The Last March of the Emperor Penguins
A THE emperor penguin is an impossible bird. It breeds in the middle of winter in some of the coldest places on Earth, surviving temperatures as low as -50℃ and hurricane-force winds. In March or April, just as the Antarctic winter begins, the birds waddle across the sea ice to their colonies, where they mate. After the egg is laid, the females head back to sea to feed, leaving the males behind to incubate it. By the time the females return in July or August, when the eggs hatch, the males will have spent almost four months huddling together in the bitter cold without eating, losing half of their body weight. This extraordinary lifestyle has made the emperors famous. They have even been held up as role models by evangelical Christians. But these breathtaking birds will soon have to face the one thing they haven't evolved to cope with: warmth. Fast-forward a few decades, and many colonies will be on the road to extinction. Are we witnessing the last march of the emperor penguins?
B Finding out what's going on with emperor penguins is a huge challenge as almost all of their colonies are exceedingly difficult to get to. In fact, it was only this year that the first global census of the birds was published, based on an automated analysis of satellite images by the British Antarctic Survey. This revealed four previously unknown colonies, bringing the total to 46 (see map), and put the number of adults at 600,000, nearly double earlier estimates. That might sound like good news, but it's impossible to say whether the overall number of birds is rising or falling. "It's simply that we now have a better method to find them-remote sensing," says team member Phil Trathan.
C By far the most comprehensive insight into the highs and lows of emperor populations comes from just one colony, which happens to be next to the Dumont d'Urville research station on the Adelie coast of Antarctica. "After a snowstorm, they can see how many eggs have got frozen, and how many chicks have died," says biologist Stephanie Jenouvrier of the Woods Hole Oceanographic Institution in Massachusetts, who studies the birds. This relatively small colony of 2500 birds featured in the 2005 blockbuster documentary March of the Penguins.
D The Dumont d'Urville emperor's have been closely monitored since 1962. During the 1970s and early 80s, the average winter temperature was-14.7℃, compared with a more typical-17.3℃. This "warm spell" reduced the extent of winter sea ice by around 11 percent and the penguin population by half. "When sea ice decreased, it caused strong mortality of emperor penguins," says Jenouvrier. Why are emperors so sensitive to changes in sea ice? Well to start with, most never set foot on land. They aren't agile enough to scale the steep rocks and ice precipices that guard most of Antarctica's shoreline. All but two of the 46 colonies are on fast ice-sea ice stuck fast to the shore. So if the sea ice forms late or breaks up early, it won't last for the eight months or so these large birds need to breed and raise chicly.
E "Early break-up of sea ice can cause catastrophic breeding failure," says Trathan. Emperors live around 20 years, so colonies can survive a few bad breeding seasons, but persistent changes can be disastrous. What's more, emperors moult every year in January or February. The birds would freeze to death if they tried to swim during the 30 or so days it takes to grow new feathers, so they must find ice floes to shelter on that are large enough to survive this period. This may be an even more demanding period in the emperors' lives than the winter, because they have little time to fatten themselves up beforehand. "The adults are reliant on stable sea ice for moulting, and for me, that's the greatest concern," says Gerald Kooyman of Scripps Institution of Oceanography, one of the world's leading emperor penguin biologists. "They don't have any options. They have to moult."
F Last, but not least, the source of much of the penguins' energy, directly or indirectly, is krill-and krill also depend on sea ice. Young krill shelter and feed under it. "The sea ice is the basis of the Antarctic ecosystem," says Jenouvrier. For now, there is still plenty of sea ice. In fact, the extent of Antarctic sea ice in winter has increased slightly over the last 30 years. This has been caused by stronger winds blowing sea ice further away from the land, with more ice forming in the open water exposed by this movement. The stronger winds are thought to be a consequence of ozone loss, rather than global warming.
G But unlike the Arctic Ocean, where thick sea ice used to survive from year to year, in Antarctica almost all the sea ice melts every year. That means the extent of winter sea ice changes rapidly in response to any change in conditions. This can be seen around the rapidly warming Antarctic Peninsula, where winter sea ice extent is falling 1 or 2 percent each year. Here one small emperor colony, on the Dion Islands, has already died out. When it was discovered in 1948 it was home to 300 adults. By 1999， just 40 remained and 10 years later they were all gone. Though no one knows for sure what caused the colony's demise, it coincided with a decline in the duration of winter sea ice. On the peninsula, populations of the other Antarctic native penguins, the Adelie and chinstrap, are also plummeting, probably because of the changing environment and declining krill. Matters haven't been helped by an invasion of non-native gentoo penguins, and other species like the king and macaroni penguins could follow.
H What's happening on the peninsula today could be happening all around Antarctica in the decades to come. "With a doubling of greenhouse gas concentrations over the next century, we estimate that the extent of Antarctic sea ice would decrease by about one third, says John Turner, a climatologist with the British Antarctic Survey. Earlier this year the emperor penguin was added to the IUCN's Red List for species threatened with extinction in the near future-"near" meaning in a century or two. When Jenouvrier's team used the observations at Dumont d'Urville to predict what will happen as the continent warms, they concluded that the colony is likely to decline by 81 per cent by 2100 and be heading towards extinction.
I That is in line with a 2010 study by a team including Jenouvrier and David Ainley of the California-based ecological consultants H. T. Harvey and Associates. It predicted that all emperor colonies north of 70 degrees latitude- about 35 percent of the total population-would decline or disappear if the world warms by 2℃, although a few colonies south of 73 degrees might grow a little. This might not sound too bad, but both these studies are based on what increasingly appear to be overly optimistic assumptions. If we continue as we are, the global temperature will climb above 2℃ before 2050, on course to a 5 or 6℃ rise by 2100. "If the earth warms by 5 or 6 degrees, I can't see that there's going to be much sea ice left anywhere on Earth," says Ainley. And if the sea ice vanishes, the emperor penguins will vanish too.
Water Filter
A An ingenious invention is set to bring clean water to the third world, and while the science may be cutting edge, the materials are extremely down to earth. A handful of clay yesterday's coffee grounds and some cow manure are the ingredients that could bring clean, safe drinking water to much of the third world.
B The simple new technology, developed by ANU materials scientist Mr. Tony Flynn, allows water filters to be made from commonly available materials and fired on the ground using cow manure as the source of heat, without the need for a kiln. The filters have been tested and shown to remove common pathogens (disease-producing organisms) including E-coli. Unlike other water filtering devices, the filters are simple and inexpensive to make. "They are very simple to explain and demonstrate and can be made by anyone, anywhere," says Mr. Flynn. "They don't require any western technology. All you need is terracotta clay, a compliant cow and a match."
C The production of the filters is extremely simple. Take a handful of dry, crushed clay, mix it with a handful of organic material, such as used tea leaves, coffee grounds or rice hulls, add enough water to make a stiff biscuit-like mixture and form a cylindrical pot that has one end closed, then dry it in the sun. According to Mr. Flynn, used coffee grounds have given the best results to date. Next, surround the pots with straw; put them in a mound of cow manure, light the straw and then top up the burning manure as required. In less than 60 minutes the filters are finished. The walls of the finished pot should be about as thick as an adult's index. The properties of cow manure are vital as the fuel can reach a temperature of 700 degrees in half an hour and will be up to 950 degrees after another 20 to 30 minutes. The manure makes a good fuel because it is very high in organic material that bums readily and quickly; the manure has to be dry and is best used exactly as found in the field, there is no need to break it up or process it any further.
D "A potter's din is an expensive item and can take up to four or five hours to get up to 800 degrees. It needs expensive or scarce fuel, such as gas or wood to heat it and experience to run it. With no technology, no insulation and nothing other than a pile of cow manure and a match, none of these restrictions apply," Mr. Flynn says.
E It is also helpful that, like terracotta clay and organic material, cow dung is freely available across the developing world. "A cow is a natural fuel factory. My understanding is that cow dung as a fuel would be pretty much the same wherever you would find it." Just as using manure as a fuel for domestic uses is not a new idea, the porosity of clay is something that potters have known about for years, and something that as a former ceramics lecturer in the ANU School of Art, Mr. Flynn is well aware of. The difference is that rather than viewing the porous nature of the material as a problem — after all not many people want a pot that won't hold water — his filters capitalize on this property.
F Other commercial ceramic filters do exist, but, even if available, with prices starting at US$5 each, they are often outside the budgets of most people in the developing world. The filtration process is simple, but effective. The basic principle is that there are passages through the filter that are wide enough for water droplets to pass through, but too narrow for pathogens. Tests with the deadly E-coli bacterium have seen the filters remove 96.4 to 99.8 per cent of the pathogen — well within safe levels. Using only one filter it takes two hours to filter a litre of water. The use of organic material, which burns away after firing, helps produce the structure in which pathogens will become trapped. It overcomes the potential problems of finer clays that may not let water through and also means that cracks are soon halted. And like clay and cow dung, it is universally available.
G The invention was born out of a World Vision project involving the Manatuto community in East Timor The charity wanted to help set up a small industry manufacturing water filters, but initial research found the local clay to be too fine — a problem solved by the addition of organic material. While the AF problems of producing a working ceramic filter in East Timor were overcome, the solution was kiln-based and particular to that community's materials and couldn't be applied elsewhere. Manure firing, with no requirement for a kiln, has made this zero technology approach available anywhere it is needed. With all the components being widely available, Mr. Flynn says there is no reason the technology couldn't be applied throughout the developing world, and with no plans to patent his idea, there will be no legal obstacles to it being adopted in any community that needs it. "Everyone has a right to clean water, these filters have the potential to enable anyone in the world to drink water safely," says Mr. Flynn.
High Speed Photography
A Photography gained the interest of many scientists and artists from its inception. Scientists have used photography to record and study movements, such as Eadweard Muybridge's study of human and animal locomotion in 1887. Artists are equally interested by these aspects but also try to explore avenues other than the photo-mechanical representation of reality, such as the pictorialist movement. Military, police, and security forces use photography for surveillance, recognition and data storage. Photography is used by amateurs to preserve memories, to capture special moments, to tell stories, to send messages, and as a source of entertainment. Various technological improvements and techniques have even allowed for visualising events that are too fast or too slow for the human eye.
B One of such techniques is called fast motion or professionally known as time-lapse. Time-lapse photography is the perfect technique for capturing events and movements in the natural world that occur over a timescale too slow for human perception to follow. The life cycle of a mushroom, for example, is incredibly subtle to the human eye. To present its growth in front of audiences, the principle applied is a simple one: a series of photographs are taken and used in sequence to make a moving-image film, but since each frame is taken with a lapse at a time interval between each shot, when played back at normal speed, a continuous action is produced and it appears to speed up. Put simply: we are shrinking time. Objects and events that: would normally take several minutes, days or even months can be viewed to completion in seconds having been sped up by factors of tens to millions.
C Another commonly used technique is high-speed photography, the science of taking pictures of very fast phenomena. High-speed photography can be considered to be the opposite of time-lapse photography. One of the many applications is found in biology studies to study birds, bats and even spider silk. Imagine a hummingbird hovering almost completely still in the air, feeding on nectar. With every flap, its wings bend, flex and change shape. These subtle movements precisely control the lift its wings generate, making it an excellent hoverer. But a hummingbird flaps its wings up to 80 times every second. The only way to truly capture this motion is with cameras that will, in effect, slow down time. To do this, a greater length of film is taken at a high sampling frequency or frame rate, which is much faster than it will be projected on screen. When replayed at normal speed, time appears to be slowed down proportionately. That is why high-speed cameras have become such a mainstay of biology.
D In common usage, high-speed photography can also refer to the use of high-speed cameras that the photograph itself may be taken in a way as to appear to freeze the motion, especially to reduce motion blur. It requires a sensor with good sensitivity and either a very good shuttering system or a very fast strobe light. The recent National Geographic footage—captured last summer during an intensive three-day shoot at the Cincinnati Zoo—is unprecedented in its clarity and detail. "I've watched cheetahs run for 30 years," said Cathryn Milker, founder of the zoo's Cat Ambassador Program. "But I saw things in that super slow-motion video that I've never seen before." The slow-motion video is entrancing. Every part of the sprinting cat's anatomy—supple limbs, rippling muscles, hyperflexible spine—works together in a symphony of speed, revealing the fluid grace of the world's fastest land animal.
E But things can't get any more complicated in the case of filming a frog catching its prey. Frogs can snatch up prey in a few thousandths of a second—striking out with elastic tongues. Biologists would love to see how a frog's tongue roll out, adhere to prey, and roll back into the frog's mouth. But this all happened too fast, 50 times faster than an eye blink. So naturally people thought of using high-speed camera to capture this fantastic movement in slow motion. Yet one problem still remains—viewers would be bored if they watch the frog swim in slow motion for too long. So how to skip this? The solution is a simple one—adjust the playback speed, which is also called by some the film speed adjustment. The film will originally be shot at a high frame (often 300 frames per second, because it can be converted to much lower frame rates without major issues), but at later editing stage this high frame rate will only be preserved for the prey catching part, while the swimming part will be converted to the normal speed at 24 frames per second. Voila, the scientists can now sit back and enjoy watching without having to go through the pain of waiting.
F Sometimes taking a good picture or shooting a good film is not all about technology, but patience, like in the case of bat. Bats are small, dark-colored; they fly fast and are active only at night. To capture bats on film, one must use some type of camera-tripping device. Photographers or film-makers often place camera near the bat cave, on the path of the flying bats. The camera must be hard-wired with a tripping device so that every time a bat breaks the tripping beam the camera fires and it will keep doing so through the night until the camera's battery runs out. Though highly-advanced tripping device can now allow for unmanned shooting, it still may take several nights to get a truly high quality film.
G Is it science? Is it art? Since the technique was first pioneered around two hundred years ago, photography has developed to a state where it is almost unrecognisable. Some people would even say the future of photography will be nothing like how we imagine it. No matter what future it may hold, photography will continue to develop as it has been repeatedly demonstrated in many aspects of our life that "a picture is worth a thousand words."
