underestimated by many. Scientific missions are crucial in taking stock of underwater ecosystems’ health.

Principal scientist Lucy Woodall called the mission “massively successful,” saying that members believe they have found evidence near several coral islands of a so-called rariphotic zone, or “twilight zone,” located between 130 and 300 meters deep.

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Seychelles President Danny Faure, left, sits inside a submersible on the deck of vessel Ocean Zephyr, off the coast of Desroches, in the outer islands of Seychelles, April 13, 2019. VOA

“The rariphotic zone has been shown in a number of papers in the Atlantic and Caribbean but has never previously been shown in the Indian Ocean,” Woodall said, adding that months of analysis will be needed to confirm the discovery.

In this twilight zone that sunlight barely reaches, photosynthesis is no longer possible and species that cannot move toward the ocean’s surface rely on particles falling from above for sustenance. Woodall also said she was excited to see “vibrant” communities of fish during the mission.

“We’re seeing schools of small fish – that middle of the food chain – but we’re also seeing a large number of big predators – the sharks and all the other fish predators as well that are there. So this shows that protection works,” she said.

With the expedition over, the long work of analysis begins. Researchers conducted over 300 deployments, collected around 1,300 samples and 20 terabytes of data and surveyed about 30 square kilometers (11.5 sq. miles) of seabed using high-resolution multi-beam sonar equipment.

Woodall estimated her team will need up to 18 months of lab work to process and make sense of the data gathered during the expedition. The data will be used to help the Seychelles expand its policy of protecting almost a third of its national waters by 2020. The initiative is important for the country’s “blue economy,” an attempt to balance development needs with those of the environment.

On Sunday, President Danny Faure visited the Nekton team and delivered a striking speech broadcast live from deep below the ocean’s surface, making a global plea for stronger protection of the “beating blue heart of our planet.”

indian ocean
Little is known about the watery world below depths of 30 meters (yards), the limit to which a normal scuba diver can go. VOA

For Nekton mission director Oliver Steeds, Faure’s visit was a win for the ocean.

“I hope our ability to broadcast live from the ocean has helped put the oceans back on the map in the boardrooms, the corridors of power and in the classrooms,” Steeds said. “That’s where the decisions need to be made to fundamentally secure our future and the improved management and conservation of our ocean.”

He said mission members hope that nations across the Indian Ocean will have the political will to improve the management and conservation of their waters.

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“It’s been an extraordinary aquatic adventure,” Steeds said. “We’re delighted that so many people around the world have been following our progress but it only really matters if the Seychelles can continue to take a lead on the world stage as a beacon of hope for ocean conservation.”

This is the first of a half-dozen regions the mission plans to explore before the end of 2022, when scientists will present their research at a summit on the state of the Indian Ocean. (VOA)