Category: Living World

Phosphorus Is Vital for Life, and We’re Running Low

By Vera Thoss, Bangor University | March 15, 2017 11:05 am
phosphorus

A farmer sprays field with a nitrogen, phosphorus, potassium fertilizer. (Credit: oticki/Shutterstock)

All life needs phosphorus and agricultural yields are improved when phosphorus is added to growing plants and the diet of livestock. Consequently, it is used globally as a fertilizer – and plays an important role in meeting the world’s food requirements.

In order for us to add it, however, we first need to extract it from a concentrated form – and the supply comes almost exclusively from phosphate mines in Morocco (with far smaller quantities coming from China, the US, Jordan and South Africa). Within Morocco, most of the mines are in Western Sahara, a former Spanish colony which was annexed by Morocco in 1975.

The fact that more than 70 percent of the global supply comes from this single location is problematic, especially as scientists are warning that we are approaching “peak phosphorus”, the point at which demand begins to outstrip supply and intensive agriculture cannot continue to provide current yields. In the worst case scenario, mineable reserves could be exhausted within as little as 35 years.

So what is going on – and how worried should be?

Here be phosphorus. (Credit: Shutterstock)

Natural Limits

In nature, phosphorus only exists bound to oxygen, which is called phosphate. It is in this form that it is mined. Chemists can remove the oxygens bound to it to get elemental white phosphorus, which glows in the dark, but it is so unstable that it spontaneously ignites on exposure to air.

Phosphate easily diffuses through soil or water and can be taken up by cells. When phosphate meets free calcium or iron, they combine to give highly insoluble salts.

In the first half of the 19th century, Justus von Liebig popularized the law of the minimum for agriculture, which states that growth is limited by the least available resource. It was soon discovered that this was often some form of phosphorus.

As a consequence, bones – comprised mostly of calcium and phosphate – from old battlefields were dug up to use in farming. Guano, large accumulations of bird droppings, also contains high concentrations of phosphorus and was used to fertilize crops. But supplies of this were soon depleted. As demand increased, supplies had to be mined instead.

But this applied inorganic phosphate fertilizer is highly mobile and leaches into watercourses. In addition, phosphate rock weathers and is also ultimately washed into the ocean where it either deposits as calcium phosphate or is taken up by marine organisms who also eventually deposit on the ocean floor when they die. Consequently, terrestrial phosphorus doesn’t really disappear, but it can move beyond our reach.

Natural Wastage

To complicate matters further, even the phosphorus we can use is largely wasted. Of the phosphorus mined as fertilizer, only a fifth reaches the food we eat. Some leaches away and some is bound to calcium and iron in the soil. Some plant roots have the ability to extract the latter, but not in large enough quantities to retrieve all of it.

In addition to these inorganic forms, phosphate is also converted into cellular compounds, creating organically-bound phosphorus, such as phospholipids or phytate. After the death of an organism, these organic phosphorus compounds need to be returned into the useable phosphate form. How much organically-bound phosphorus is present in soils depends on the number and activity of the organisms that can do this.

Phosphorous boosts crop yields. (Credit: Shutterstock)

Agricultural soils are usually rich in inorganic phosphorus while in undisturbed ecosystems, such as forests and long-term pastures, organically-bound phosphorus dominates. But agricultural land is often depleted of phosphorus during harvest and land management practices such as ploughing, hence the addition of phosphate-containing fertilizers.

Spreading manure and avoiding tillage are ways of increasing microbial abundance in the soil – and so keeping more phosphorus in an organically-bound form.

The risks of peak phosphorus can be countered with some simple solutions. Eating less meat is a start as huge amounts are used to rear livestock for meat. The chances are that agricultural yields are limited by phosphorus availability and will be further stretched as the global population grows.

Humans are themselves wasteful of phosphorus, as most of what we take in goes straight out again. Fortunately, technologies have been developed to mine phosphorus from sewage, but at present are too expensive to be practical.

Peak phosphorus does not mean that phosphorus will disappear, rather that the reserves with mineable high concentrations are depleting. Instead, we are increasing the background concentrations of phosphorus and adding it to the ocean floor. More sustainable phosphorus use requires a greater appreciation and understanding of the many organisms that make up soils – and the part they play in phosphorus distribution – or we may no longer be able to feed the world at an affordable price.

 

This article was originally published on The Conversation. Read the original article.

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: chemistry

The Frog Tongue’s Sticky Secrets Revealed

frog_fly

(Credit: Shutterstock)

How does one get stuck studying frog tongues? Our study into the sticky, slimy world of frogs all began with a humorous video of a real African bullfrog lunging at fake insects in a mobile game. This frog was clearly an expert at gaming; the speed and accuracy of its tongue could rival the thumbs of texting teenagers. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: animals

The Underrated Genius of Neanderthals

By Stephen E. Nash | January 24, 2017 4:43 pm
caveman

Geico’s “so easy a caveman can do it” advertising campaign incorrectly minimized the intelligence of Neanderthals. (Credit: Shutterstock)

(This post originally appeared in the online anthropology magazine SAPIENS. Follow @SAPIENS_org on Twitter to discover more of their work.) 

For the last dozen years or so, Geico Insurance has run commercials featuring Neanderthals in modern contexts. The story line varies, but the take-home point does not: Switching to Geico is so easy that “even a caveman can do it,” says the tag line. The Neanderthal’s feelings are invariably hurt, and a stereotype gets perpetuated. Do Neanderthals really deserve such derision?

Popularly known as “cavemen,” Neanderthals were ancestral humans who lived in Western Europe, on the eastern shores of the Mediterranean, and in southwestern and central Asia from about 400,000 to 40,000 years ago. They lived in glacial environments during the Ice Age as well as in warmer time periods. Their foreheads were low and receding in contrast to the high, almost vertical foreheads of modern humans. They also had protruding faces and heavy brow ridges above their eyes. While it’s an open question whether you’d recognize a Neanderthal if you saw one on the street, groomed and dressed in modern clothes, I like to think they’d blend in at my museum’s holiday party. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: archaeology

Is Cloud Seeding Worth the Bet?

By Ian Graber-Stiehl | January 24, 2017 1:10 pm
cloud-seeding-aircraft

Pilots from Weather Modification, Inc., prepare the cloud seeding aircraft with seeding flares. (Credit: Derek Blestrud, Idaho Power Company)

“Make mud, not war.” That was the slogan of the American 54th Weather Reconnaissance Squad, the first military force to engage in weather warfare.

Throughout the Vietnam War, they flew 2,602 missions, releasing silver iodide, a compound that seeded clouds and exacerbated monsoons—or so the thinking went. Dubbed “Operation Popeye”, this rainy warfare would last from 1966-72, until banned under the 1977 Enmod Treaty on weather warfare. Popeye wasn’t the only attempt to weaponize seasonal events, but it was the most infamous. There was also, for example, an “exercise” aiming to make the Hồ Chí Minh trail muddier, named “Commando Lava”. The problem with infamy, however, is that the subjects of it rarely live up to the legend. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: earth science, weather

Pew! Pew! Paleontologists Harness the Power of Lasers

By Jon Tennant | December 20, 2016 12:38 pm

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When in possession of a priceless dinosaur skeleton, it’s always a good idea to fire a super-charged photon beam at it.

That’s Thomas G. Kaye’s philosophy: if you can fossilize it, you can fire a laser at it. Kaye, of the Foundation of Scientific Advancement, Sierra Vista, developed a laser-scanning technique that reveals stunning new details buried within dinosaur fossils — so meta. Now he’s traveling the world placing new specimens in his crosshairs.

Kaye is joined by Mike Pittman, who’s already infamous at Discover for spotting fossils while taking a whiz in the Gobi Desert. Together, they’re trekking around the world armed with nothing more than their portable laser and an inquisitive eye. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: paleontology

A History Recalled, One Symbol at a Time

By Stephen E. Nash | December 7, 2016 11:46 am
Denver Museum of Nature & Science

The spiraling story of the Chief Martin White Horse Winter Count documents significant events in Lakota history each year from 1789 to 1910. (Credit: AC.7923/DMNS)

(This post originally appeared in the online anthropology magazine SAPIENS. Follow @SAPIENS_org on Twitter to discover more of their work.) 

Time. Astronomers, philosophers, physicists, anthropologists, politicians, geographers, and theologians have all pondered the nature and meaning of time. Is it linear or cyclical? Is it reversible? (Put another way, can we go back in time?) Is time absolute and measurable, as it seemed to be to Isaac Newton and Galileo Galilei, or is it relative, as Albert Einstein theorized? Cynically, is it “what keeps everything from happening at once,” as science fiction author Ray Cummings wrote so memorably in 1923? Is time a cultural construct? Or is it a corollary to the second law of thermodynamics, under which disorder always increases? Why does time seem to go so much faster the older we get? Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: anthropology

British Squirrels Are Suffering from Leprosy

By Stephen Harrison, Nottingham Trent University | November 11, 2016 1:58 pm
red-squirrel

A red squirrel. (Credit: Shutterstock)

For many people, leprosy brings to mind Biblical stories of diseased people cast out from society. It’s a condition that today is largely found in developing countries, whereas in other, mostly Western nations it’s a pestilence of the past that was eradicated decades ago. But recent research has shown the disease not only persists in Britain but, perhaps more alarmingly, is also being carried by one of our best loved and most endangered native mammals, the red squirrel.

The study by researchers at the University of Edinburgh and EPFL in Switzerland found red squirrels from England, Scotland and Ireland were infected with leprosy. In particular, a group from Brownsea Island on the south coast of England had a strain of the disease virtually identical to one that infected humans in the middle ages. Read More

Is It Time for Medicine to Ditch Lab Mice?

By Nathaniel Scharping | November 1, 2016 12:13 pm
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(Credit: Shutterstock)

“Cancer has been cured a thousand times.”

So says Christopher Austin, the director of the National Center for Advancing Translational Sciences (NCATS) at the National Institutes of Health. Austin should know — as the director of NCATS, his focus is on exactly these kinds of groundbreaking laboratory studies.

His proclamation comes with a significant caveat that will pop the bubbles in your champagne. Austin is so interested in these studies because they all happened in mice, in a lab. When the hundreds of different drugs that made mouse tumors disappear were carried forward to human trials, they went in and came out without doing what they promised. Or worse, they turned out to be toxic. Read More

Sherlock Holmes, Spirit Hunting and a Great Hoax

By David Warmflash | October 31, 2016 12:56 pm
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Sir Arthur Conan Doyle was a revered author and physician, but he was an ardent proponent of spiritualism during his lifetime. (Credit: The British Library)

Back in August, it seemed that Sir Arthur Conan Doyle, the creator of Sherlock Holmes, was cleared of playing any role in one of the greatest hoaxes in scientific history. But in true Sherlockian form, there may still be a twist in this case that appears to be closed. And it’s a fitting discussion on Halloween.

The infamous ‘Piltdown Man’ hoax culminated in 1912 after esteemed geologist Sir Arthur Smith Woodward and amateur archaeologist Charles Dawson announced they had discovered the ‘missing link’ between ape and man. It featured a human-sized skull with an ape-like jaw, and it fooled scientists for 40 years before it was debunked.

So how did Conan Doyle get involved in this, and why should he still remain on the suspect list, despite the latest evidence? Stay with me as I dig deeper into this longstanding controversy.  Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: archaeology

Can Science Save the Banana?

(Credit: Shutterstock)

(Credit: Shutterstock)

The banana is the world’s most popular fruit crop, with over 100 million metric tons produced annually in over 130 tropical and subtropical countries. Edible bananas are the result of a genetic accident in nature that created the seedless fruit we enjoy today. Virtually all the bananas sold across the Western world belong to the so-called Cavendish subgroup of the species and are genetically nearly identical. These bananas are sterile and dependent on propagation via cloning, either by using suckers and cuttings taken from the underground stem or through modern tissue culture.

The familiar bright yellow Cavendish banana is ubiquitous in supermarkets and fruit bowls, but it is in imminent danger. The vast worldwide monoculture of genetically identical plants leaves the Cavendish intensely vulnerable to disease outbreaks. Fungal diseases severely devastated the banana industry once in history and it could soon happen again if we do not resolve the cause of these problems. Plant scientists, including us, are working out the genetics of wild banana varieties and banana pathogens as we try to prevent a Cavendish crash. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: agriculture
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