Category Archives: Life

The depletion of the human microbiome and how it can be restored

Tobias Rees and Nils Gilman write:

It is a crisis some scientists believe has similar proportions to climate change, but it gets much less coverage: Microbes are disappearing from our bodies.

You may have heard that trillions of microbes — bacteria, fungi, viruses, protists — live on every surface of your body as well as inside your mouth, other orifices and your gut. You may have also heard that these microbes make up the majority of your body’s cells.

But few are aware of how directly these microbes and their genes affect the functioning of our bodies. The human genome found in the nuclei of our cells contains roughly 20,000 genes, but the microbiome — the sum total of genetic material in the microorganisms that live in and on us — contains as many as 20 million genes, all of which are directly or indirectly interacting with and at times even controlling our genes.

Our microbial genes are critical to the regulation of our metabolism, to the ability of our immune system to fight off infection and to the production of the neurotransmitters that power our brain and nervous system. The microbiome, just like our nuclear genome, is heritable. The majority of microbes are transferred from mother to child during childbirth, in a chain of transmission that reaches back to the earliest animals that evolved — which happen to have been microbes.

So why the crisis? [Continue reading at my new site: Attention to the Unseen]

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Inspired by ISIS: Trump administration will reward hunters who collect severed heads as ‘trophies’

If there’s any remaining doubt that the U.S. government is now led by a cabal of twisted misfits, read this:

Wayne Pacelle, President and CEO of The Humane Society of the United States, writes: With barely contained enthusiasm, Safari Club International (SCI) announced on its own initiative today that the U.S. Fish and Wildlife Service (FWS) has reversed critical elephant protections established during the Obama administration, allowing imports of elephant trophies from Zimbabwe and Zambia. For decades, Zimbabwe has been run by a dictator who has targeted and killed his political opponents, and operated the country’s wildlife management program as something of a live auction. Remember, it was Zimbabwe where Walter Palmer shot Cecil, one of the most beloved and well-studied African lions, who was lured out of a national park for the killing. Palmer paid a big fee even though it did irreparable damage to the nation’s reputation.

The United States has listed African elephants under the federal Endangered Species Act, and hunting trophies can only be imported if the federal government finds that killing them positively enhances the survival of the species. Under the prior administration, FWS made the eminently reasonable decision that Zimbabwe – one of the most corrupt countries on earth – was not managing its elephant population in a sustainable manner. Government officials allegedly have been involved in both poaching of elephants and illegal export of ivory tusks. Zimbabwean President Robert Mugabe even celebrated his birthday last year by feasting on an elephant.

Zimbabwe’s elephant population has declined six percent since 2001 and evidence shows that poaching has increased in areas where trophy hunting is permitted (such as in the Chirisa and Chete safari areas). A number of problems with Zimbabwe’s elephant management remain unresolved to date: the lack of an elephant management plan; lack of sufficient data on population numbers and trends; anemic enforcement of wildlife laws; lack of information about how money derived from trophy hunting by U.S. hunters is distributed within Zimbabwe; and lack of a national mechanism, such as government support, to sustain elephant conservation efforts in the country.

This jarring announcement comes on the same day that global news sources report that Mr. Mugabe, Zimbabwe’s aging dictator, is under house arrest following a military coup. This fact in and of itself highlights the absurdity and illegal nature of the FWS decision to find that Zimbabwe is capable of ensuring that elephant conservation and trophy hunting are properly managed. [Continue reading…]

Given its passion for violence and destruction, ISIS has often been described as a nihilistic movement. Likewise, men who confuse the destructive power of weapons with a measure of their own strength are also unleashing a life-denying nihilistic force. This might get cloaked in some childish mythology about the return to a natural state in which man fights for his own survival, but if any hunter truly wanted to understand what that might actually mean, they should find out what it’s like to live for a while among one of the few remaining tribes of hunter-gatherers. Most likely, the big game hunters who want to proudly display an elephant or lion’s head above their mantelpiece, wouldn’t have enough stamina to trek for hours on end through savannah or jungle, let alone have the skill to participate in a kill.

Walter Palmer later said: “If I had known this lion had a name and was important to the country or a study, obviously I wouldn’t have taken it. Nobody in our hunting party knew before or after the name of this lion.”

Presumably, in his way of thinking, the creatures of particular value get names while the rest are expendable — a perspective that no doubt applies not just among hunters but among employers and across many sectors of human society.

If the protection of endangered species requires that surviving individuals all get named, we will soon end up in a situation where these animals can only be found in zoos and viable gene pools will have been decimated along with the habitats that sustain species diversity.

Those who believe they can pick and choose between lives, designating a few as precious and many others as worthless, really need to ask themselves whether they value life at all.

At the root of this assumption of a god-like power over life, there is an expression of alienation from life itself.

Those who destroy or neglect the lives of others, far from ensuring their own survival, have on the contrary lost touch with the vibrant experience of what it means to be alive. Life is not something we can possess but something by which we are possessed.

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The physics of life

Jeremy England writes: Living things are so impressive that they’ve earned their own branch of the natural sciences, called biology. From the perspective of a physicist, though, life isn’t different from non-life in any fundamental sense. Rocks and trees, cities and jungles, are all just collections of matter that move and change shape over time while exchanging energy with their surroundings. Does that mean physics has nothing to tell us about what life is and when it will appear? Or should we look forward to the day that an equation will finally leap off the page like a mathematical Frankenstein’s monster, and say, once and for all, that this is what it takes to make something live and breathe?

As a physicist, I prefer to chart a course between reductionism and defeat by thinking about the probability of matter becoming more life-like. The starting point is to see that there are many separate behaviours that seem to distinguish living things. They harvest energy from their surroundings and use it as fuel to make copies of themselves, for example. They also sense, and even predict things about the world they live in. Each of these behaviours is distinctive, yes, but also limited enough to be able to conceive of a non-living thing that accomplishes the same task. Although fire is not alive, it might be called a primitive self-replicator that ‘copies’ itself by spreading. Now the question becomes: can physics improve our understanding of these life-like behaviours? And, more intriguingly, can it tell us when and under what conditions we should expect them to emerge?

Increasingly, there’s reason to hope the answer might be yes. The theoretical research I do with my colleagues tries to comprehend a new aspect of life’s evolution by thinking of it in thermodynamic terms. When we conceive of an organism as just a bunch of molecules, which energy flows into, through and out of, we can use this information to build a probabilistic model of its behaviour. From this perspective, the extraordinary abilities of living things might turn out to be extreme outcomes of a much more widespread process going on all over the place, from turbulent fluids to vibrating crystals – a process by which dynamic, energy-consuming structures become fine-tuned or adapted to their environments. Far from being a freak event, finding something akin to evolving lifeforms might be quite likely in the kind of universe we inhabit – especially if we know how to look for it. [Continue reading…]

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A giant insect ecosystem is collapsing due to humans. It’s a catastrophe

Michael McCarthy writes: Thirty-five years ago an American biologist Terry Erwin conducted an experiment to count insect species. Using an insecticide “fog”, he managed to extract all the small living things in the canopies of 19 individuals of one species of tropical tree, Luehea seemannii, in the rainforest of Panama. He recorded about 1,200 separate species, nearly all of them coleoptera (beetles) and many new to science; and he estimated that 163 of these would be found on Luehea seemannii only.

He calculated that as there are about 50,000 species of tropical tree, if that figure of 163 was typical for all the other trees, there would be more than eight million species, just of beetles, in the tropical rainforest canopy; and as beetles make up about 40% of all the arthropods, the grouping that contains the insects and the other creepy-crawlies from spiders to millipedes, the total number of such species in the canopy might be 20 million; and as he estimated the canopy fauna to be separate from, and twice as rich as, the forest floor, for the tropical forest as a whole the number of species might be 30 million.

Yes, 30 million. It was one of those extraordinary calculations, like Edwin Hubble’s of the true size of the universe, which sometimes stop us in our tracks.

Erwin reported that he was shocked by his conclusions and entomologists have argued over them ever since. But about insects, his findings make two things indisputably clear. One is that there are many, many more types than the million or so hitherto described by science, and probably many more than the 10m species sometimes postulated as an uppermost figure; and the second is that this is far and away the most successful group of creatures the Earth has ever seen.

They are multitudinous almost beyond our imagining. They thrive in soil, water, and air; they have triumphed for hundreds of millions of years in every continent bar Antarctica, in every habitat but the ocean. And it is their success – staggering, unparalleled and seemingly endless – which makes all the more alarming the great truth now dawning upon us: insects as a group are in terrible trouble and the remorselessly expanding human enterprise has become too much, even for them.

Does it matter? Oh yes. Most of our fruit crops are insect-pollinated, as are the vast majority of our wild plants
The astonishing report highlighted in the Guardian, that the biomass of flying insects in Germany has dropped by three quarters since 1989, threatening an “ecological Armageddon”, is the starkest warning yet; but it is only the latest in a series of studies which in the last five years have finally brought to public attention the real scale of the problem. [Continue reading…]

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Insectageddon: Farming is more catastrophic than climate breakdown

George Monbiot writes: Which of these would you name as the world’s most pressing environmental issue? Climate breakdown, air pollution, water loss, plastic waste or urban expansion? My answer is none of the above. Almost incredibly, I believe that climate breakdown takes third place, behind two issues that receive only a fraction of the attention.

This is not to downgrade the danger presented by global heating – on the contrary, it presents an existential threat. It is simply that I have come to realise that two other issues have such huge and immediate impacts that they push even this great predicament into third place.

One is industrial fishing, which, all over the blue planet, is now causing systemic ecological collapse. The other is the erasure of non-human life from the land by farming.

And perhaps not only non-human life. According to the UN Food and Agriculture Organisation, at current rates of soil loss, driven largely by poor farming practice, we have just 60 years of harvests left. And this is before the Global Land Outlook report, published in September, found that productivity is already declining on 20% of the world’s cropland.

The impact on wildlife of changes in farming practice (and the expansion of the farmed area) is so rapid and severe that it is hard to get your head round the scale of what is happening. A study published this week in the journal Plos One reveals that flying insects surveyed on nature reserves in Germany have declined by 76% in 27 years. The most likely cause of this Insectageddon is that the land surrounding those reserves has become hostile to them: the volume of pesticides and the destruction of habitat have turned farmland into a wildlife desert.

It is remarkable that we need to rely on a study in Germany to see what is likely to have been happening worldwide: long-term surveys of this kind simply do not exist elsewhere. This failure reflects distorted priorities in the funding of science. There is no end of grants for research on how to kill insects, but hardly any money for discovering what the impacts of this killing might be. Instead, the work has been left – as in the German case – to recordings by amateur naturalists.

But anyone of my generation (ie in the second bloom of youth) can see and feel the change. We remember the “moth snowstorm” that filled the headlight beams of our parents’ cars on summer nights (memorialised in Michael McCarthy’s lovely book of that name). Every year I collected dozens of species of caterpillars and watched them grow and pupate and hatch. This year I tried to find some caterpillars for my children to raise. I spent the whole summer looking and, aside from the cabbage whites on our broccoli plants, found nothing in the wild but one garden tiger larva. Yes, one caterpillar in one year. I could scarcely believe what I was seeing – or rather, not seeing.

Insects, of course, are critical to the survival of the rest of the living world. Knowing what we now know, there is nothing surprising about the calamitous decline of insect-eating birds. Those flying insects – not just bees and hoverflies but species of many different families – are the pollinators without which a vast tract of the plant kingdom, both wild and cultivated, cannot survive. The wonders of the living planet are vanishing before our eyes. [Continue reading…]

Out of sight, out of mind — the issue here is not just generational in the sense experienced by those of us old enough to remember insects, birds, and other creatures in greater numbers. The issue is above all one that springs from the physical separation between humans and nature in a world where humans experience life predominantly inside cities and predominantly as the seemingly most commonplace species.

I happen to live in a town where squirrels undoubtedly outnumber humans and where bears can show up in the most unexpected places and yet even here, for most people most of the time, nature remains in the background of human affairs.

While the rapid demise of flying insects should provoke alarm in anyone with even just a rudimentary understanding of the interdependence of species, a more commonplace response is likely to be that this loss signifies a welcome reduction in unwanted pests — fewer mosquitoes, fewer flies, and less irritants to complain about.

When it comes to human appreciation for non-human forms of life, insects get short shrift.

Butterflies are admired and yet most people would be hard pressed to name a single species, let alone recognize and appreciate any species in its larval form.

Bees are appreciated as productive, yet potentially dangerous and to most people indistinguishable from wasps.

Ants are lauded in the abstract as exemplars of industry and complex social organization and yet bound to suffer swift extermination when they turn up where they’re unwelcome.

Even so, the objective truth that insects would grasp if they had the cognitive capacities to do so is that the most prolific forms of life that have lived sustainably on this planet for hundreds of millions of years are now at risk from the life-threatening effects of human infestation.

No, this isn’t an argument for the elimination of humans, but as the late-comers on the stage of life, we have to do a hell of a lot better learning how to harmoniously co-exist with the creatures around us. Not only do their lives depend on this, but so do ours.

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Warning of ‘ecological Armageddon’ after dramatic plunge in insect numbers

The Guardian reports: The abundance of flying insects has plunged by three-quarters over the past 25 years, according to a new study that has shocked scientists.

Insects are an integral part of life on Earth as both pollinators and prey for other wildlife and it was known that some species such as butterflies were declining. But the newly revealed scale of the losses to all insects has prompted warnings that the world is “on course for ecological Armageddon”, with profound impacts on human society.

The new data was gathered in nature reserves across Germany but has implications for all landscapes dominated by agriculture, the researchers said.

The cause of the huge decline is as yet unclear, although the destruction of wild areas and widespread use of pesticides are the most likely factors and climate change may play a role. The scientists were able to rule out weather and changes to landscape in the reserves as causes, but data on pesticide levels has not been collected.

“The fact that the number of flying insects is decreasing at such a high rate in such a large area is an alarming discovery,” said Hans de Kroon, at Radboud University in the Netherlands and who led the new research.

“Insects make up about two-thirds of all life on Earth [but] there has been some kind of horrific decline,” said Prof Dave Goulson of Sussex University, UK, and part of the team behind the new study. “We appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon. If we lose the insects then everything is going to collapse.” [Continue reading…]

I often get the impression that many of the people who dismiss dire warnings about environmental collapse and climate change have a fabulously inflated faith in the human capacity to solve problems through technical solutions, combined with an attitude that the natural world is in some fundamental sense superfluous to human needs. Seemingly, nature needs protecting mostly because it provides pleasant locations for vacations.

Nevertheless, experiments in the creation of closed ecological systems should have already shattered any illusions about the capacity for humanity to survive on an ecologically wrecked planet through artificial means.

But maybe the cavalier attitude that many decision-makers display in the exercise of their responsibility to protect the ecosystem on which all of life depends is ultimately a reflection of the cynicism and selfishness of individuals who simply don’t care much about the continuation of life after the end of their own.

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How toxic PCBs came to permeate life on Earth

Rebecca Altman writes: Deep in the Mariana Trench, at depths lower than the Rockies are high, rests a tin of reduced-sodium Spam.

NOAA scientists caught sight of it last year near the mouth of the Mariana’s Sirena Deep. It isn’t an isolated incursion, but it was nevertheless startling, the sight of those timeless golden letters bright against the deep ocean bottom.

Shortly after came news from another team of scientists who had found in the Mariana an innovation less familiar than shelf-stable meat, but far more significant. In the bodies of deep-dwelling creatures were found traces of industrial chemicals responsible for the rise of modern America—polychlorinated biphenyls.

PCBs had been detected in Hirondellea gigas, tiny shrimp-like amphipods scooped up by deepwater trawlers. Results from the expedition, led by Newcastle University’s hadal-zone expert Alan Jamieson, were preliminary released last year and then published in February.

PCBs have been found the world over—from the bed of the Hudson River to the fat of polar bears roaming the high Arctic—but never before in the creatures of the extreme deep, a bioregion about which science knows relatively little.

How PCBs reached the Mariana is still under investigation. Jamieson and colleagues speculated on multiple, regional sources. A nearby military base. The industrial corridors along the Asian coastline. And the Great Pacific Garbage Patch, where PCBs glom onto plastic particles caught in the current. Over time, the plastic degrades and descends into the depths, ferrying PCBs with them.

But the true origin of PCBs lies in another time and place, in Depression-era Alabama, and before that, 19th-century Germany at the pinnacle of German chemistry. [Continue reading…]

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In his journal, Thoreau discovered how to balance poetic wonder and scientific rigor

Andrea Wulf writes: In late 1849, two years after Henry David Thoreau left Walden Pond—where he had lived for two years, two months, and two days in a cabin that he had built himself—he began the process of completely reorienting his life again. His hermit-style interlude at the pond had attracted quite a bit of attention in his hometown of Concord, Massachusetts. “Living alone on the pond in ostentatious simplicity, right in sight of a main road,” his latest biographer, Laura Dassow Walls, writes, “he became a spectacle,” admired by some and belittled by others. Thoreau’s subsequent life change was less conspicuous. Yet it engaged him in a quest more enlightening and relevant today than the proud asceticism he flaunted throughout Walden, a book that has never ceased to inspire reverence or provoke contempt.

What the 32-year-old Thoreau quietly did in the fall of 1849 was to set up a new and systematic daily regimen. In the afternoons, he went on long walks, equipped with an array of instruments: his hat for specimen-collecting, a heavy book to press plants, a spyglass to watch birds, his walking stick to take measurements, and small scraps of paper for jotting down notes. Mornings and evenings were now dedicated to serious study, including reading scientific books such as those by the German explorer and visionary thinker Alexander von Humboldt, whose Cosmos (the first volume was published in 1845) had become an international best seller.

As important, Thoreau began to use his own observations in a new way, intensifying and expanding the journal writing that he’d undertaken shortly after graduating from Harvard in 1837, apparently at Ralph Waldo Emerson’s suggestion. In the evening, he often transferred the notes from his walks into his journal, and for the rest of his life, he created long entries on the natural world in and around Concord. Thoreau was staking out a new purpose: to create a continuous, meticulous documentary record of his forays. Especially pertinent two centuries after his birth, in an era haunted by inaction on climate change, he worried over a problem that felt personal but was also spiritual and political: how to be a rigorous scientist and a poet, imaginatively connected to the vast web of natural life. [Continue reading…]

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Microbes that eat electricity

Emily Singer writes: [In 2015], biophysicist Moh El-Naggar and his graduate student Yamini Jangir plunged beneath South Dakota’s Black Hills into an old gold mine that is now more famous as a home to a dark matter detector. Unlike most scientists who make pilgrimages to the Black Hills these days, El-Naggar and Jangir weren’t there to hunt for subatomic particles. They came in search of life.

In the darkness found a mile underground, the pair traversed the mine’s network of passages in search of a rusty metal pipe. They siphoned some of the pipe’s ancient water, directed it into a vessel, and inserted a variety of electrodes. They hoped the current would lure their prey, a little-studied microbe that can live off pure electricity.

The electricity-eating microbes that the researchers were hunting for belong to a larger class of organisms that scientists are only beginning to understand. They inhabit largely uncharted worlds: the bubbling cauldrons of deep sea vents; mineral-rich veins deep beneath the planet’s surface; ocean sediments just a few inches below the deep seafloor. The microbes represent a segment of life that has been largely ignored, in part because their strange habitats make them incredibly difficult to grow in the lab.

Yet early surveys suggest a potential microbial bounty. A recent sampling of microbes collected from the seafloor near Catalina Island, off the coast of Southern California, uncovered a surprising variety of microbes that consume or shed electrons by eating or breathing minerals or metals. El-Naggar’s team is still analyzing their gold mine data, but he says that their initial results echo the Catalina findings. Thus far, whenever scientists search for these electron eaters in the right locations — places that have lots of minerals but not a lot of oxygen — they find them. [Continue reading…]

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The stunning underwater picture this photographer wishes ‘didn’t exist’

Lindsey Bever writes: The powerful and poignant image shows a tiny sea horse holding tightly onto a pink, plastic cotton swab in blue-green waters around Indonesia.

California nature photographer Justin Hofman snapped the picture late last year off the coast of Sumbawa, an Indonesian island in the Lesser Sunda Islands chain. The 33-year-old, from Monterey, Calif., said a colleague pointed out the pocket-size sea creature, which he estimated to be about 1.5 inches tall — so small, in fact, that Hofman said he almost didn’t reach for his camera.

“The wind started to pick up and the sea horse started to drift. It first grabbed onto a piece of sea grass,” Hofman said Thursday in a phone interview.

Hofman started shooting.

“Eventually more and more trash and debris started to move through,” he said, adding that the critter lost its grip, then latched onto a white, wispy piece of a plastic bag. “The next thing it grabbed was a Q-Tip.”

Hofman said he wishes the picture “didn’t exist” — but it does; and now, he said, he feels responsible “to make sure it gets to as many eyes as possible.” [Continue reading…]

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This is how our world could end

Peter Brannen writes: Many of us share some dim apprehension that the world is flying out of control, that the centre cannot hold. Raging wildfires, once-in-1,000-years storms and lethal heatwaves have become fixtures of the evening news – and all this after the planet has warmed by less than 1C above preindustrial temperatures. But here’s where it gets really scary.

If humanity burns through all its fossil fuel reserves, there is the potential to warm the planet by as much as 18C and raise sea levels by hundreds of feet. This is a warming spike of an even greater magnitude than that so far measured for the end-Permian mass extinction. If the worst-case scenarios come to pass, today’s modestly menacing ocean-climate system will seem quaint. Even warming to one-fourth of that amount would create a planet that would have nothing to do with the one on which humans evolved or on which civilisation has been built. The last time it was 4C warmer there was no ice at either pole and sea level was 80 metres higher than it is today.

I met University of New Hampshire paleoclimatologist Matthew Huber at a diner near his campus in Durham, New Hampshire. Huber has spent a sizable portion of his research career studying the hothouse of the early mammals and he thinks that in the coming centuries we might be heading back to the Eocene climate of 50 million years ago, when there were Alaskan palm trees and alligators splashed in the Arctic Circle.

“The modern world will be much more of a killing field,” he said. “Habitat fragmentation today will make it much more difficult to migrate. But if we limit it below 10C of warming, at least you don’t have widespread heat death.”

In 2010, Huber and his co-author, Steven Sherwood, published one of the most ominous science papers in recent memory, An Adaptability Limit to Climate Change Due to Heat Stress.

“Lizards will be fine, birds will be fine,” Huber said, noting that life has thrived in hotter climates than even the most catastrophic projections for anthropogenic global warming. This is one reason to suspect that the collapse of civilisation might come long before we reach a proper biological mass extinction. Life has endured conditions that would be unthinkable for a highly networked global society partitioned by political borders. Of course we’re understandably concerned about the fate of civilisation and Huber says that, mass extinction or not, it’s our tenuous reliance on an ageing and inadequate infrastructure, perhaps, most ominously, on power grids, coupled with the limits of human physiology that may well bring down our world. [Continue reading…]

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Bacteria use brainlike bursts of electricity to communicate

Gabriel Popkin writes: Bacteria have an unfortunate — and inaccurate — public image as isolated cells twiddling about on microscope slides. The more that scientists learn about bacteria, however, the more they see that this hermitlike reputation is deeply misleading, like trying to understand human behavior without referring to cities, laws or speech. “People were treating bacteria as … solitary organisms that live by themselves,” said Gürol Süel, a biophysicist at the University of California, San Diego. “In fact, most bacteria in nature appear to reside in very dense communities.”

The preferred form of community for bacteria seems to be the biofilm. On teeth, on pipes, on rocks and in the ocean, microbes glom together by the billions and build sticky organic superstructures around themselves. In these films, bacteria can divide labor: Exterior cells may fend off threats, while interior cells produce food. And like humans, who have succeeded in large part by cooperating with each other, bacteria thrive in communities. Antibiotics that easily dispatch free-swimming cells often prove useless against the same types of cells when they’ve hunkered down in a film.

As in all communities, cohabiting bacteria need ways to exchange messages. Biologists have known for decades that bacteria can use chemical cues to coordinate their behavior. The best-known example, elucidated by Bonnie Bassler of Princeton University and others, is quorum sensing, a process by which bacteria extrude signaling molecules until a high enough concentration triggers cells to form a biofilm or initiate some other collective behavior. [Continue reading…]

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The Anna Karenina hypothesis says that every unbalanced microbiome is unbalanced in its own way

Ed Yong writes: In 2012, Rebecca Vega Thurber looked at the results of the large underwater experiment she had been running for three years—and was disappointed.

Since 2009, her team had been traveling to the coral reefs of the Florida Keys. In some spots, they exposed the corals to nitrogen and phosphorus, to simulate the agricultural runoffs that often pollute these reefs. In other areas, they used wire mesh to keep fish away, mimicking the effects of overfishing. They wanted to know if these sources of stress disrupt the relationship between the corals and the trillions of microbes that live with them—and whether these disruptions lead to the corals’ demise.

Scientists have conducted hundreds of similar studies in humans. They compare healthy and sick people and look for differences in their microbiomes—the vast community of bacteria and other microbes that share our bodies. They aren’t looking for a specific disease-causing bug, like the ones behind classic infections like plague, leprosy, or tuberculosis. Instead, they’re looking for imbalances, where certain species rise to the fore, others slink into obscurity, and the entire community changes for the worse.

That’s what Vega Thurber expected to find in the corals. But that’s not what her postdoc Jesse Zaneveld found when he analyzed the results. The extra nutrients and the missing fish both changed the coral microbiomes—but not in any consistent ways. “It was a pretty dark day after three years of work,” says Vega Thurber. “A lot of students would have thrown up their hands and cried a bit. But Jesse said: You know what, I think I see something strange. It’s a pattern but one we didn’t predict.”

The microbiomes of the stressed corals had become more varied. They didn’t shift in any particular direction—they changed in every direction. And shortly after Zaneveld realized this, he spotted the same pattern—but this time in chimpanzees. Researchers at Yale University had studied the gut microbiomes of chimps that were infected with an HIV-like virus, and found that their microbiomes had also become more variable. [Continue reading…]

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Is the living world more a result of happenstance or repeatable processes?

Zachary D Blount writes: Amazon’s television series The Man in the High Castle, based on the classic novel by Philip K. Dick, presents a nightmarish alternative 1962 in which the triumphant Nazi and Japanese empires occupy a fractured, defeated United States.

This alternate history is spun from the imagined consequences of a minor change in a real event. On February 15, 1933, Giuseppe Zangara opened fire on president-elect Franklin D. Roosevelt in Miami, Florida. Zangara was only 25 feet away, but his attempt failed because he shared the wobbly bench on which he stood with a woman who, as she strained to see, jostled the bench at just the right time to spoil his aim. The show’s version of history did not include the fortuitous jostle. Although the result of such a change might not have been the dystopia the show envisions, history would have been quite different had Roosevelt died that day.

Human history has been wrought from the particulars of unique events and personalities. Indeed, the historical record is rife with instances like the attempt on Roosevelt’s life, where even slight changes could have dramatically altered the course of events. These instances illustrate how the existence of the current world depended on the process of history, linking past to present in a complex web of causality. In other words, human history is contingent. Contingency, philosopher John Beatty has written, essentially means that history matters “when a particular future depends on a particular past that was not bound to happen, but did.” It arises because the future flows causally from the past, but many futures are possible at any given time, and which one comes to pass is determined by the precise, chance-laden way in which a complex tangle of improbable events interacting in improbable ways plays out. Contingency is why we can more or less explain the past, but the future is unpredictable. [Continue reading…]

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Moon had a magnetic field for at least a billion years longer than thought

Science News reports: The moon had a magnetic field for at least 2 billion years, or maybe longer.

Analysis of a relatively young rock collected by Apollo astronauts reveals the moon had a weak magnetic field until 1 billion to 2.5 billion years ago, at least a billion years later than previous data showed. Extending this lifetime offers insights into how small bodies generate magnetic fields, researchers report August 9 in Science Advances. The result may also suggest how life could survive on tiny planets or moons.

“A magnetic field protects the atmosphere of a planet or moon, and the atmosphere protects the surface,” says study coauthor Sonia Tikoo, a planetary scientist at Rutgers University in New Brunswick, N.J. Together, the two protect the potential habitability of the planet or moon, possibly those far beyond our solar system.

The moon does not currently have a global magnetic field. Whether one ever existed was a question debated for decades (SN: 12/17/11, p. 17). On Earth, molten rock sloshes around the outer core of the planet over time, causing electrically conductive fluid moving inside to form a magnetic field. This setup is called a dynamo. At 1 percent of Earth’s mass, the moon would have cooled too quickly to generate a long-lived roiling interior.

Magnetized rocks brought back by Apollo astronauts, however, revealed that the moon must have had some magnetizing force. The rocks suggested that the magnetic field was strong at least 4.25 billion years ago, early on in the moon’s history, but then dwindled and maybe even got cut off about 3.1 billion years ago. [Continue reading…]

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Aliens in our midst

Douglas Fox writes: Leonid Moroz has spent two decades trying to wrap his head around a mind-boggling idea: even as scientists start to look for alien life in other planets, there might already be aliens, with surprisingly different biology and brains, right here on Earth. Those aliens have hidden in plain sight for millennia. They have plenty to teach us about the nature of evolution, and what to expect when we finally discover life on other worlds.

Moroz, a neuroscientist, saw the first hint of his discovery back in the summer of 1995, not long after arriving in the United States from his native Russia. He spent that summer at the Friday Harbor marine laboratory in Washington. The lab sat amid an archipelago of forested islands in Puget Sound – a crossroads of opposing tides and currents that carried hundreds of animal species past the rocky shore: swarms of jellyfish, amphipod crustaceans, undulating sea lilies, nudibranch slugs, flatworms, and the larvae of fish, sea stars and countless other animals. These creatures represented not just the far reaches of Puget Sound, but also the farthest branches of the animal tree of life. Moroz spent hours out on the pier behind the lab, collecting animals so he could study their nerves. He had devoted years to studying nervous systems across the animal kingdom, in hopes of understanding the evolutionary origin of brains and intelligence. But he came to Friday Harbor to find one animal in particular.

He trained his eyes to recognise its bulbous, transparent body in the sunlit water: an iridescent glint and fleeting shards of rainbow light, scattered by the rhythmic beating of thousands of hair-like cilia, propelling it through the water. This type of animal, called a ctenophore (pronounced ‘ten-o-for’ or ‘teen-o-for’), was long considered just another kind of jellyfish. But that summer at Friday Harbor, Moroz made a startling discovery: beneath this animal’s humdrum exterior was a monumental case of mistaken identity. From his very first experiments, he could see that these animals were unrelated to jellyfish. In fact, they were profoundly different from any other animal on Earth.

Moroz reached this conclusion by testing the nerve cells of ctenophores for the neurotransmitters serotonin, dopamine and nitric oxide, chemical messengers considered the universal neural language of all animals. But try as he might, he could not find these molecules. The implications were profound.

The ctenophore was already known for having a relatively advanced nervous system; but these first experiments by Moroz showed that its nerves were constructed from a different set of molecular building blocks – different from any other animal – using ‘a different chemical language’, says Moroz: these animals are ‘aliens of the sea’.

If Moroz is right, then the ctenophore represents an evolutionary experiment of stunning proportions, one that has been running for more than half a billion years. This separate pathway of evolution – a sort of Evolution 2.0 – has invented neurons, muscles and other specialised tissues, independently from the rest of the animal kingdom, using different starting materials. [Continue reading…]

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First support for a physics theory of life

Natalie Wolchover writes: The biophysicist Jeremy England made waves in 2013 with a new theory that cast the origin of life as an inevitable outcome of thermodynamics. His equations suggested that under certain conditions, groups of atoms will naturally restructure themselves so as to burn more and more energy, facilitating the incessant dispersal of energy and the rise of “entropy” or disorder in the universe. England said this restructuring effect, which he calls dissipation-driven adaptation, fosters the growth of complex structures, including living things. The existence of life is no mystery or lucky break, he told Quanta in 2014, but rather follows from general physical principles and “should be as unsurprising as rocks rolling downhill.”

Since then, England, a 35-year-old associate professor at the Massachusetts Institute of Technology, has been testing aspects of his idea in computer simulations. The two most significant of these studies were published this month — the more striking result in the Proceedings of the National Academy of Sciences (PNAS) and the other in Physical Review Letters (PRL). The outcomes of both computer experiments appear to back England’s general thesis about dissipation-driven adaptation, though the implications for real life remain speculative.

“This is obviously a pioneering study,” Michael Lässig, a statistical physicist and quantitative biologist at the University of Cologne in Germany, said of the PNAS paper written by England and an MIT postdoctoral fellow, Jordan Horowitz. It’s “a case study about a given set of rules on a relatively small system, so it’s maybe a bit early to say whether it generalizes,” Lässig said. “But the obvious interest is to ask what this means for life.”

The paper strips away the nitty-gritty details of cells and biology and describes a simpler, simulated system of chemicals in which it is nonetheless possible for exceptional structure to spontaneously arise — the phenomenon that England sees as the driving force behind the origin of life. “That doesn’t mean you’re guaranteed to acquire that structure,” England explained. The dynamics of the system are too complicated and nonlinear to predict what will happen. [Continue reading…]

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Half the atoms inside and around us came from outside the Milky Way

The Guardian reports: Nearly half of the atoms that make up our bodies may have formed beyond the Milky Way and travelled to the solar system on intergalactic winds driven by giant exploding stars, astronomers claim.

The dramatic conclusion emerges from computer simulations that reveal how galaxies grow over aeons by absorbing huge amounts of material that is blasted out of neighbouring galaxies when stars explode at the end of their lives.

Powerful supernova explosions can fling trillions of tonnes of atoms into space with such ferocity that they escape their home galaxy’s gravitational pull and fall towards larger neighbours in enormous clouds that travel at hundreds of kilometres per second.

Astronomers have long known that elements forged in stars can travel from one galaxy to another, but the latest research is the first to reveal that up to half of the material in the Milky Way and similar-sized galaxies can arrive from smaller galactic neighbours.

Much of the hydrogen and helium that falls into galaxies forms new stars, while heavier elements, themselves created in stars and dispersed in the violent detonations, become the raw material for building comets and asteroids, planets and life. [Continue reading…]

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