Law human: March 2015

Sunday, March 29, 2015

Ancient water cache may be pristine primordial soup

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Deep rocks have been cracked open and water isolated for billions of years released – the liquid may represent Darwin's “warm little pond” where life arose

IT IS the closest we have ever come to finding Earth's primordial soup. Ancient rocks deep underground contain water that has been locked away for billions of years. It may never have been touched by life.

In 2007, geochemist Barbara Sherwood Lollar at the University of Toronto in Canada and her team found treasure in a copper mine. Water gushing out of cracks in the rock, caused by mining, turned out to be over a billion years old. Now the group has made a similar find in a second mine, suggesting ancient rocks could be riddled with such time capsules, right back to the early days of life on Earth.

Sherwood Lollar's team is now scouring the water for ancient forms of life, perhaps unknown to science. So far it seems it holds no life, but that is just as exciting because it means the water they found may be identical to that in which life began.

If that's the case, it opens up an extraordinary opportunity to understand how life got started on Earth, and where (see "Beginner's guide to the origin of life"). The find could also offer insights into how life may survive on other planets.

Sherwood Lollar first got a whiff of the hidden water over a decade ago, deep inside the Kidd Creek Mine in Timmins, Ontario, Canada. In a corridor more than 2 kilometres beneath the surface, she caught a whiff of gas from a fracture in the rock. Water dripped from the hole. Subsequent analyses revealed it to be between 1.1 and 2.7 billion years old (Nature, doi.org/tgw). The smell came from the sulphurous gases mixed in with the water, which also holds methane and hydrogen.

Crucially, as far as the team could tell, the water contained no trace of life. "It speaks to this question of whether we can find an exotic small part of this planet that has not been touched by life," says Sherwood Lollar. "These fractures may have been isolated long enough that they retain chemistry that reflects the same kind of processes that were taking place before there was life on Earth. At that time, presumably the whole planet would have looked something like this."

The discovery could have been a one-off, so the team has been looking for other places where ancient water exists in deep rocks. Last month at the Goldschmidt conference in Sacramento, California, team member Chelsea Sutcliffe presented their results from two mines in the Sudbury basin, also in Ontario.

Like Timmins, the mines are dug into rock that is billions of years old. Sutcliffe collected water from 1.3 and 1.7 kilometres down, and so far it looks very similar to the Timmins water. The chemicals in the water are similar, and isotope ratios suggest it is similarly old. The team are now running further analyses: the noble gases in the water samples will provide a fairly precise age.

"If they are seeing the same thing at Sudbury, that's pretty powerful," says Tullis Onstott of Princeton University. This water is "an abiotic fringe zone – a place where life could exist but doesn't yet", he says. "This is a zone that's been trapped for billions of years, providing a geological experiment on the genesis of life."

At most, the Timmins and Sudbury water is 2.7 billion years old – the age of the rock it is trapped inside. That's about a billion years after life got started, so the researchers are not suggesting they have bottled the actual primordial soup in which life began. But the chemistry they are seeing corresponds to water that could have given rise to life.

"Geochemically, it's the kind of site that has been invoked for the origins of life on our planet," says Onstott. "Yet here we see it isolated from the present-day DNA world."

There are two leading theories for where life got started on Earth. Perhaps the most famous is Darwin's "warm little pond" – a soup of organic chemicals bathed in sunlight. The other, which has gained popularity in recent years, is that deep-sea vents at the bottom of the ocean acted as a cradle for life, offering both heat and nutrition via fluids pumped up through Earth's crust.

That's where the ancient water from the Ontario mines comes in. The rocks they are held in were formed by hydrothermal vent systems at the bottom of the ocean, billions of years ago.

"I would say this is as close as we have come to bottling the warm little pond, in a warm little fracture," says Sherwood Lollar. Onstott agrees: "They are literally like Darwin's warm little pond without the light."

Having bottled Earth's primordial soup, the researchers are now probing it to see what they can learn. It may be that chemical reactions deep underground have given rise to some of the very earliest stages in the formation of life, like the generation of amino acids, or the building blocks of DNA.

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Why food is rarely the simple pleasure it once was

An exhibition at London's Science Museum and a philosophising book explore our desire for food, while another new book exposes the food industry's dark secrets

Book information
Swallow This: Serving up the food industry's darkest secrets by Joanna Blythman
Published by: 4th Estate
Price: £14.99

Book information
Appetites for Thought: Philosophers and food by Michel Onfray
Published by: Reaktion Books
Price: £14.95/$24.95

Guts talk at an intriguing exhibition at London's Science Museum (Image: Jennie Hills/Science Museum, London|Science & Society Picture Library)

Cravings: Can your food control you? Science Museum, London, until January 2016

SOME years ago, I was friendly with a family who ran a venison smokery. They were expanding their product line to include a venison salami. On one visit, they presented me with piles of sliced sausage: which recipe did I prefer?

My first mouthful was a disappointment. The sausage tasted of generic salami, hardly even of meat, and though I knew otherwise, it was hard to imagine that any deer had perished in the making of it. My second was just as bad. The body language of my hosts was revealing. My weak-beer praise simply confirmed what this conscientious family already knew: no tweaks were going to save their experiment.

As my friends discovered, you don't need to be a big food processor to hit big problems. Since mass production renders the best ingredients to tasteless slurry, your job is to rescue, recreate or, frankly, fake the tastes and aromas you killed off in making your product.

The keen home cook's first-aid kit includes fat, salt and sugar. But the food industry also uses (among many other extras) acids, enzymes, texturisers, blood plasma and grim-sounding powdered dairy essences. In Swallow This, the latest of a string of superior industry exposés, food journalist Joanna Blythman explains how far manufacturers will go to produce cheap foods that taste consistent, while retaining that "just-cooked" feel.

Her page about salami, for example, features company literature describing a meat glue made from the enzyme transglutaminase, blended with animal protein and vitamin B9: "Salami Dry Express B9 decreases ripening time by up to 20 per cent, creates a more... appealing colour in less time, offers improved casing peeling and... sausage aroma. Improved slicing properties reduce wastage by up to five per cent, while shorter processing and storage times also provide financial advantages."

Each promise listed sounds reasonable. But taken together, they suggest an approach to food that can only disgust consumers. And this, chiefly, is why the food processing industry is growing ever more secretive, ever more insincere, and, more worryingly still, ever more removed from the real science of nutrition. Its prime concern is not food, but keeping up appearances.

Everyone imagines they want an authentic home-cooked meal, even as they "require honeyed cakes, unguents and the like". This nice turn of phrase belongs to the Greek Cynic Diogenes, one of the philosophers in Michel Onfray's slim, sly volume of essays called Appetites for Thought. Rather in the spirit of Bruces' Song, Monty Python's dipsomaniacal summary of the Western philosophical tradition, Onfray dishes out morsels under chapter headings like "Nietzsche; or The Sausages of the Anti-Christ".

His simple thesis, that our minds are ruled by our stomachs, acquired a graphic reality in 2006, when Molly Smith, a 16-year-old from Cambridgeshire, UK, received a life-saving transplant. She had been born with much of her intestinal tract missing, and had never experienced hunger, thirst or any food cravings. When Molly finally ate her first solid food – a banana – she felt the stirrings of new sensations. Her guts were beginning to talk to her.

Molly's is one of the more startling stories told in Cravings, at London's Science Museum. The rich, mysterious, two-way dialogue between gut and brain that so entertained Onfray is its central theme, and serves as a playful entrée to health advice.

Though the exhibition is full of cautionary information about fat and sugar levels in many processed foods, it left this visitor hankering for the museum café. This is no bad thing. Food, any kind of food, is better than the alternative. And an exhibition about appetite ought to pique it.

This article appeared in print under the headline "Sausages of the Anti-Christ"

Planet or not, Ceres rocks

WHAT makes a planet a planet? It's nearly 10 years since the International Astronomical Union created a stir by agreeing a new classification system that kicked Pluto out of the club, demoting it to dwarf planet status.

In the intervening years it has become abundantly clear that the solar system's smaller bodies are at least as interesting as those that still enjoy full planetary status. We already think that the moons of Jupiter and Saturn are among the best places to search for alien life. Now, as spacecraft begin to map Pluto and its smaller cousin Ceres, dwarf planets are entering the limelight.

Is another round of planetary hokey-cokey on the cards? The leader of the Dawn mission is on record as saying that Ceres will turn out to be "every bit a planet as its terrestrial neighbours Mars, Earth, Venus and Mercury" (see "New dawn for Ceres"). If Ceres is a planet, so are Pluto, Eris and many others.

It doesn't really matter. In fact, reviving the debate will only detract from the excitement of exploration. Pluto's demotion was keenly felt by a generation of astronomers, both professional and amateur. Ceres has no comparable emotional pull, and nothing to gain from being promoted to planetary status.

This article appeared in print under the headline "Fifth rock from the sun?"

Twin Earths may lurk in our nearest star system

There could be two Earth-like planets within cosmic spitting distance of our own. Both are likely too close to their star to host life, but the discovery opens the possibility of other planets in the system with more temperate climates.

Alpha Centauri is a binary star system just 4.3 light years away from our own. In 2012 astronomers announced that the system had a planet, which they dubbed Alpha Centauri Bb as it was apparently orbiting the smaller of the stars, Alpha Centauri B.

The team said it was a rocky world slightly more massive than Earth. But in 2013, other researchers called into question the existence of Bb, saying the evidence wasn't good enough.

"If you ask anyone working in exoplanets, they would all have a different opinion about the existence of Alpha Centauri Bb," says Brice-Oliver Demory of the University of Cambridge.

That's why he and his colleagues have been using the Hubble Space Telescope to search for planet. They weren't able to find it, but have instead seen hints of a second Earth-sized world in the system.

Star wobble

The original claim was based on the radial velocity method – a planet-hunting technique which looks at how the gravitational pull of a planet slightly wobbles its star. Demory's Hubble search took a different approach, looking for signs of a dip in the light from Alpha Centauri B caused by the planet passing in front of, or transiting, the star. These two methods are independent of each other, so seeing Bb transit would reinforce the earlier patchy radial velocity data.

The original measurements suggested that Bb, if it exists, takes three or so days to orbit its star. But not all planets make transits as seen from Earth, because it depends on how the planet and star are aligned.

Demory's team observed Alpha Centauri B in 2013 and 2014, for a total of 40 hours. The 2013 data showed signs of a transit consistent with Bb's suggested orbital parameters, but it seemed to last slightly longer than expected, and the statistical validity of the signal disappeared when combined with the 2014 data. That doesn't mean Bb isn't there, just that if it exists, it is unlikely to transit as seen from Earth.

That still leaves a puzzle over what caused the 2013 signal. The team ruled out errors with Hubble itself or spots on the surface of the star, which can sometimes be mistaken for exoplanets.

They also dismissed the possibility of interference from Alpha Centauri A, the other star in the binary system, or from an unrelated, more distant star system that could have just been passing behind.

Scorchingly close

The only explanation left was that there is another planet in the system. The observations point to an Earth-sized planet with a year lasting no more than 20.4 days, putting it slightly further out than Bb but still scorchingly close to the star.

Astronomers have confirmed nearly 2000 exoplanets so far, and the evidence suggest many stars host multiple planets, just like our own solar system. That means confirming the discovery of one planet around Alpha Centauri B – even one with a hot, close orbit – hints at other planets in the system that might be more hospitable. "If you see one planet, the chance is there are other planets in the system," says Demory.

"They work they've done holds tight; they give a very well balanced view on what this transit could be," says Paul Wilson of the Paris Institute of Astrophysics in France. He's not sure there is enough evidence yet to support a full discovery, but is keen to encourage the team. "I hope they will be able to detect an Earth-sized planet through the transit method. That would be fantastic."

Unfortunately it's going to be difficult to confirm either of these planets with our current generation of telescopes. Hubble could do it, but it would have to stare at Alpha Centauri for 20 days with no guarantee of finding anything, which would be seen as a waste of time for our most important space telescope, says Demory.

Upcoming instruments like the European Extremely Large Telescope Movie Camera or the Cheops space telescope might be able to see the new planet, but the best option could be a small satellite dedicated to staring at Alpha Centauri. Such a mission would only cost around $2 million. "It could be crowdfunded," says Demory. Anyone fancy chipping in to find our nearest neighbours?

Reference: arxiv.org/abs/1503.07528

How landscapes mould language and lives

Our surroundings can influence the words we use and feed into life's twists and turns, as two new books explore

Book information
Landmarks by Robert Macfarlane
Published by: Hamish Hamilton
Price: £20.00

Book information
The Fish Ladder: A journey upstream by Katharine Norbury
Published by: Bloomsbury Circus
Price: £16.99

Dyffryn Mymbyr in Wales, a chilly hotbed of poetic literature (Image: Peter Marlow/Magnum)

VOCABULARY is an ever-changing terrain, reshaped by tongue and trends, just as the elements and town planners reconfigure the landscape of Britain. And the relationship between place and name, argues Robert Macfarlane, is deep-rooted and undervalued.

"Language is fossil poetry," he writes, quoting 19th-century US essayist Ralph Waldo Emerson, and Landmarks is a project Emerson would have recognised: a "word-hoard". It attempts to preserve language and use it to pull us closer to our surroundings. This hoard is needed because specialised vocabularies are being burned off by apathy and urbanisation, says Macfarlane. In the mouths of the unimaginative, he reasons, generic language is shaping a "blandscape".

Landmarks serves as a convivial field guide to the authors who have inspired Macfarlane's magnificent writing: eco-philosophers such as John Muir, Roger Deakin and Nan Shepherd figure strongly. It has glossaries brimming with regional colloquialisms, from the poetically exact "ammil" – a term for the sparkle of morning sun through hoar frost – to the bawdy "wind-fucker", a kestrel.

The tenth glossary is left playfully blank, hungrily awaiting future words, because Macfarlane is no doom-monger. Words, he says, "act as a compass to sing [the land] back into being".

An ecologist, linguist and academic, Macfarlane is not above admitting his infatuation with Britain's diverse landscape. "Nature does not name itself," he writes. "Language is always late for its subject. Sometimes on top of a mountain I just say, 'Wow'."

In The Fish Ladder, her first book, Katharine Norbury cannot afford to be so ingenuous. How truthfully she writes will determine whether her series of river walks from sea to source will be seen as a sufficiently heroic quest.

Her project is driven by her miscarriage and subsequent depression, making this a book as much about grief and motherhood as about landscape.

There are moments of quiet drama, such as her waking on moorland to find a stag standing over her. Still, her journeys are not epic. She acknowledges the semi-industrial nature of her surroundings. Those fish ladders, for instance, are structures that allow fish to bypass dams, leaping barriers on the way to their spawning grounds. They allow salmon and hydroelectricity to co-exist.

Less happily, there is something touristic about her fleeting visits, and their meaning is occasionally overthought, as in "the fact we'd brought sandwiches seemed significant, somehow indicative of a need for self-sufficiency". She is only ever passing through.

The Fish Ladder is a valuable addition to the contemporary nature-memoir canon – although Norbury's life of second homes and Latin family mottoes highlights the irony that so few of today's memoirs about the natural world are written by those who work such harsh, remote lands.

This article appeared in print under the headline "Tied to the land"

Benjamin Myers is the author of the novel Beastings

Great Barrier Reef reserves protected fish from cyclone

Finally, some good news for fish. Banning fishing in certain areas doesn't just boost local fish populations, it also helps them recover from climate events like tropical cyclones.

The news comes from Australia's Great Barrier Reef. Michael Emslie from the Australian Institute of Marine Science and colleagues analysed data from underwater surveys done there between 1983 and 2012.

They found that when protected areas were expanded to cover 40 per cent of the Great Barrier Reef Marine Park, the biomass of coral trout, an important fishery species, doubled inside many of the areas.

"It's heartening to know the green zones are working as we had expected," says Emslie.

When a large tropical cyclone swept through the area in 2009, the biomass of coral trout declined outside, but not inside, the reserves. Emslie says that since the fish tended to grow bigger inside the reserves, they were able to spawn more larvae, which allowed a faster recovery.

Severe tropical cyclones are likely to become more frequent as a result of climate change, says Elizabeth Madin from Macquarie University in Sydney, Australia. "One of the unique things that this study does is illustrate the point that we can help curb the negative effects of climate change by enacting local solutions," she says.

Given the effect the reserves had on the Great Barrier Reef, such measures would be likely to have an even greater impact in areas of more intense fishing, such as around large coastal populations, said co-author Hugh Sweatman, of the Australian Institute of Marine Science in Townsville, Queensland.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.01.073

Should we thank god for civilisation?

The idea that religion led to modernity is gaining momentum. But that doesn't mean it should lead civilisation now

(Image: Vincent J. Musi/National Geographic Creative)

ABOUT 10,000 years ago, our ancestors began the greatest transformation in human history, abandoning the nomadic lifestyle that had long served them well in favour of permanent villages.

The origin of this "Neolithic revolution" is contentious. The answer once seemed clear: food. Farming was more efficient than foraging and so people gravitated towards it. Cities, writing and organised religion soon followed.

In recent years, though, this model has been challenged by archaeological discoveries. The most important is Göbekli Tepe in Turkey: a cluster of 11,000-year-old buildings with spectacular statues and other monumental architecture. The archaeologists who found it interpreted these as having a ceremonial purpose: a "cathedral on a hill", as one put it.

Yet the people who built them were nomads, not farmers. So the radical suggestion now is that it was not agriculture that drove the revolution, but religion. Some archaeologists oppose this idea, arguing that the ruins could have been domestic buildings, or were once surrounded by dwellings that did not survive. But the ceremony-first model is in the ascendancy, supported by further evidence unearthed in the Levant.

Now comes news that another ancient civilisation – the Maya – may also have had spiritual roots. Their oldest city, Ceibal, seems to have begun as a place where hunter-gatherers assembled for religious festivals (see "Jungle festivals led to first Maya cities").

The parallels are intriguing. Maya civilisation developed in geographical isolation from the Old World, and several thousand years later. If it followed the same path, perhaps that tells us something profound about human cultural evolution.

Some secularists dislike the idea that spiritual needs drove the rise of civilisation. They fret that it will reinforce or restore religion's central place in society. But just because spirituality may have led to civilisation, it doesn't follow that it should lead it now. If religion did have an early founding role, we must acknowledge this, learn from it – and move on.

This article appeared in print under the headline "Thank god for civilisation"

Killer seals develop a taste for shark guts

(Image: Chris Fallows)

It's like Jaws but, this time, the shark is on the menu. In an incident that turns the phrase "shark attack" on its head, a seal has repeatedly attacked, killed and partially devoured medium-sized sharks. If this turnabout proves common, ecologists may need to reassess the role of seals in marine ecosystems.

More than a decade ago, Chris Fallows, a dive-boat operator based in Cape Town, South Africa, happened to see a young Cape fur seal chasing, tossing and eventually killing a blue shark. The seal then ate the shark's internal organs, which are the most energy-rich part of a shark's body.

Then, in 2012, it happened again. This time, Fallows was underwater photographing 10 blue sharks when a young male Cape fur seal arrived and proceeded to chase and kill five of the sharks, once again eating only their guts.

He has now published a study on this discovery with his colleagues.

Ordinarily, both seals and blue sharks, which are roughly the same size, prey on much smaller fish, squid and other marine life. Several species of seal are also known to feed on smaller sharks, and blue sharks have been seen pursuing – but not catching – fur seals. Fallows's observations are the first time anyone has seen seals preying on such large sharks, says Hugues Benoit of the Canadian Department of Fisheries and Oceans in Moncton, New Brunswick, another of the study's authors.

Other marine mammal researchers are surprised that a seal would take on such a large, toothy challenge. "You don't want your meal to come bite you in the ass, and the shark has some potential to cause serious harm," says Dominic Tollit of SMRU Canada, a marine mammal consultancy group based in Vancouver. "Would you attack a lion if you're hungry, or would you go for something smaller?"

No one knows how commonly seals turn the tables on sharks in this way. However, Benoit suspects that it could be far more common than anyone realises – especially if most cases take place well out to sea, far from most researchers' eyes. And, if seals typically eat only the sharks' guts, their stomach contents and faeces will contain few hard parts to testify to their sharky dinners.

By chowing down on their competitors, seals could be altering ocean food webs in unexpected ways, he says, especially with seal populations booming throughout the oceans. If seals help hold down shark populations, for example, that could have a net benefit on populations of smaller fish, even if the seals also eat the same fish themselves. If so, fisheries biologists may need to take that into account in managing fish populations.

Journal reference: African Journal of Marine Science, DOI: 10.2989/1814232X.2015.1013058

Thirty new fly species found in LA's urban sprawl

(Image: Phyllis Sun)

No, it's not Damien Hirst's latest creation. The flies pinned down in this photo are from six of 30 new species discovered in the urban metropolis of Los Angeles, California.

The insects were identified as part of a project led by Emily Hartop of the Natural History Museum of Los Angeles County, where local volunteers took part by setting up 24-hour insect traps at 30 sites across the city. "For us, it seemed like a no-brainer," says volunteer Walter Renwick. "We have two young bug-crazy children, a bug-crazy dad, and a very patient mom in our household."

Hartop then sifted through 10,000 fly specimens over a three-month period to identify the new species. Conveniently, each new member of the fly genus Megaselia could be matched to one of the backyards where it had been spotted, so researchers named each species after the corresponding citizen scientist.

The finds reveal a surprising biodiversity in LA, one of the most smog-choked cities in the US.

Thursday, March 26, 2015

Asia Unites Against Poaching

Representatives from 13 Asian countries committed to immediate action to stamp out poaching at the conclusion of a four-day symposium hosted by the Nepal government in Kathmandu from February 2-6, 2015.

The Symposium: Towards Zero Poaching in Asia adopted five recommendations:

Swift and decisive action to elevate the importance and effectiveness of antipoaching initiatives and cooperation among all relevant ministries, departments and agencies within their borders, while at the same time strengthening international cooperation in the face of this serious criminal activity.
Adoption of the Zero Poaching Tool Kit and assessment of current antipoaching responses to determine improvements and close serious gaps.
Increase and improve collaboration as a successful antipoaching response is critically dependant on effectively engaging a diverse number of shareholders
Improve standards, training and support for rangers, other frontline staff and prosecutors.
Commit to identifying a Zero Poaching national contact point to effectively coordinate transboundary efforts to stop poaching.

Tika Ram Adhikari, Director General of Nepal’s Department of Wildlife Conservation and Soil Conservation, said: “Nepal was proud to host this vital conversation in Asia because we recognize that poaching is robbing us of our wildlife wealth, which includes tigers, rhinos and elephants. We cannot allow wildlife crime to continue to wrap its tentacles deeper into the region. Our individual efforts may win us a few battles, but we can only win the war if Asia presents a united front to stop the poaching, end the trafficking and wipe out demand.”

Mike Baltzer, Leader, WWF Tigers Alive Initiative, said: “This is the beginning of the end for poaching across Asia. WWF is proud to have supported this landmark meeting and is committed to be part of the new determined movement for Zero Poaching in Asia.”

Nepal was the natural host for the symposium having achieved zero poaching for two years in the past four years. At the symposium, representatives from local communities, protected areas as well as enforcement agencies shared their lessons lea

At the closing ceremony, Nepal’s legendary Chitwan National Park (CNP) also became the first global site to be accredited as Conservation Assured Tiger Standard (CA|TS).Despite the threats that CNP faces, the protected area has seen an increasingly effective management and protection regime. This further demonstrates the commitment of Nepal towards zero poaching.

Thirteen Asian countries participated in the symposium: Bangladesh, Cambodia, China, Viet Nam, Malaysia, Russia, Indonesia, Myanmar, Thailand, Nepal, India, Bhutan, and Lao PDR. Partner NGOs and other organisations included IUCN, TRAFFIC, CITES, UN Office on Drugs and Crime, US Department of Justice, SMART Partnership and Southern African Wildlife College.

WWF co-hosted the symposium with Global Tiger Forum, National Trust for Nature Conservation and the South Asian Wildlife Enforcement Network.

The symposium provides valuable direction on tackling poaching in advance of the Kasane Conference on the Illegal Wildlife Trade to be hosted by the Botswana government on 25th March 2015. This meeting follows the London Conference on the Illegal Wildlife Trade hosted by the UK government in February 2014, where 41 governments committed to taking “decisive and urgent action….” through the agreed declaration.

Tuesday, March 24, 2015

Sushi parasite inspires worm test for cancer

Dogs do it. Rats do it. Even some people seem to be able to sniff out cancer and other diseases. Now we can add the humble roundworm to the list of super-smellers.

Japanese researchers have discovered that Caenorhabditis elegans worms can detect cancer in people's urine. They are working with technology companies Hitachi and Johnan to turn the finding into a diagnostic test that can be used to catch the disease in its early stages.

"In existing tests, people must have different examinations according to the type of cancer they have", says Takaaki Hirotsu from Kyushu University in Fukuoka, Japan, who co-led the work. "Our odour-based test detected all nine types of cancer we tested."

Scent of a tumour

Hirotsu and his colleague, Hideto Sonada, decided to investigate roundworms' cancer detecting abilities after Sonada encountered a 63-year-old man with Anisakis larvae in his digestive system. This roundworm can be picked up by eating infected raw fish.

The parasites had attached themselves to a small lesion in the man's stomach that turned out to be the early stages of gastric cancer. The case is one of 29 recorded since 1970 of roundworms attaching themselves to cancers, 62 per cent of which were when the cancer was still in its early stages.

Hirotsu and Sonada's team wondered if the odour of the cancer lesion was attracting the roundworms. To find out, they put droplets of culture medium that cancer cells had grown in on one side of petri dishes. On the other side they put drops of fresh culture medium. When they added C. elegans to the dishes, the worms moved towards the cancer medium.

They grew other kinds of cells in the medium, such as human skin cells, but these induced no such attraction in the worms. The researchers also knocked out the olfactory sense neurons in some of the worms. This stopped them moving towards the cancer side of the dish, suggesting that the worms are indeed attracted by smell.

Sensitive sniffers

To see if they could diagnose cancer, the worms were placed in the vicinity of spots of urine from people with and without cancer. Sure enough, the worms were attracted only to the samples of the people with cancer. With samples taken from 242 people, 24 of whom had a cancer diagnosis, the worms made the correct diagnosis 96 per cent of the time, a success rate that the researchers say is better than any blood test.

The participants had various different types of cancer, and Hirotsu says the worms successfully identified cancer in all nine they were exposed to - stomach, colorectal, colon, oesophageal, pancreas, bile duct, prostate, breast and lung cancer.

The team are now investigating whether different cancer types release different odours, and whether this has an effect on the worms. They hope to have a commercial product ready by 2019. The idea would be that users send a urine sample to the company and get the results back the next day, says Hirotsu.

"It's very surprising that the nematodes exhibited such a strong binary response to 'cancer' versus 'no cancer' urine," says Michael Phillips at Menssana Research, a New Jersey-based company developing diagnostic tests based on people's breath. He says the complexity of the tumours and the environment in which the samples are collected can contribute to confusing results. "We ought to suspend judgement on the test until it has been replicated in other labs using very careful controls," he says.

Journal reference: PlOS One, DOI: 10.1371/journal.pone.0118699

Consciousness on-off switch discovered deep in brain

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ONE moment you're conscious, the next you're not. For the first time, researchers have switched off consciousness by electrically stimulating a single brain area.

Scientists have been probing individual regions of the brain for over a century, exploring their function by zapping them with electricity and temporarily putting them out of action. Despite this, they have never been able to turn off consciousness – until now.

Although only tested in one person, the discovery suggests that a single area – the claustrum – might be integral to combining disparate brain activity into a seamless package of thoughts, sensations and emotions. It takes us a step closer to answering a problem that has confounded scientists and philosophers for millennia – namely how our conscious awareness arises.

Many theories abound but most agree that consciousness has to involve the integration of activity from several brain networks, allowing us to perceive our surroundings as one single unifying experience rather than isolated sensory perceptions.

One proponent of this idea was Francis Crick, a pioneering neuroscientist who earlier in his career had identified the structure of DNA. Just days before he died in July 2004, Crick was working on a paper that suggested our consciousness needs something akin to an orchestra conductor to bind all of our different external and internal perceptions together.

With his colleague Christof Koch, at the Allen Institute for Brain Science in Seattle, he hypothesised that this conductor would need to rapidly integrate information across distinct regions of the brain and bind together information arriving at different times. For example, information about the smell and colour of a rose, its name, and a memory of its relevance, can be bound into one conscious experience of being handed a rose on Valentine's day.

The pair suggested that the claustrum – a thin, sheet-like structure that lies hidden deep inside the brain – is perfectly suited to this job (Philosophical Transactions of The Royal Society B, doi.org/djjw5m).

It now looks as if Crick and Koch were on to something. In a study published last week, Mohamad Koubeissi at the George Washington University in Washington DC and his colleagues describe how they managed to switch a woman's consciousness off and on by stimulating her claustrum. The woman has epilepsy so the team were using deep brain electrodes to record signals from different brain regions to work out where her seizures originate. One electrode was positioned next to the claustrum, an area that had never been stimulated before.

When the team zapped the area with high frequency electrical impulses, the woman lost consciousness. She stopped reading and stared blankly into space, she didn't respond to auditory or visual commands and her breathing slowed. As soon as the stimulation stopped, she immediately regained consciousness with no memory of the event. The same thing happened every time the area was stimulated during two days of experiments (Epilepsy and Behavior, doi.org/tgn).

To confirm that they were affecting the woman's consciousness rather than just her ability to speak or move, the team asked her to repeat the word "house" or snap her fingers before the stimulation began. If the stimulation was disrupting a brain region responsible for movement or language she would have stopped moving or talking almost immediately. Instead, she gradually spoke more quietly or moved less and less until she drifted into unconsciousness. Since there was no sign of epileptic brain activity during or after the stimulation, the team is sure that it wasn't a side effect of a seizure.

Koubeissi thinks that the results do indeed suggest that the claustrum plays a vital role in triggering conscious experience. "I would liken it to a car," he says. "A car on the road has many parts that facilitate its movement – the gas, the transmission, the engine – but there's only one spot where you turn the key and it all switches on and works together. So while consciousness is a complicated process created via many structures and networks – we may have found the key."

Awake but unconscious

Counter-intuitively, Koubeissi's team found that the woman's loss of consciousness was associated with increased synchrony of electrical activity, or brainwaves, in the frontal and parietal regions of the brain that participate in conscious awareness. Although different areas of the brain are thought to synchronise activity to bind different aspects of an experience together, too much synchronisation seems to be bad. The brain can't distinguish one aspect from another, stopping a cohesive experience emerging.

Since similar brainwaves occur during an epileptic seizure, Koubeissi's team now plans to investigate whether lower frequency stimulation of the claustrum could jolt them back to normal. It may even be worth trying for people in a minimally conscious state, he says. "Perhaps we could try to stimulate this region in an attempt to push them out of this state."

Anil Seth, who studies consciousness at the University of Sussex, UK, warns that we have to be cautious when interpreting behaviour from a single case study. The woman was missing part of her hippocampus, which was removed to treat her epilepsy, so she doesn't represent a "normal" brain, he says.

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California must ration water to avoid drought disaster

THE largest state in the US is bone dry, and time is running out to save it. Jay Famiglietti, a hydrologist at NASA's Jet Propulsion Lab and the University of California, Irvine, put out a stark warning last week: start rationing water now to avoid disaster.

Writing in the Los Angeles Times, Famiglietti warned that the state is down to its last year of above-ground reserves, and that its groundwater backup is rapidly disappearing. "California has no contingency plan for a persistent drought like this one," he wrote, "except, apparently, staying in emergency mode and praying for rain." Groundwater is now a primary source of water, as the state experiences its fourth year of severe drought.

California has pumped 15 cubic kilometres out of its main aquifers every year since 2011, according to NASA satellite data. In some places, the ground is sinking at a rate of 30 centimetres a year as a result. No one even knows how the groundwater is being used, as the state has no policies to keep track of it.

Famiglietti also called for the speedier implementation of California's Sustainable Groundwater Management Act, the first law empowering local agencies to regulate and keep account of groundwater extraction. The act requires full sustainability by 2042. "By then, there may be no groundwater left to sustain," he wrote.

This article appeared in print under the headline "California's thirst"

Rights versus bites: The great shark culling debate

Great whites may be behind most attacks around Perth (Image: David Jenkins/Corbis)

Sharks have killed seven people off Western Australia since 2010. Can culling stop them – and what will be the cost to marine wildlife?

EARLIER this year, thousands of protesters gathered at Cottesloe Beach in Perth, Australia. Their message was rather surprising. "Rights, rights, rights for great whites," the crowd chanted. They were demanding an end to shark culling.

The culling – or "localised shark mitigation strategy" as some politicians prefer to call it – was prompted by seven fatal shark attacks off Western Australia since 2010, which led to a fall in tourism and leisure activities. Baited drum lines were used to catch sharks off swimming beaches last summer, with the aim of killing any great white, tiger or bull sharks longer than 3 metres. Others were released if still alive. By the end ...

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Norse legend? The Viking 'GPS' that relied on crystals

How did the Vikings find their way? (Image: Russell Kaye/Sandra-Lee Phipps/Getty)

DURING the Middle Ages, the Vikings set sail in longships to raid settlements and plunder riches, but how did they find their way? They had no magnetic compasses, and the sun and stars would have been obscured on cloudy days and during the long twilight of the northern summer.

According to one suggestion, the answer lies with a special crystal or "sunstone". This, some physicists argue, allowed these seafarers to navigate the north Atlantic by revealing the position of the sun when it was hidden behind clouds, and even after sunset. Yet many archaeologists and historians have serious doubts, pointing to a lack of solid evidence.

It is a debate that doesn't just bear on Viking navigation. It also goes to the heart of what experimental science can and can't contribute to our understanding of the past. ...

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Friday, March 20, 2015

All hail the Anthropocene, the end of Holocene thinking

The Anthropocene geological era is not just the sum of our environmental problems, says Christian Schwägerl. It may also prove to be the age of humility

Read more: Click here to read the original version of this story

What does the term Anthropocene – the proposed name for the geological era we live in – mean to you?
Many view the Anthropocene merely as the sum of all environmental problems. For me it's also the process of becoming aware of our collective responsibility in shaping the future Earth. Can we create a better or even positive geological record that will later tell the story of a planet that regenerated after exploitation?

A paper in Nature last week looked at arguments for an official Anthropocene start date (vol 519, p 171). What feels right to you?
The working group on the Anthropocene – part of the International Union of Geological Sciences – favours a date around 1950, when nuclear explosions and the start of modern consumerism started to have long-term effects on the biosphere.

How should we steer the Anthropocene?
The biggest challenge is to become less anthropocentric: we should stop optimising the planet just for our short-term needs. Our economic system needs to start valuing healthy rainforest and the future inhabitants of Earth. An anthropocentric Anthropocene would be short.

How might we bring about such a change?
I'd like to see new cultural practices arise that express gratitude for what the planet does. Perhaps then in the future things will be totally reversed. Instead of one Earth Day per year, there will be 364. Once a year, we'll have an Anti-Earth Day and allow ourselves to destroy habitats, hunt rare animals, mess with the climate and put toxins in the water.

Do you think this year's climate summit can succeed where the others have failed?
Paris 2015 may be the last chance to agree on global carbon dioxide reductions before there are so many greenhouse gases in the air and the oceans that things get really nasty. To succeed, it would be better not to frame CO₂ reduction as "burden-sharing" any longer, but instead as an opportunity for a prosperous future and as a gigantic call for new R&D in energy, agriculture and materials.

You say we have to end "Holocene thinking". What does that mean?
Holocene thinking rests on the assumption that there is this big, inexhaustible alien space out there that we call the environment, from where we can get our raw materials and food and where we can dump waste. The environment will become the "invironment" in the Anthropocene – something we are deeply connected with.

What can people do to support this vision?
Don't get colonised by destructive industries. Enjoy breathing, eating, being in a forest or a green city space, enjoy helping others, paying attention to the colours and smells and creatures around you. In the Anthropocene we may one day cherish a square metre of wilderness as much as a painting of the same size by Van Gogh or Cézanne.

This article appeared in print under the headline "All hail the Anthropocene"

Profile

Christian Schwägerl is a journalist and biologist and was part of the Anthropocene Project at the House of World Cultures in Berlin, Germany. His latest book is The Anthropocene: The human era and how it shapes our planet (Synergetic Press)

Ancient invaders transformed Britain, but not its DNA

THEY came, they saw, they conquered. But while the Romans, Vikings and Normans ruled Britain for many years, none left their genetic calling cards behind in the DNA of today's mainland Caucasian population. That's the message from the most comprehensive analysis yet of the genetic make-up of the white British population.

The only invaders that left a lasting legacy are the Anglo-Saxons. As well as giving us the English language, the Anglo-Saxons, whose influx began around AD 450, account for 10 to 40 per cent of the DNA in half of modern-day Britons.

The analysis also springs some surprises. There was no single Celtic population outside the Anglo-Saxon dominated areas, but instead a large number of genetically distinct populations (see map below). The DNA signatures of people in the neighbouring counties of Devon and Cornwall are more different than between northern England and Scotland. And there are also unexpectedly stark differences between inhabitants in the north and south of the Welsh county of Pembrokeshire.

The only appreciable genetic input from the Vikings is in the Orkney Islands, which were part of Norway for 600 years. Viking DNA accounts for 25 per cent of today's Orcadian DNA.

The insights come from a study of DNA samples donated by 2039 Caucasian people from around the UK. Each was selected because all four of their grandparents were born within 80 kilometres of each other, allowing the researchers to infer their grandparents' DNA and later link it to a location. Because the grandparents were born on average in 1885, the analysis enabled a genetic snapshot of Caucasian Britain prior to immigrations since then. "Any one person's genome is a random sample of DNA from all four of their grandparents, so it's a way to look back in time," says Peter Donnelly of the Wellcome Trust Centre for Human Genetics in Oxford, UK.

To identify differences between people who have similar genetic make-ups, Donnelly's team searched not just for single genetic alterations, but how common combinations of those alterations were inherited in large chunks of chromosomes. "That's much richer than looking at each genetic difference individually," says Donnelly.

The team found that the genetic profiles of the participants formed 17 distinct clusters. When they mapped this information based on where the participants lived they were surprised to see the clusters mapped almost exactly to geographical location.

The largest cluster accounted for half the participants and occupies almost the whole of eastern and southern England and most of the Midlands. This turned out to be the genetic legacy of the Anglo-Saxon invasions. Even so, at least 60 per cent of the DNA in the cluster had survived from earlier migrants (Nature, DOI: 10.1038/nature14230).

In fact, all 17 clusters are dominated by DNA from settlers that arrived prior to the Anglo-Saxons. By comparing the clusters with genomes from modern-day continental Europe, the team was able to piece together the general migration pattern that took place.

The first wave of arrivals crossed by land bridges, when sea levels were so low that Britain was attached to what is now northern Germany. This wave was dominated by people with genomes most similar to modern-day inhabitants of northern Germany and Belgium. In parallel, migrants from the west coast of France were arriving by boat. Traces of the combined DNA from all these three pioneer settlers forms the basis for the genetic-make up of all white Britons.

Given the cultural significance of the Roman, Viking and Norman invasions, it's surprising they didn't leave greater genetic legacy. For the Romans and Normans, that may be because they were ruling elites who didn't intermarry with the natives.

The overall message is that despite their large cultural impact, Britain's main invaders left no genetic stamp of note. "When you study the past through history, linguistics or archaeology, you learn about successful people," says Donnelly. "History is written by the winners, so much of current historical information is from a relatively small subset of people. Genetics, by contrast, is the history of the masses."

This article appeared in print under the headline "Roman invasion left no genetic legacy"

Correction, 19 March 2015: When this article was first published, a detail on the map was incorrect. This has now been corrected.

Immigration Britain

What have the Romans done for us?

Before the Romans came, Britain was a highly Balkanised cluster of culturally and genetically isolated tribal enclaves. Starting in AD 43, the Romans dissolved many of these barriers in what is now southern and eastern England – partly through building roads. That same area was subsequently occupied by the Anglo-Saxons from AD 450 onwards. Only in the west and north of Britain did the tribes manage to hold on to their isolation, including genetic isolation from the Anglo-Saxons.

Are some regions of Britain inbred?

No. Although some groups are more genetically distinct, they are only subtly so, with a huge amount of commonality across all British Caucasians. It is easier for differences to accumulate and linger in smaller populations, says Donnelly, whereas they become diluted in larger groups.

Are there any medical implications of the findings?

Identification of regional genetic differences means that any harmless regional variants can be ruled out of screenings for disease-related genes. "It makes it easier to distinguish these genetic red herrings," says Donnelly.

Could you do a global version of this genetic study?

Studies on larger populations may be easier as people would be more dissimilar from each other genetically than in a small country like the UK. But the team says it would be really interesting to study individual countries, and a similar study is already in progress in Spain.

Bright spots on Ceres could be water volcanoes

As NASA's Dawn spacecraft pulled into orbit earlier this month around the dwarf planet Ceres in the asteroid belt, it spotted a mysterious bright spot inside a crater. There were suspicions that the spot could be caused by water spewing into space, now fresh views, presented for the first time yesterday, lend weight to the idea.

The pictures show the bright spot is visible even from the side, meaning it probably protrudes above the crater. "What is amazing is you can see this feature while the rim is very likely in front of the line of sight," said Andreas Nathues, who is in charge of the mission's camera, and presented the images yesterday at the Lunar and Planetary Science conference (LPSC) in The Woodlands, Texas. "We believe this could be some kind of outgassing."

Images taken from dusk to dawn on Ceres show that the spot brightens throughout the day and completely disappears at night. This suggests it could be a pocket of ice on the surface that is being heated by the sun and releasing gas, similarly to how a comet behaves. However, Natheus said the team needed higher resolution data to confirm its true nature. This won't come for a while, as Dawn is currently on the dark side of Ceres and won't emerge until mid-April.

Distant observations using the Herschel telescope show Ceres is spitting water from somewhere on its surface, but only Dawn will be able to pinpoint the location. Revealing the origin of Ceres's water could determine whether there is the potential for life beneath its surface, as is thought to be the case on icy moons around Jupiter and Saturn.

But a model of Ceres presented at the LPSC has added a wrinkle by suggesting comet-like behaviour is only possible at the poles of the dwarf planet, not the lower-latitude areas where the bright spot has been seen.

Comet jets and cryo-volcanoes

Timothy Titus of the US Geological Survey in Flagstaff, Arizona, presented a thermal model that examines where on the surface ice could remain stable over the life time of the solar system, rather than boiling away more quickly. If Ceres is acting like a comet, it must have ice patches that can survive for a long time before being heated by the sun as it moves into a warmer part of its orbit.

Titus found that ice could only be stable in regions above 40 degrees latitude. But the plumes spotted by Herschel seemed to come from nearer the equator, which implies they can't be comet-like. "The water ice is just not stable at the latitudes that the plumes are supposedly coming from," Titus says.

Another explanation is cryovolcanism, in which ice and water are forced out of the surface by processes similar to those that drive magma volcanoes on Earth. But according to a second model presented at the LPSC by David O'Brien of the Planetary Science Institute in Tucson, Arizona, Ceres doesn't have enough muscle to drive these eruptions.

Water down deep

The idea is that Ceres has a subsurface ocean covered by an icy shell. As the bottom of the shell freezes, it expands, putting pressure on the ocean and the shell itself. In order to create a cryovolcano, says O'Brien, the water pressure needs to build up enough to launch up through the shell before the ice cracks and relieves the pressure.

We don't know exactly how deep the ice is on Ceres, so O'Brien tried a range of plausible depths. None produced the conditions for spewing cryovolcanoes – the ice always cracked before enough pressure built up. The best case scenario was water reaching about 90 per cent of the way to the surface.

Intriguingly, that means water could potentially reach the surface from a deep crater, where there was less ice to get through – perhaps even from a crater like the one where Dawn saw the bright spot. That doesn't mean there is a cryovolcano producing a massive plume, but it could be just enough to replenish the ice on the surface, countering the instability that Titus discovered.

So Ceres could be producing comet-like emissions in this region, driven by a weak cryovolcano. "It's sort of a midpoint between comets and cryovolcanic icy worlds," says Titus.

There is more than one way to make a cryovolcano, though. Some models suggest the core of Ceres may be heated by radioactive isotopes left over from the dwarf planet's formation. These could provide enough energy for punchier volcanism, perhaps producing larger plumes – and heat would of course be beneficial for any bacteria that may be lurking below the surface. "Any place you've got the potential for liquid water, you've got the potential for life," says Titus. "Ceres could be an extremely exciting astrobiological target."

Video games beat interviews to recruit the very best

Forget interviews. Being good at special video games could land you that plum job – and help make recruitment a fairer process

HATE writing covering letters? Fall to pieces in interviews? Not to worry. Soon the top candidates for a job will be chosen by how well they play video games.

Last week a company called Starfighter was launched. Its aim is to create games you can only master if you have a talent for programming, although those with a natural aptitude can learn as they play. If you do well in a game, the firm knows you are ripe for hiring.

Starfighter's games will have a story. "You'll pretend you're a spy for the day, for example," says Patrick McKenzie, Starfighter's CEO and co-founder. "The story might be to break into tech that's securing state secrets, but it's the same tech you'd use to secure a bank in the real world."

The assumption is that the players who are best at breaking into the software in the game will also be the best at securing it in the real world. Starfighter works with top players to place them in jobs fitting the skills they have demonstrated, if they want them.

The post announcing Starfighter is unequivocal: "Becoming a top Starfighter player is a direct path to receiving lucrative job offers from the best tech companies in the world, because you'll have proven beyond a shadow of a doubt that you can do the work these companies need done."

Starfighter's games will be totally free, and while they won't have fancy graphics, they will be engaging to play just for fun. Starfighter isn't ready to talk about exactly which skills their games will test, but its founders have already built a game called Microcorruption. It imagines a scenario in which players must break into locked warehouses all over the world, each one stuffed with cash. A smartphone app controls each warehouse lock, and the players have to break in without knowing the code. Of 12224 players, just 182 passed the hardest level. The firm will get in touch with these elite players and help place them with one of their clients, who pay Starfighter a fee.

Recruiting new blood through games lets companies search for talented individuals based on more relevant criteria than which college they went to, or what their grades are. But using games has another benefit: it can prevent discrimination.

The benefits of this screening have proved worthwhile in a completely different arena – auditions for professional orchestras. In the 1970s and 1980s, orchestras began to put candidates behind a screen during auditions. Until then just 5 per cent of the players in the top five US orchestras were women. Today, that number is 25 per cent.

Meanwhile Knack, a company based in Palo Alto, California, is developing smartphone games that build up profiles of gamers as they play, measuring things like leadership ability, problem-solving and planning. Those profiles can then be matched with employers looking for similar traits.

"We try to give job recommendations in the same way as Netflix recommends films," says Guy Halfteck, Knack's founder and CEO.

The White House has turned to Knack for Barack Obama's TechHire initiative. The idea is to use Knack's system to help minorities, women and veterans land technology jobs which might normally be closed to them.

Halfteck says Knack has patents that cover inserting its technology into other games, too. This opens up the possibility that gamers who demonstrate high competence in Halo or League of Legends could be recruited right out of their favourite game.

Patrick Gormley of New York-based management consultancy Capco, says his firm is about to start pulling recruits out of Knack's pool of gamers. The firm got its own top-performing project managers to play the games, building profiles that they can then compare with all the players in Knack's system. When the system finds matches, it will send a text telling players they've been matched with a job at Capco, and asking if they want to apply.

"If you're getting a ping you should be very excited," says Halfteck. "It means you're pre-qualified. You are steps ahead of everyone else. You already have potential for success."

This article appeared in print under the headline "Well played, you're hired"

Zoologger: The semaphore 'worms' as big as sperm whales

Video: Giant glowing worm lights up the ocean

Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world

Species: colonies of the genus Pyrosoma
Habitat: open ocean in warm tropical and temperate waters

Ever feel that you're not that coordinated? Just imagine what life would be like if you were part of a giant colony of tiny individuals that all have to do the same thing at the same time.

Huge free-floating coalitions of marine invertebrates known as pyrosomes have to move together to ensure the colony can feed and move in the right direction. They lack any common nerves to communicate, so they may have a different way to move in time – light signalling.

Pyrosomes are made up of hundreds or thousands of clones called zooids. The entire brightly lit colony sprouts from a single individual, and the zooids mesh themselves together as the colony grows outwards in concentric circles from a closed tip to an ever-widening mouth. When the colony is small it looks rather like a butterfly net. As it lengthens, it becomes more like a giant worm that can reach the length of a sperm whale.

The zooids can reproduce by cloning, so the colony can regenerate injured parts and theoretically live forever, shrinking and growing based on available food and physical disturbance.

Huge but invisible

These giant glowing worms can't help but stand out. Yet pyrosomes remain an enigma. With so few people actually having seen them, when a video was posted on a major news site earlier this month saying it was showing pyrosomes, it took several days before anyone spotted that what had really been caught on camera was a mass of squid eggs.

The portraits of pyrosomes are fleshed out with anecdotes. Some divers say that swarms are as soft and delicate as feathers, whereas others claim they are tough enough to ensnare and drown unfortunate penguins.

Why do we see so few of these amazing creatures? According to Mangesh Gauns of India's National Institute of Oceanography in Goa, it is not because pyrosomes are rare.

It is partly because they spend the day in the ocean depths and partly because we're not looking in the right places, he says. Go to the right areas and Gauns is confident that colonies would be abundant.

After analysing the water conditions off the coast of India where a swarm was found, he now thinks he knows what to look for: a combination of cyanobacteria that are small enough for the zooids to swallow along with the right mineral balance in the water. Gauns says these conditions should be commonplace far enough from coastal waters, which are dominated by larger plankton that can block the filter-feeding system of the pyrosomes.

"I am excited to see if we can use these results to get this organism studied more openly," he says.

Light signals

The movement and feeding of the colony is a joint effort and the whole pyrosome is like a giant filtration system. Each zooid sucks in water from outside the colony and blows it out again the other side. This not only feeds them but creates a rudimentary jet engine to give them some control over where they drift to.

Shutting off this propulsion system allows the colony to sink out of harm's way – they regularly dive down to 500-700 metres and have been collected from as far down as 3000 metres. But because they are made up of so many small zooids, coordinating their actions isn't easy. Unpublished research from David Bennett then at Bangor University, UK, offers tentative evidence that this is where a pyrosome's impressive light show comes in.

When a pyrosome is brushed by an external object, it lights up like a Christmas tree – in red or white depending on the species. The signal ripples through the individuals, and they respond by cutting off their engines. Just think of a second world war U-boat film. When the red lights start flashing, it's time to dive.

Journal reference: Zoological Studies, DOI: 10.1186/s40555-014-0075-6

Clucking hell: The nightmare world without chickens

Do we take chickens for granted? (Image: lan Truong)

IF THE world's cats and dogs disappeared overnight, millions of people would mourn their furry friends. If beef cattle suddenly ceased to exist, it would create economic crises in America, Argentina and Australia. But what if all of Earth's 22 billion chickens succumbed to a scourge like bird flu? How would humanity cope?

It's a thought experiment whose answers show just how much human civilisation has come to rely on a single species. Without chickens, we would face "a starving world", says Olivier Hanotte, a molecular biologist at the University of Nottingham, UK, who has studied the spread of the chicken around the globe. Close to one-third of the world's meat supply and nearly all of its eggs would vanish. Pandemics and riots could ensue, unleashing a crisis of enormous proportions. This might seem far-fetched given how unremarkable ...

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Thursday, March 19, 2015

Chermoula tofu and roasted vegetables

Ingredients

To chermoula tofu

25 g / 1 oz finely chopped cilantro

3 cloves garlic, minced

1 teaspoon cumin seeds, lightly crushed

1 lemon, finely grated zest

½ tsp dried chilli flakes

1 tablespoon olive oil

250g / 9 oz tofu

For the roasted vegetables

2 red onions, quartered

2 zucchini, cut into thick slices

2 red peppers, seeded and sliced

2 yellow peppers, seeded and sliced

1 small eggplant, cut into thick slices

low calorie cooking spray

pinch of salt

Method of Preparation

Preheat oven to 200C / 180C Fan / Gas 6.

To chermoula, combine the cilantro, garlic, cumin, lemon zest and pepper with olive oil and a little salt in a small bowl.

Pat the tofu dry on kitchen paper and cut it in half. Cut each half horizontally into thin slices. Spread generously chermoula at the edges.

Spread the vegetables in a roasting pan and drizzle with oil. Bake for about 45 minutes, until lightly browned, turning once or twice during cooking ingredients.

Place tofu slices on vehicles, side propagation of the highest chermoula and cook for 10-15 minutes, or until tofu is lightly colored.

Divide the tofu and vegetables among four plates and serve.