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Brrrr! Celebrating the coldest day ever

Today we celebrate an event that may be somewhat unthinkable on this day to our Northern Hemisphere friends, especially everyone suffering in the US heat. On this day, back in 1983, the coldest ever temperature on earth was recorded at Vostok Station, Antarctica.

So how cold was it? Well, believe it or not, but exactly 19 years ago, the poor folk at Vostok Station recorded an icy -89.2°C (-128.6°F).

Ice crystals on a frozen stream.
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That’s pretty darn chilly…  Certainly not a temperature you want to be exposed to for any length of time.  Prolonged exposure to very cold temperatures has some interesting effects on the body.

Goose pimples and shivers

When the temperature falls below 8°C, touch sensitivity starts being compromised.  Goose pimples appear, lifting hair follicles as the body tries to protect itself from the cold. Unfortunately this does not help us humans much, because we don’t have enough body hair to have a significant effect, but you can imagine how this can be very useful to an animal with a dense fur coat.

The next step is shivering, as the body starts to increase its heat production by working the muscles – shivering is said to increase the body’s heat production five-fold.

Skin discolouration

Your skin also starts doing strange things. From below 10°C, the surface blood vessels start to dilate (your skin becomes red). As it gets colder, the blood vessels start constricting again, to avoid heat loss through your extremities. This is followed by alternating periods of dilation and constriction, as the body tries to balance the supply of oxygen and nutrients to the skin, with protection from heat loss. So you may start sporting an interesting blend of red and white skin tones.

Frostbite

During extended exposure to cold, the body has to start making decisions on how its available heat should be best applied.  In order to keep vital organs warm and avoid hypothermia, our extremities – fingers, feet, ears, nose – will be allowed to cool down, and blood flow to the extremities will also be reduced (to avoid blood cooling down as it circulates to the extremities). If this situation persists, it can lead to frost-bite, where the cells close to the skin surface start freezing and die. When heat returns to these cells, it results in swelling and blisters, forming a hardened black layer.

In extreme conditions, the frostbite can reach deeper layers of muscle and bone, resulting in permanent tissue damage, and ultimately amputation of body parts – a fate that has befallen many polar explorers and extreme mountaineers.

Hypothermia

Even though the body will do its best to maintain its core temperature, even sacrificing body parts in the process, it cannot keep up the heat if exposure to extreme cold continues.  Next the body will slow its metabolism to minimize blood flow and limit energy loss. At some point, however, the body core starts to cool, and hypothermia sets in. Not much of a core drop is needed for this – clinically, hypothermia sets in when the core temperature drops below 35°C.

First symptoms of hypothermia include reduced motor skills and slowed reaction times. Judgment also becomes impaired, with the dangerous result that the hypothermia sufferer may lose the ability to recognize the condition.

As the core temperature drops below 35°C, the body starts shivering more violently in an attempt to reverse the situation. You get more sluggish and tired, with a strong need to give up and go to sleep. Below 32°C the shivering stops, as there is no energy to keep it going, resulting in even quicker heat loss.

Unconsciousness sets in when the body core drops below 30°C. In a final primal attempt to avoid death, the heart rate and breathing slows down severely, to the point where the metabolism is so slow that the sufferer basically appears to be dead.

Below 28°C cardiac arrhythmias become more common. If the sufferer has not yet died, the heart finally stops beating at a core temperature of about 20°C.

Gender and age matters

Interestingly, women can survive extreme cold better than men. The temperature gradient from skin to body core is greater in women – women’s bodies will more readily allow the skin surface and extremities to cool down, while better protecting core temperature. So while a woman may sooner suffer frostbite, her warm core is likely to keep her alive longer. Women also tent to have a higher subcutaneous fat percentage, further helping to protect core temperature.

Age also plays a role, with people losing their ability to handle extreme cold as they age. Children are more likely to recover from the effects of extreme hypothermia – their organs appear less likely to be affected by physical stresses that may be fatal to older organs.

(Source: Science of the Cold)

Brrrrrr! Chilling stuff!  Suddenly the chilly New Zealand mornings seem decidedy mild. Enjoy the weather – whether you’re basking in the northern summer heat or shivering in the southern winter cold.  It could have been worse!

Some slithering stories on World Snake Day

So today is World Snake Day. Which is quite an amusing thought when you live in New Zealand, where there are no snakes. OK, that’s not exactly true – we have snakes, but not of the terrestrial variety – a few sea snakes have been known to laze around our waters, if somewhat irregularly.

The frightening Dispholidus jellytypus, one of New Zealand’s few indigenous snakes. Best advice when you come across one is to eat it before it eats you!
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So why don’t we have any land snakes in New Zealand? After all, eons ago, when the New Zealand land mass first broke away from Australia, mammals and snakes were already sufficiently distributed that in all likelihood the island of New Zealand started out with its fair share of snakes.

It turns out that over many millions of years, as the climate changed and the world went through the most recent ice age, the snakes on the island, as well as most mammals, were unable to survive, and they became extinct. While numerous animal species have since been reintroduced to New Zealand, and various species of birds have returned, snakes were kept out, maintaining our current snake-free habitat. Similarly, many other island countries such as Hawaii, Ireland, Greenland and Antarctica are also snake-free.

To be honest, I am quite happy with the situation as is – like Indiana Jones, I’m not a great fan of the slimy suborder of Serpentes. Not that I don’t find them fascinating, but after numerous close encounters of the slithering kind, while hiking and travelling in Africa, I just prefer my current situation of having a significant body of water between me and them.

Here’s to all the snake lovers out there – I hope you have a great World Snake Day, wherever you are. Me, I think I’ll be snacking on some jelly snakes to celebrate.

Learn about Composting Day

We live in a “disposable” society. Without giving it a second thought, any items considered useless or unnecessary are quickly disposed of in the garbage bin.  Food scraps, from coffee grinds to fruit and vege peels to eggshells, represent the bulk of the waste the modern household generates each day.  And in reality the majority of this waste is not useless at all.

Composting is one of the easiest ways to do our bit for the planet by recycling and putting our waste to good use. By putting aside a small area in your garden for a compost pile, and regularly turning and watering the pile, you will soon be the proud owner of a valuable supply of healthy organic compost.

Of course, what you are really doing by turning and watering the waste pile, is facilitating a wonderfully complex science experiment.  While micro-organisms such as bacteria and fungi break down and change the chemistry of the organic waste, macro-organisms like earthworms, mites, slugs, ants and spiders go to work biting, tearing, chewing and grinding the waste into finer material.

Give it a go – its good for the garden and its even better for the planet!

Compost created from food scraps and garden waste is a great mulch and soil additive, providing the same benefits as chemical fertilizers with none of the harmful side-effects.
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