Tag Archives: nature

Why Planes Need to Avoid Fine Volcanic Ash

Aircraft avoid any airspace that has volcanic ash in it for a simple reason: the ash can wreck the function of propeller or jet aircraft, because it is so fine [less than 2mm in diameter, and some as fine as 6 microns] that it will invade the spaces between rotating machinery and jam it – the silica melts at about 1,100C and fuses on to the turbine blades and nozzle guide vanes (another part of the turbine assembly), which in modern aircraft operate at 1,400C.

That, in turn, can be catastrophic – as the crew of two aircraft, including a British Airways Boeing 747, discovered in 1982 when they flew through an ash cloud from the Galunggung volcano in Indonesia. On both planes, all four engines stopped; they dived from 36,000ft (11km) to 12,000ft before they could restart them and make emergency landings.
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The Icelandic plume has been thrown to between 6km and 11km into the atmosphere – exactly the height that aircraft would be flying.

Passengers on the BA flight that hit the cloud in 1982 said the engines looked unusually bright: soon after all four flamed out. “I don’t believe it – all four engines have failed!” said the flight engineer. The crew were prepared to ditch, and the captain told the passengers: “Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them under control. I trust you are not in too much distress.”

Luckily, three of the engines could be restarted. The plane landed safely, and nobody was injured.

Critter Cam: Sea Lion versus Octopus

Octopus vs. Sea Lion – First Ever Video

Sea lions fitted with GPS trackers and a National Geographic Crittercam are taking scientists on amazing journeys to previously unknown marine ‘hot spots.’ These areas are important not only for providing the sea lions’ food, but also for maintaining fish populations.

The Crittercams were deployed at Dangerous Reef in Spencer Gulf, a rocky island the size of a football field, and home to the biggest Australian sea lion colony.
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Dr. Page says, “One important discovery is that the sea lions always feed on the sea floor” and they don’t eat open ocean fish, known as pelagic. “This is critical information because the marine parks are being set up to protect sea floor habitats,” a move that the scientists can now confirm will protect critical sea lion resources.

In one of the more spectacular pieces of Crittercam video so far, we can see this female working hard to handle a challenging prey item – a large octopus. Too big to swallow in one gulp, she drags it to the surface where she can breathe while she works at breaking it down into bite-size pieces.

Spring Tulips

photo of red and yellow tulips by John Hunter

Photo of red and yellow tulips in my yard. This is by far the most tulips that have flowered. The last several years I think there were 3-5 flowers. This year there are 20 in the front yard.

Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.
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they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Albatross Chicks Fed Plastic Ocean Pollution by Parents

photo of dead Albatross chick

See more photographs of remains of albatross chicks on the Midway Atoll, a tiny stretch of sand and coral near the middle of the North Pacific.

The nesting babies are fed bellies-full of plastic by their parents, who soar out over the vast polluted ocean collecting what looks to them like food to bring back to their young. On this diet of human trash, every year tens of thousands of albatross chicks die on Midway from starvation, toxicity, and choking.

To document this phenomenon as faithfully as possible, none of the plastic in any of these photographs was moved, placed, manipulated, arranged, or altered in any way. These images depict the untouched stomach contents of baby birds in one of the world’s most remote marine sanctuaries, more than 2000 miles from the nearest continent.

Friday Fun: Bird Mimics Other Birds and More

The lyre bird, not only mimics the calls of other birds, buy also man made noises such as cameras, saws and chainsaws, in an attempt to impress potential mates. David Attenborough narrates the above clip.

Guadalupe Mountains National Park: Ladybug City

Ladybugs crawling on rocks in Guadalupe Mountains National Park

photo of ladybugs covering the bark of a tree near the Guadalupe Peak, by John Hunter, Creative Commons Attribution.

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At Guadalupe Peak, the highest point in Texas at 8,749 feet in Guadalupe Mountains National Park I found a huge city of ladybugs. They covered the bark of many bushes and trees and crawled over rocks (as seen in the photos). They were everywhere. It seems odd to me that they would have such a huge concentration since it would seem like food would then be a problem, but there they were.

Continue reading →

Honeybees Warn Others of Risks

Honeybees warn of risky flowers

They trained honeybees to visit two artificial flowers containing the same amount and concentration of food. They left one flower untouched, making it a “safe” food source for the bees.

On the other flower, they placed the bodies of two dead bees, so they were visible to arriving insects, but would not interfere with their foraging. They then recorded whether and how the bees performed a waggle dance on their return to other members of the hive colony.

On average, bees returning from safe flowers performed 20 to 30 times more waggle runs that bees returning from dangerous flowers.

That shows that the bees recognise that certain flowers carry a higher risk of being killed or eaten by predators, such as crab spiders or other spider species that ambush visiting bees.

Bear Defeats Combination Bear Lock

Bear-Proof Can Is Pop-Top Picnic for a Crafty Thief

Yellow-Yellow, a 125-pound bear named for two yellow ear tags that help wildlife officials keep tabs on her, has managed to systematically decipher a complex locking system that confounds even some campers.
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“She’s quite talented,” said Jamie Hogan, owner of BearVault, based in San Diego. “I’m an engineer, and if one genius bear can do it, sooner or later there might be two genius bears. We’re trying to work on a new design that we can hopefully test on her.”

His company and New York’s Department of Environmental Conservation have cautioned campers in the Adirondacks against using the BearVault because of its vulnerability here. There have been no reports of the BearVault being regularly broken into anywhere else in the country.

So last year Mr. Hogan introduced the 450, a two-pound cylinder costing about $60, and a larger version, the 500, each with a second tab. On them, a camper must press in one tab, turn the lid partway, then press the second tab to remove the lid. “We thought, ‘O.K., well, one bump didn’t work so maybe two bumps will thwart her,'” he said.

But Yellow-Yellow figured that lid out, too.

Getting Kids to Rediscover the Great Outdoors

photo of lantern tree

Back to nature: Getting kids to rediscover the great outdoors

Childhood is supposed to look like this, according to many children’s health experts and an increasing number of landscape architects and urban planners. Wading in puddles or streams, building hideouts, climbing trees or exploring a “secret” outdoor spot develops the senses, stimulates the imagination and releases pent-up energy. Studies show that “a dose of nature” can be more effective than a dose of medication in reducing the symptoms of attention deficit disorder (see sidebar). Obesity and depression are alleviated, too.

“Nature stimulates that sense of wonder,” says UW Health psychologist Katie Watermolen. “When kids are outside, they are less anxious, more creative, more relaxed. All that leads to improved mental health.”
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A 2007 report released by the American Academy of Pediatrics says free and unstructured play is healthy and, in fact, essential for helping children reach important social, emotional and cognitive developmental milestones as well as helping them manage stress and become resilient.

Great stuff. I agree. See photos of my hikes in national parks. The 2007 report doesn’t believe in free and open science though – outdated closed science journal rules apply. When will people lean – both that science should be open and nature is good for kids? Progress isn’t helped when the scientists working for public schools restrict their research by allowing journals to hide their research from the public.

Photo by John Hunter at Forest Glen Preserve, Illinois – Creative Commons Attribution.