Even More Trivia: nature

Showing posts with label nature. Show all posts

Friday, 12 February 2016

Giant Crystal Caves

Today's trivia is all about the a mine in North Mexico known as the Naica Mina.

This mine was first opened in 1794, though only officially exploited in 1900. The mine is of interest commercially for its deposits of lead, zinc and silver, among other minerals which are still actively being extracted.

Before mining could start the mine has to be drained of water. The water level normally resides at a depth of 110m below sea level. This needed to be drained to a depth of 850m below sea level. A complex pumping system had to be developed to be able to do this and can extract 22,000 gallons of water per minute when turned on.

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In the year 2000 another system of three caves were discovered which contain some rather impressive crystals. We'll be talking specifically about the "Giant Crystal Cave", located at 290m below sea level. Some of these selenite crystals are immense. The cave's largest crystal found to date is 12m (39 ft) in length, 4m (13 ft) in diameter and weights 55 tons.

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Formation of the Crystals

The Naica mine lies on an ancient fault above an underground magma chamber below the cave.

The magma heats the ground water which was saturated with sulfide ions. Meanwhile cool oxygenated surface water comes into contact with the mineral saturated heated water, but the two did not mix due to the difference in their densities. The oxygen slowly diffused into the heated water and oxidized the sulfides into sulfates.

This creates an environment where hydrated sulfate gypsum can crystallize at an extremely slow rate of over the course of at least 500,000 years forming the enormous crystals found today.

The key to this process is the slow diffusion of oxygen from the cool, low density surface water into the hot, high density ground water.

Conditions in the Cave

Exploring the cave is particularly hazardous for humans. The ambient temperature is 58C (136F), and the humidity is close to 100%.

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This represents two significant risks to humans:

Heat Exhaustion Unprotected from the heat, the human body cannot regulate its temperature quick enough in those sorts of temperatures. You would be sweating profusely if you found yourself stuck down there would ultimately pass out from the lack of water and sodium in your body.

Breathing The air in this sort of temperature would be incredibly difficult. It would be likely that the in insides of your lungs would be cooler than the outside temperature. The humidity would start to condense inside your lungs leaving only a short time window for exploration.

A lot of infrastructure has been put in place to support exploration of the caves.

Before you can enter the caves you reach a staging area which is at a comfortable 41C. This staging area hosts all the support equipment required to venture into the actual crystal caves. This includes freezers to store the cooling suits, video monitoring equipment and paramedics on standby in the event of a medical emergency.

Camera equipment has to be allowed to come up to temperature before it can be used in the caves, otherwise it would risk fogging up.

Refrigeration Suits

To explore the caves, researchers had to develop specific suits to help protect the wearers from the conditions in the caves.

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Ptolomea Suit

The initial suit design created by Giovanni Badinno consisted of multiple layers:

Insulated layer: protects the wearer from direct skin contact with the icy cooling layer
Cooling layer: Ice tube covered layer to protect the entire body from the` excessive temperature.
Outer layer: Rugged overalls to reduce heat transfer by radiation and protect from jagged environment

This suit allows the wearer an hour of effective research time in the caves however it comes at the drawback of being heavy and restricts mobility for the wearer.

View of the inner cooling layer of the suit, total weight 22kg

Lightweight Suit

The researchers were able to optimise the design trading off some exploration time for a more mobile suit design. Instead of complete body coverage in cooling ice tubes, they opted for a cooling layer which just covered the torso in frozen gel packs. This allows more mobility for the arms and legs with an exploration time of around 30 minutes.

The lighter suit system weighs 8kg in total

Breathing System

Breathing in the cave is difficult without breathing apparatus. For this they developed a backpack based system. Replaceable frozen metal bottles are stored in the backpack with a fan which blows warm air over the bottles. This is then fed into a face mask which allows the wearer access to cool air to breath.

Fitted facemask

Inside the backpack of the air cooling system, frozen metal bottles act as the cool source

Future of the cave

Once the mining operations in the cave end, it is expected that they will turn off the water pumping system, allowing the thermal water level to rise and once again fill the the entire cave system. The facilities to support exploration of the crystal caves and the caves themselves would become inaccessible and will resume their slow growing process.

References:

Friday, 11 December 2015

Sleep in Ants

Today’s trivia is about Ants, and in particular their sleep patterns.

Firstly we can confirm that Ants do sleep and exhibit demonstrable sleep behaviours.

We will dig further into the subterranean life of these invertebrates to understand more about their sleep patterns.

There is only a handful of research papers on sleep in Ants. (Bees are considerably more researched). The paper we are most interested in is this one:

Polyphasic Wake-Sleep Episodes in the Fire Ant Solenopsis Invicta

The research paper covers a particular species, Solenopsis Invicta famous for its stinging ability.

Sleep in Insects

Sleep in insects is particularly interesting because insects have quite different physiology. Another problem is how to actually determine sleep in insects:

Homeostasis: The balance between sleep and awake periods, sleep deprived flies are more sleepy during the day

Alertness: Insects which are sleeping are slow to respond to external stimulus

Circadian Rhythm: Insects that live above ground are likely to have periods of increased activity and periods of rest in line with a daily cycle, insects which live underground are generally polyphasic with no discernable circadian rhythm

Getting an Ant colony

How does one acquire an ant colony to study sleep patterns? Ant hives are constructed entirely underground with only thermal venting sections placed above ground.

Drip flotation method

In fire ants, the drip floatation method takes advantage of a flood-survival adaptation of the ants to accomplish this task. The key principle is that ants are so small and light that they are naturally buoyant. They also have a waxy coating which helps repel water and allows the entire colony to stay afloat when they cling together. Combined with their ability to self organise they can effectively float an entire colony on water.

Dig up an ant colony and place it in a large bucket
After 24 hours the ants will reestablish the structure of the colony with brood in chambers and tunnels to the surface excavated
Talc powder is used on the sides of the container to prevent the ants climbing the sides.
Water is dripped slowly into the bucket
After 4-8 hours the water level rises slowly enough the the colony has gathered on the surface, brood and queens included
Eventually the colony will form a raft, floating on the surface which can then be transferred to an artificial nest.

Sleep Patterns

Key observation about the sleep behavior as anticipated is that because they are a subterranean species they are not affected by day/night cycles, rather sleep patterns are determined by activity in the hive.

Workers

Average 253 sleeps per day
Each sleep about 1 minute
Total 4.8 hours of sleeping a day

Workers tend to sleep in one of three locations, the chamber floor, ceiling or side of chamber. Those that sleep on the chamber floor were most likely to be woken by other workers passing by. Seemingly the best place to sleep was the side of the chamber.

Queens

Average of 92 sleeps per day
Each sleep about 6 minutes
Total 9.6 hours of sleeping per day

Queens exhibited two observable sleep patterns:

Dozing: antenna extended, stationary, likely to be woken by contact from a worker.

Deep sleep: antenna tucked in close, stationary, unresponsive to external stimulus. Prone to random antenna movement during deep sleep.

Delightfully the queens would synchronise their sleep patterns so that they all would sleep at the same time, and woke up at the same time. They did this by huddling together when they slept, like hounds. When one started to stir the others would wake up as well.

Conclusion

The net result of this experiment found that at any given time there was on average 80% of the work force available to work on grooming, feeding or excavating sand. Queens in this species can live for 6 years, workers only one month.

The hive is always busy (hyper active) at attending to the needs of the Queens and buffering them from environmental effects which might be detrimental. This allows the queens to maintain a high reproductive efficiency and extend their longevity.

References

More about Fire Ants

Video of a sleeping Bee

Friday, 14 August 2015

Curious Adaptations of Gastropods

Today's trivia looks at some of the most interesting adaptations in the Gastropod family.

As a species, Gastropoda are incredibly diverse. Only insects represent a more diverse species. This trivia hopes to cover more adaptations that some species of Gastropod have evolved to allow them to live where they do.

The familiar garden snail has evolved all the adaptations needed to live on land.

The following are some examples of the wonderful variation found in the Gastropod family.

Raft Building

This first example is known as the common purple snail Janthina janthina. This snail floats on the surface of the water by building a 'raft'. The raft is made up of air bubbles trapped in a thin layer of chitin. This allows the snail to stay afloat in the sea and feed on its preferred food, jelly fish.

A common purple snail washed ashore. Note the raft remains intact.

Common purple snail floating in water.

Net-Hunting

Perhaps even stranger is a species of Cone snail called Conus tulipa which uses its very modified mouth parts to find and envelope small fish that stay too close to it. Once captured, the snail draws in the catch and slowly digests it.

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Harpoons

All members of the Conus family are predators, and another fascinating adaptation is a combination of harpoons and neurotoxin venoms. The mouthparts of the Cone snail are again highly specialised. The harpoon is held in a long tentacle like extension of its mouth which it uses to catch and paralyse small fish.

The colour patterns are a surprising camouflage - Full Size

Some species of Cone snail can have up to 100 different neurotoxins which allow the snail detect and sting the fish it wants to eat. This also makes them significant for medical research.

Image sequence showing hunting behaviour of the Cone snail

The venom of a Cone snail is exceptionally dangerous. Many species contain a complex mix of different toxins. The risk to humans handling live specimens is high. A sting from a small species might be no worse than a hornet sting. However a sting from a larger species like Conus geographus can cause fatalities with a lethal dose of 0.001-0.003mg/kg making it the most venomous creature on the planet.

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Spikes

The Venus comb murex uses spines as protection against predation. This can be particularly striking and we can imagine quite a hindrance to any passing fish.

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Another example of a curious spiny snail are those of the Alviniconcha genus which live in the deepest parts of the ocean by the deep sea vents.

Alviniconcha strummeri: “Because they look like punk rockers in the 70s and 80s and have purple blood and live in such an extreme environment, we decided to name one new species after a punk rock icon.”

Glow in the Dark

Cluster-wink snails like Hinea brasiliana have an adaptation which allows them to bioluminece. When something disturbs them they give off a rapid pulse of bright flashes of green/blueish light. This light is so bright that it is thought to dazzle attacking creatures like crabs.

It may also act like a burglar alarm in that it will draw the attention of larger predators which might then eat the thing bothering the snails.

This image shows examples of the clusterwink snail H. brasiliana emitting bioluminescent light

The way the shell diffuses the specific wavelength of light is surprising as it is more efficient than any commercial light diffuser.

Research: "It's rare for any bottom-dwelling snails to produce bioluminescence," Wilson said. "So its even more amazing that this snail has a shell that maximizes the signal so efficiently."

Iron Coating

The scaly foot gastropod Crysomallon squamiferum#https://en.wikipedia.org/wiki/Scaly-foot_gastropod) is an example of a snail that also lives deep in the ocean by the deep sea vents. The snail's foot is very unusual in that it is armored with iron-mineralised sclerites, composed of iron sulphides greigite and pyrite. No other animal is known to use iron sulfides in this way.

The sclerites of Kairei population is strongly magnetic due to the greigite (sulfur equivalent of magnetite) content and stick to magnets.

The snail's shell is also unusual in that is is made of three layers. Each layer is of a different material (including more iron suflide). The composition of the shell protects the snail from predators. The impact of the force of a crabs claw for example is dissipated around the shell preventing the crab from cracking open the shell.

Researcher: http://www.zoo.ox.ac.uk/group/oceans/people/CC.html

Friday, 7 August 2015

Cat Righting Reflex

Today's trivia is all about a remarkable ability of cats to land on their feet.

This ability is know as the Cat Righting Reflex, and is a remarkable to see in action. It has also been fairly extensively tested. By tested I mean scientists spend time dropping cats and seeing what they do.

The ability is a combination of the cats highly developed reflexes and its flexible body. The backbone is surprisingly flexible, and they have no functioning collarbone which allows further flexibility.

1) The cat can detect which way is up, either via vision or by its sense of balance. (works when blindfolded).

2) The cat then draws in its front legs and extends its hind legs. It starts a large body twist with the front half of its body, which produces a smaller turn in the rear section.

3) Then the cat extends its front paws, and draws in its rear paws, performing the complimentary turn with its rear half.

4) When both halves are aligned, it extends its paws and braces for impact.

Images of a falling cat which appeared in the journal Nature in 1894, captured in a chronophotography by Étienne-Jules Marey.

NASA

Some researchers where investigating this effect and describing it in a mathematical model. This caught NASA's attention so they funded the research which lead to the publication of "A Dynamic Explanation of the Falling Cat Phenomenon" in 1969.

NASA's interest lay in the fact that they could use this research to develop maneuvers that would help astronauts orient their bodies in the weightless conditions of space, during a spacewalk for example.

Kane worked with NASA and used his equations to develop moves which were tested by a gymnast on a trampoline. The gymnast is able to use a combination of his hips and arms to orient himself midair.