Photo: J Telling

Gas bubbles from briny water emerging from the floor of a deep mine. The water’s chemical composition could feed microbes, if any are living here, 2.4 kilometers underground.

Water gushing from a deep mine in Ontario has been isolated from the surface for more than a billion years, a Canadian-United Kingdom scientific group reported today. Intriguingly, the water contains hydrogen and methane, which support bacteria and bigger organisms in the ocean depths, another location where sunlight, life’s usual source of energy, is unknown.

Several analyses indicate that the mine water has been underground for 1.5 to 2.5 billion years, more or less.

Tests for bacteria in the Ontario samples are not complete, but scientists have already found microbes trapped for millions of years in a South African gold mine.

The new study could expand the size and age of the immense bacterial realm beneath our feet, and could even help justify the search for life inside Mars, where geologically quiet regions may retain the liquid water that dominated the planet’s surface billions of years ago.

In deducing how long the water has been isolated from the surface, the researchers focused on inert gases like helium, xenon and argon, which abstain from chemical reactions.

The isotopes of an element are chemically identical but have different physical properties, such as mass. Particular isotopes can only come from a limited number of sources, and do not undergo radioactive decay.

The ultimate source of helium-4 is uranium, and measuring helium-4 can produce an age for the fluid, says project leader Chris Ballentine of the University of Manchester. “We know the concentration of uranium in these rocks, and can calculate that it would take X number of years for this level of helium-4 to build up.”

The researchers calculated that the accumulation of helium-4 would require about 1.14 billion years. Argon-40, another stable isotope, derived from potassium, would require 1.5 billion years. Those dates could be off by hundreds of millions of years in either direction.

Three xenon isotopes provided data on isolation from the surface. “Other workers have been looking at how the xenon isotope composition in the atmosphere has evolved,” says Ballentine. “A small amount of the atmosphere is dissolved in water when it is last at the surface, and when the water percolates into the ground, it takes that signature with it.”

The final step is to match the xenon concentration in the underground water to a time when the same concentration was present in the atmosphere; this process yielded an age of about 1.5 billion years.

Answering the “so-what?” question

The study gives a new view of how water behaves deep underground, says Ballentine, who studies fluid migration. Knowing how fluids form and move will, for example, shed light on what may happen if carbon dioxide gas is pumped underground to reduce greenhouse gas pollution.

Although the ancient water contains methane and hydrogen, which support bacteria in some locations, the “million dollar question” remains to be answered, Ballentine says. Nobody yet knows whether life is present in the water from the Ontario mine. Still, he adds, “We have found an environment that can host life, support it and nurture it for hundreds of millions, or billions of years.”

Because the ancient rock in the Ontario mine is located on the Canadian Shield, where earthquakes and volcanism are absent, “the most important implication is the extent of time that these environments can support life… without being disrupted.”

It’s almost certain that similar locations exist elsewhere, Ballentine adds. “Eventually we hope to find a spectrum of ages that would allow us to … start building a far better understanding of how life finds these pockets, evolves in them, and survives in them.”

Admittedly, that statement is premised on a big “if.” As Ballentine concedes, “We don’t know if there is there life down there, or even what it would look like.”

We may call this the age of information, but we could also call it the age of steel. More than 1.5 billion tons of steel are made each year for bridges, concrete reinforcement, vehicles and building frameworks, among many other purposes.

Photo: Wikimedia Commons

The Hulme Arch Bridge, at Hulme, Manchester, England, is a harmonious construction of steel cables and arches.

Steel is usually about 99 percent iron, and the tight bond between iron and oxygen in iron ore explains much of the environmental cost of making steel.

Now MIT professor Donald Sadoway has found a way to sidestep many of these drawbacks with a 1565° C process that uses electricity to separate iron and oxygen.

A backward battery

Electrolysis is the reverse of a battery. Both batteries and electrolytic cells contain an electrolyte that conducts electricity between two electrodes. In both cases, the process alters the chemistry of the electrolyte, and an electrical current flows.

In a battery, chemical energy in the electrolyte is converted to electrical energy. In electrolysis, electrical energy is converted into chemical energy.

In iron electrolysis, reduction — the chemical reaction that allows iron to release oxygen — occurs at an electrode called the anode. Nearly pure iron pools at the other electrode.

In conventional iron smelting, the oxygen reacts with carbon in coke, a carbon fuel, to make carbon dioxide. The molten iron is brittle, due to a high carbon content, so a second step is needed to drive off that carbon.

Both processes make carbon dioxide pollution.

Coke, a fuel used to strip oxygen from iron ore, was made in this English coke oven. Rollover to see air being blown through molten iron to clear carbon leftover from the coke. This Bessemer process is no longer used, but impurities remain a hindrance in steelmaking.

Credit 1: Earthwatcher, (rollover) 2: Republic Steel, Youngstown, Ohio, Wikimedia Commons

Because the energy to cut the bond between iron and oxygen — and much of the electricity used to refine steel — both originate in coal, the iron and steel sector is “the second-largest industrial user of energy … and the largest industrial source of CO₂ emissions,” according to the International Energy Agency.

By improving efficiency, the new process should cut down on greenhouse gases. However, although because electricity is still needed, the size of the benefit depends on how the current is generated.

Still, the process can, judo-style, convert the oxygen in iron ore from a liability into an asset. “Oxygen bubbles float to the top, and you can collect them,” says Sadoway. “You are making, for every ton of iron, two-thirds of a ton of oxygen that’s industrial quality, marketable.”

Amazing anode

The critical advance is an anode made of chromium and iron that can survive a 2850°F, oxygen-rich process — conditions conducive to a chemical reaction that would obliterate most materials.

Instead, a thin film of metal oxide forms on the anode in the intense heat. “It’s remarkable,” says Sadoway. The oxide, he says, “forms a protective layer that prevents further consumption of the base metal — yet at the same time, is not resistive to any great extent.”

That allows an electric current to enter the hot brew of iron oxide.

Hurdles remain. “I am not saying anybody will take a wrecking ball to an integrated steel plant,” Sadoway says. But he thinks an electrolytic smelter could avoid the need for a sinter plant to process iron ore, a coke oven to produce coke, and an oxygen furnace to remove excess carbon left over from the coke.

Photo: Shutterstock

Huge tonnages of steel reinforcing rods are used to strengthen concrete.

Steel plants cost billions of dollars, and must produce a couple of million tons per year to make money, Sadoway says. If the electrolytic process, with its reduced need for fossil fuel and equipment, survives further testing, smaller plant expansions could be possible, he says.

Any climate-based restrictions on carbon dioxide pollution will only help the new process become a player in the giant steel industry, Sadoway says. “We are hoping there will be early adopters,” he says, “if the price point is lower and there is an environmental imperative toward clean steelmaking.”

A field of volcanoes you have never heard of will wake up, and if it fulfills its geologic potential, the consequences will be heard around the world.

Curiously, Laguna del Maule, situated along the spine of the Andes, doesn’t even look like a volcano. No towering peak, no plume of smoke or steam, no stench of sulfur. But 36 times in the past 20,000 years, volcanic vents surrounding the lake basin have created monster fields of lava — with huge deposits of volcanic glass, pumice and ash.

Once, almost a million years ago, this volcano field had an eruption that, if repeated, could change history by affecting air travel, agriculture and climate. Tantalizing scraps of lava indicate enormous eruptions 1.5 million and 336,000 years ago.

It’s a maxim of geology: What happened before can happen again.

The volcanic field is 20 kilometers in diameter, and the recent surge in attention is largely due to a widespread, 1.5 meter rise since 2007. “That’s phenomenal,” says Brad Singer, a professor of geoscience at the University of Wisconsin-Madison, who began studying this part of the Andes 20 years ago. “There is no other volcano in the world that is going up at this rate.”

Other causes for concern include swarms of earthquakes, horizontal spreading, spreading faults, and new detections of carbon dioxide gas that likely signal the enlargement of the underground magma pool that powers the volcano.

Eruptions can be ranked by estimating the volume of volcanic ash (mainly tiny shards of glass) they release. In 1980, Mt. St. Helens released about one cubic kilometer. In 1991, Pinatubo in the Philippines sent more than 10 cubic kilometers; its ash and sulfur gas injected into the upper atmosphere cooled the planet for two years.

About 950,000 years ago, an eruption at Laguna del Maule spewed dozens of cubic kilometers — perhaps more than 100. The eruption blanketed Argentina, downwind, with ash.

Based on data from Geological Society of London, 2005 and Gunder and Mahood, 1988. Graphs by The Why Files

The bigger the eruption, the less common it is. Laguna del Maule could go back to sleep, or (rollover) enter the history books as the largest eruption in recorded history.

Past is prologue

A 100 cubic-kilometer eruption could cause global cooling, and intense damage to agriculture could affect the entire globe.

Because the only people around Laguna del Maule are the horsemen who drive cattle in the summer, the immediate human impacts will be limited — unless giant flows of hot rock or debris reach Chilean cities. But dense ash-fall during the growing season could devastate agriculture in Argentina, to the east.

Just 50 kilometers north of Laguna del Maule, a similar volcanic field, called Calabozos, has had three super-eruptions in the past million years, spewing about 1,000 cubic kilometers of ash in total.

Those eruptions rank among the largest in a million years.

The Why Files

Laguna del Maule, a massive volcanic complex in Chile, could change the planet, with an eruption like three giants at nearby Calabozos. Maule could be returning to life. How dangerous is that?

The immediate cause of concern at Laguna del Maule comes from radar satellites and the global positioning system, which show that 1.5-meter rise in six years. The accelerating uplift is almost certainly due to new magma entering a pool located five kilometers underground.

In 2013, with support from the National Science Foundation, UW-Madison geoscientists began a field campaign to gather more basic data on Laguna del Maule.

“Our aim is to try to figure out if magma is actively intruding in the crust below the volcanic field,” says Singer, who worked at the site with U.S. Geological Survey expert Wes Hildreth, who started the first systematic mapping of the area in the 1980s. “We hypothesize that this is what is inflating the crust,” Singer says. “It’s like a balloon blowing up the surface.”

History, says Singer, is usually a good guide to the future. Laguna del Maule has “had at least three million years of pretty constant igneous [molten-rock] activity, and about every half million years it looks like a fairly substantial, caldera-forming eruption. Are we overdue for another?”

A caldera is a ring-shaped structure formed when by collapse when a giant pool of magma is vented to the surface.

The questions we ask

“Volcano” and “prediction” are not words that geologists like to join together, but the essential goal at Laguna del Maule is to understand the situation well enough to answer a simple question: How likely is an eruption that would be large enough to affect the region or the planet?

How much do we need to worry?

Singer hopes that the 2013 exploration of Laguna del Maule will soon be augmented with a wider variety of analytic techniques:

These techniques gain precision if their data are merged, Singer says. Many methods “can give a fuzzy picture of what’s down there, but the more techniques you can bring to bear, the more you can tighten up the boundaries between different materials” and so get a better picture of the magma and its potential routes to the surface.

Need a date?

If you need a date, Singer is a good guy to know, at least if you want to date rocks. A specialist in geochronology, Singer uses sensitive instruments to squeeze out a date of formation for igneous rock, meaning when the rock solidified from cooling magma.

The overall goal at Maule is to tease out the timing of the many lava flows in the basin.

One dating technique relies on the radioactive decay of potassium into the gas argon, which follows a schedule set by the half-life of the isotope potassium-40.

Magma is hot, and any argon present will diffuse into the crust, but argon is trapped after magma cools into lava at earth’s surface. “Once it cools past a certain point, then argon stops diffusing, allowing argon produced from radioactive decay to build up,” says Nathan Andersen, a Ph.D. student in geoscience at Wisconsin who is dating recent lava flows at Maule.

Potassium-40 decays into argon-40, and so counting each isotope becomes the foundation for calculating the date of cooling.

However, potassium decays slowly, and this system has yet to date recent flows at Laguna del Maule, which are apparently younger than 2,000 years.

The eyeball on the highball

High-tech is eye-catching, but once you know what you are looking for, eyesight offers insight. Look at the large granite intrusions underneath Tatara San Pedro, a nearby volcano. The granite is apparently the remains of a magma chamber which cooled about 6 million years ago.

“It looks like a frozen magma body that is analogous to the magma body we think is active beneath Laguna del Maule today,” Singer says. Similar bodies of frozen magma have risen over 80 million years in California’s Sierra Nevadas. “But here, it’s now 2,500 meters above sea level. That’s 7,500 meters of uplift in 6 million years!”

The express elevator that is raising Laguna del Maule can be seen with the naked eye. White streaks on certain parts of the shoreline contain diatoms and ash that were deposited in the lake. “These are a sign that the uplift has been going on for many centuries,” Singer says.

The lake bench, 200 meters above the existing lake, shows an old shoreline that, when formed, was as horizontal as the lake itself. Singer suspects that the profile of the bench carries a long-term record of uplift.

Faults, which show how adjacent sections of rock have moved against each other, are another eye-catcher. Last year, the Wisconsin scientists found new evidence of horizontal spreading and faults; these structures show earth movement, and could facilitate the rise of magma and an eruption.

Thou shalt know thy rocks

If you know what you are looking at, small outcrops can play a large role in understanding the geologic history at Laguna del Maule. Analysis of the chemistry, minerals and texture of rocks can show that remote outcrops are remnants from a single eruption, or a single magma body. “When you start to see rhyolite on one side of the lake,” Singer adds, “and identical rhyolite on the other side, and you try to imagine how big the system must have been to produce both of those eruptions, that really grabs your attention.”

(Rhyolite, an uncommon type of magma that is rich in water and silica, and resistant to flow, is the most explosive and dangerous magma on the planet.)

Finding chemically similar lava over such a large area indicates that a large eruption is possible in the future.

Measuring the ground shaking

When the earth moves, the resulting vibrations convey clues about the planet’s internal structure. Both earthquakes and deliberate explosions can produce a “CAT scan of the crust,” based on how waves are transmitted, reflected, absorbed or converted into different waves, says Clifford Thurber, a seismologist at UW-Madison.

In the first months of this year, seismographs at Laguna del Maule were “detecting repeated swarms of earthquakes, clusters that happen close together in time and space,” Thurber says. “Those are hallmarks of magmatically active volcanic systems, but they do not prove anything. On the other hand, if it were seismically silent, one would have to wonder if anything is going on.”

After a swarm of earthquakes in March, 2013, scientists at the Chile’s Southern Andes volcano observatory issued a yellow alert, indicating that an eruption was possible in weeks or months.

Stronger and longer earthquake swarms and tremors are danger signs, Thurber says. “If we get sustained tremor, a low-level shaking that continues for hours to days, then we would get nervous. If we start to get very large earthquakes, 6 magnitude, it’s time to go.”

Thurber is introducing state-of-the-art computer analysis of seismic waves that will pinpoint arrival times more precisely. With improved earthquake locations, “We can do a better job of clarifying the structures that produce the earthquake,” Thurber says.

With a seismic expert on the line, we had to ask why the giant 2010 Maule earthquake did not trigger an eruption at nearby Laguna del Maule, just a few hundred kilometers the east of the epicenter. “It’s odd,” says Thurber. “This happens around the world. Sometimes a large earthquake triggers activity, and sometimes it does not. The volcano has to be ready.”

Gas attack!

Volcanoes can release staggering amounts of gas: Mt. Pinatubo coughed up an estimated 20 million tons of sulfur dioxide.

Carbon dioxide, a hallmark of basalt, is the big concern at Laguna del Maule, and
despite difficulties with two brand-new carbon dioxide meters, Glyn Williams-Jones, a volcanologist at Simon Fraser University in British Columbia, did find some elevated levels along the lakeshore in 2013.

“That means there is basalt entering the magma chamber from below,” says Williams-Jones.

Newly arrived, extremely hot basalt could interact with the existing rhyolite magma and boost the odds of eruption.

The Why Files

Helene Le Mevel, a graduate student, adjusts a meter that measures the local gravity field with astonishing precision. If significant amounts of magma are rising underground, gravity should be weaker in next year’s measurements — if the measurements are precise and accounts for the ongoing uplift of the area.

Electrical currents

To get a better sense of what’s happening under ground, geophysicists can measure electrical currents and magnetic fields inside Earth. “The surface is bathed by electromagnetic radiation from the sun, and there is an electrical response at depth,” says Singer.

The technique, called magnetotellurics, is used in geothermal energy exploration, and an energy company has already used it to find a shallow steam field just west of the caldera that could power a geothermal electric generator.

Magnetotellurics has already revealed that the crust around Laguna del Maule is about 40 kilometers thick, and that the magma body is about 5 kilometers below ground, Singer says. In the future, the technique could help define the size and location of melted crust near the magma chamber.

Gravely measuring gravity

Accurate measurements of gravity are another telltale about changes in the hot, molten magma. Because matter expands as it warms, magma is 10 percent less dense than surrounding rock, explains Basil Tikoff, a UW-Madison specialist in large-scale structure of the Earth, such as faults, old mountain belts and tectonic plates.

Gravity “does not have the resolution of other techniques, and it requires an enormous amount of fieldwork,” Tikoff says. “It’s a kind of geophysics that very few geophysicists do now.”

In March, Tikoff, graduate student Helene Le Mevel, and Williams-Jones installed 38 gravity stations on two lines crossing the center of uplift. The gravimeters are built around an ultra-precise spring that allows a suspended weight to respond to gravity. Although the meters are more than one-h century old, they are accurate to one part in 100 million. “If there is an earthquake, we have to turn the gravimeter off and wait,” says Tikoff. “If the land is going up and down, the gravimeter can see that, even if we can’t feel it.”

The pull of gravity decreases as  the instrument gets farther from the center of the Earth. “This instrument is so sensitive that if we went up a few stairs, you could tell,” Tikoff says. Therefore, Laguna del Maule’s pervasive uplift must be mathematically removed from subsequent measurements.

Baseline measurements taken in March and April will serve as reference points for subsequent surveys early in 2014. Located at the crest of the Andes, Laguna del Maule will be impassable until then due to its astonishing snowfall.

What comes next?

Laguna del Maule is a contradiction. To people who would be affected by a large eruption (which could include all of humanity in a super-eruption) it’s a threat.

But to geologists, it’s an opportunity to see how Earth is changing, and that is what draws Singer back. “The processes of deep Earth history are abstract,” Singer says. “I am more attracted to things that happen to the planet on a rapid time scale, such as glaciers and volcanoes. These take place on a human time scale.”

March, 2013, The Why Files

Gravimeters must be protected from vibration due to wind. Graduate student Tor Stetson-Lee blocks wind as Basil Tikoff measures gravity on the east shore of Laguna del Maule. That flying-saucer-on-a-stick is a GPS receiver able to measure altitude in millimeters.

The explanation for the new activity is pretty clear, Singer says. “There is no reason other than new magma to explain uplift of that size.”

The rapid uplift, combined with swarms of small earthquakes, apparent releases of carbon dioxide, and spreading of faults cannot go on forever. If they continue, the magma’s upward pressure will eventually exceed Earth’s ability to contain it.

Then Laguna del Maule erupts.

Until then, geoscientists see a chance to observe in real-time processes whose results can be seen all over the planet, and there is lots to be learned before the eruption, says Singer, who normally looks, forensic-style, after the eruption. “I try to reconstruct the history of magmas that feed the volcano, and how the processes inside the magma affect the way the volcano erupts, whether it’s explosive or passive. I try to stay away from them when they are erupting.”

Volcanoes usually emit a sequence of warnings, including a critical change in seismic signals, but nobody knows if Laguna del Maule will break the mold or follow it, adds Thurber, the seismologist. “We don’t have perspective. Studies that have been done on systems like this have exclusively been done after they have blown their top.”

Volcanoes are inherently unpredictable, especially the bizarre giants like Laguna del Maule, Thurber says. “We have no idea what the timeframe is to go from the rapid inflation we see now to an eruption. It could stop inflating and say ‘I’m done for now.’ It’s completely unpredictable; it could erupt tomorrow, next week, next year, next decade, next century. We don’t know for sure it is going to blow, but it sure as heck looks like it. If it erupts, the fact that a study had been done beforehand would be phenomenal, and unique in the world.”

A field experiment in South Africa finds that vervet monkeys change their taste in food when they join a new group, providing further evidence for “social learning” in animals. When the experiment started, monkeys were fed blue or pink corn. One color had the usual taste, but the other was politely described as “highly distasteful.”

That quickly taught the monkeys a lesson on palatability.

The researchers came back four months later to observe what newborns were eating. No shocker: they followed mom’s advice regarding corn color, even though both colors now tasted the same.

Then came the interesting part. As vervet guys mature, they migrate and join new groups. Intriguingly, 10 of the 15 migrant males immediately changed their preference to match the culture of the new group; four others had to wait to switch until the dominant males had eaten their fill.

“We designed the study for infants, which is why we had the four-month gap, so the babies would be ready for solid foods,” says first author Erica van de Waal, a post-doctoral researcher at St. Andrews University in Scotland. “But when we followed the male migrations, Wow! This monkey was trained to eat pink corn, and… to see him join the new group who all eat blue, and he decides, ‘No, I have to eat blue.’”

(Tactical note: The researchers tested both combinations. For half the groups, pink started out as yucky, for the other half, blue started out tough on the tongue.)

Mother knows best

Following the local lead has obvious evolutionary benefits, says van de Waal. “In a foraging diet, it’s really important” to benefit from the local knowledge.

Because females stay home on the range, they have enough local knowledge to survive. Not so for the moving man, van de Waal says. “He may see a new species of tree, or the toxic composition of edible fruits will change. They need the best local information to survive in the new environment.”

That’s especially true because males make multiple migrations, and thus seldom become experts in the local restaurant scene. “You could think that a dominant male that was in a group for 10 years would have as much knowledge as the females, but these males change groups a lot,” van de Waal says.

Although both colors had the same taste in the new location, even after migrant males tasted their previous preference, van de Waal says, “They still thought, ‘If the locals want that one, it must be better.’

“We know that vervet monkeys are opportunistic and adaptable, they have spread across Africa, so as soon as they found that both foods taste the same, we thought the ratio would drop to 50-50,” van de Waal says. “Not at all. Even the ones with previous knowledge adopted the new normal color.”

Shocker: This guy didn’t want advice

What about that 15th male, who remained his allegiance to the corn color of his youth? “It’s kind of strange,” says van de Waal. “He entered a group where the dominant male had disappeared, he was a big, strong adult male, a full adult, and he directly became the dominant male, and did not seem to care about what the others were eating.”

And that suggests that the survival advantages of changing food preferences to suit the “culture” in a new location may not fully explain the results, van de Waal says. “Maybe it confirms there is something social going on.”

At any rate, you can’t fool the true experts, she says. “The females did not try the color he was eating. The dominant females are always conservative; he did not influence the dynamic of the group.”

On the other hand, “This is sample of one,” says van de Waal. “Maybe he is just a stupid male that does not care what the others are doing.”

It’s been 15 years since a University of Wisconsin-Madison researcher isolated embryonic stem cells — the do-anything cells that appear in early development. It’s been six years since adult human cells were transformed into the related induced pluripotent stem cells.

And yet the early hope to grow “spare parts” — turning stem cells into specialized cells for repairing a failing brain, pancreas or heart, remains mostly promise rather than reality.

Researchers have since found how to transform stem cells into a wide variety of body cells, including heart muscle cells, or cardiomyocytes. But the holy Grail — tissue supplementation or replacement — remains tantalizingly out of reach.

Last week, Why Files attended a symposium on treating cardiovascular disease with stem cells, at the BioPharmaceutical Technology Center Institute near Madison, Wis. We found the picture unexpectedly complicated: as multiple kinds of stem cells are grown and delivered in a bewildering variety of ways to treat a catalog of conditions.

So far, stem cells have not been approved to treat any heart disease in the United States.

Still, the need remains clear. Disorders of the heart and blood vessels, which deliver oxygen and nutrients to the body, continue to kill. “Today, one of every 2.6 Americans will die of some cause related to their heart,” writes Columbia University Medical Center.

Not an easy project

Heart muscle dies when a blood clot blocks the blood supply. Heart muscle does not regenerate, and a major attack can cause death or a lifetime of heart disease.

So why have injections of heart muscle cells grown from stem cells produced only transitory benefits? “There is a battle between the heart and what it is willing to receive,” says Warren Sherman, director of cardiac cell therapy at Columbia University Medical Center.

“Even with normal heart architecture, it’s not a very friendly place for cells to find a home,” Sherman says. “The fluid flow rate is so high that many things get pushed out.” And in the areas that are scarred by heart attack, “there is nothing for the cells to adhere to.”

As a result, “Cell retention rates are just horrible,” Sherman says. “You are lucky, with any [heart] disease, with any delivery method, if you have 5 percent of the cells present 24 hours later.”

The brain or pancreas, two other potential sites of cell therapy, do not suffer from these hindrances.

Researchers have injected muscle cells into blood vessels, inside or outside the heart. They have also injected cells into the muscle of a heart that is still beating. A batch of stem cells can also be seeded onto a “patch,” a fibrous glob that gloms onto the damaged muscle.

Got the money?

The large, phase III clinical trials needed for FDA approval of a biological treatment typically enroll hundreds of patients at multiple sites, which can be hideously expensive. “Any phase III trial is going to cost at least $100 million, and it goes up from there,” says Hunt.

Even when preliminary results are promising, trials can be torpedoed when the sponsoring company changes its business goals, is bought out, or runs short of money.

For example, the “MARVEL” study, which grew stem cells from the patient’s muscle into early-stage heart muscle cells, or myoblasts, produced “a strong indication of improvement in symptoms and exercise capacity in 21 patients,” says Sherman, who played a role in the trial. “It was safe, but the company [Bioheart, Inc.] was broke … and that’s how it ended. Whether the results were positive or negative, we would have put up a number, and that number still does not exist.”

Stem cell trials must also account for procedures in particular medical fields, said Ann Remmers of Aastrom Biosciences. After a recent stem-cell trial for chronic limb ischemia, which reduces blood flow and can require amputation, “we needed to think through the practice patterns of vascular surgeons. We wanted to treat subjects who had no further options for surgery, but the surgeons we work with are very talented,” and were able to do reparative surgery until shortly before amputation was needed. “The vascular surgeons are making the decisions based on what is best for the patient, and we needed to have thought more about how to integrate the trial into their practice,” Remmers said.

Special stem cell delivery

To date, stem cells have not done much to help people with heart disease. Despite some limited improvement, by six months, the benefits have generally washed out.

“Typically you just give a single dose,” says Eric Schmuck, who works with Amish Raval, an assistant professor of cardiovascular medicine at UW-Madison. “Nobody has done two doses.”

And so Raval and Schmuck are testing a two-dose “prime and boost” strategy. The mesenchymal stem cells they are using originate in the placenta, and are known to fight inflammation, slow down the immune system, and promote blood-vessel growth.

In an ongoing test with pigs, the prime dose is given intravenously shortly after blood flow to part of the heart is stopped, Schmuck says. The resulting inflammation seems to attract the stem cells, which calm the inflammation.

Thirteen days later, 13 injections of the booster dose — totaling about 100 million cells — are squirted into the edge of the damage. “The first dose alters conditions to make the heart more receptive to the second dose,” Schmuck says. “When you reduce inflammation and stimulate blood-vessel growth, the cells have an easier time grafting.”

The experiment is ongoing, but there are early measurements in blood pressure and volume, and heart size and weight, Schmuck says. The treated hearts show a more regular heartbeat, without a systemic immune response.

Curiously, Schmuck doubts that the benefits come from cell replacement. “I think the cells secrete good vibes, juices, that either attract innate stem cells from the heart or help preserve heart muscle cells that are damaged.”

If the study continues to be safe and beneficial, the researchers hope to propose a small human trial of prime and boost within a couple of years.

Meeting your matrix

In the body, most cells grow in a mushy, 3-D world, but in the lab, they grow on hard, flat dishes. This discrepancy may account for some of the difference between real life and lab-life results, says Brenda Ogle, an associate professor of biomedical engineering at the University of Wisconsin-Madison.

Ogle is exploring structures to hold stem cells in a more lifelike configuration, and she finds that mesenchymal stem cells differentiate much as they do on a 2D dish, when held in a lab-built 3D structure of polyethylene glycol.

However, the timing of differentiation is different, Ogle says, possibly due to altered activation of cell-surface receptors, or to the fact that “tissue culture takes place on a stiff, rigid surface,” while the 3D structure is more flexible.

The 3D structure that Ogle is testing contains bits of extra-cellular matrix (ECM) proteins, such as collagen, which normally separates cells. “People used to think of ECM as girders and beams, a structural support for cells,” says Ogle. “We now know that it has other important functions,” such as storing growth factors. “If there is tissue trauma and the ECM breaks down, that may release growth factors that help the tissue respond to damage.”

Ogle’s goal is to build a patch that could stick to the heart and deliver stem cells. Although a disturbing number of cells are flushed away with existing delivery technologies, Ogle’s lab has achieved 70 percent retention by delivering mesenchymal stem cells on a patch made of cow collagen.

Endothelial cells to the rescue?

On the inside, of blood vessels are lined with endothelial cells that help regulate blood pressure, prevent clots, and regulate transport of molecules in and out of blood. Endothelial problems are a cause and symptom of a variety of conditions, including stroke, diabetes and coronary artery disease.

Could endothelial cells play a role in organ regeneration? Yes, says Shahin Rafii, a Howard Hughes Medical Institute investigator at Weill Cornell Medical College. “People think of endothelial cells as inert conduits to deliver oxygen and nutrients. We think maybe they can be the magic bullet, that we can transplant them to promote organ regeneration.”

Like the prime and boost example, the effect is less likely to be cell replacement and more creating a hospitable niche for existing heart cells.

The cells that line capillaries are in a unique position to affect stem cells, Rafii says. “Every stem cell, everywhere, resides next to a capillary. If I tweet a molecule through the capillaries, within seconds, every stem cell in body will know what is going on.”

Rafii adds that endothelial cells trigger growth in organs that are able to regenerate, like the liver and bone marrow. But the regrowth fails if, for example, the endothelial cells come from a different tissue.
Focusing on regeneration is an alternative path to stem-cell therapy, Rafii says. “I argue that if we can engineer organ-specific endothelial cells and transplant them, they will find the right zip code [in the target organ], and cause regeneration.”

If the endothelial cell hypothesis is unusual, so is the proposed source: cells gathered from amniotic fluid during amniocentesis, a common test for fetal health and gender.

“I believe amniotic cells can be used to regenerate bone marrow, lung and liver, if we can solve the immunology problem,” Rafii says. Discarded tissue from the 1 million amniocentesis procedures performed each year in the United States could provide an enormous, diverse stockpile of cells for transformation and transplant.

If Rafii is correct, understanding the signals from endothelial cells could be a significant advance, Kamp says. “Maybe the endothelial cells are telling the heart stem cells and other repair mechanisms to turn on. If you have sick endothelial cells, like with coronary artery disease, those endothelial cells are probably not singing the right song. If we could help them, we could help the heart.”

Making sense

Nobody can say where, how and when stem cells will become an accepted treatment for cardiovascular disease. But if you combine the extraordinary promise of these cells with the scientific creativity and the profit potential of any treatment that really restores heart muscle, it’s almost inevitable that hearts and blood vessels will eventually benefit from stem cell therapy.

Kamp thinks considerable progress has taken place: “Cell therapies are advancing. We are testing different cell products in patients with heart disease. The real question is what is going to be the right cell for the right job. There are different diseases with different needs, and different cell products and delivery mechanisms. All that has to be worked out, optimized and tested. Clinical trials to develop these take time.”

Modified from original by American Heart Association

Rates of mortality are diminishing from stroke and coronary heart disease

But patients are still dying, and stem cells are only available from a few small clinical trials within the world regulated by the U.S. Food and Drug Administration. For patients, that’s frustrating, says Sherman, who has been involved with cardiac cell therapy for many years; “I feel greatly for patients out there. We have raised the level of expectation, from the moment stem cells hit the front page, and fairly so, for good reason. Yet it has dragged on, again for good reason, and we still don’t know how to advise them.”

Basic breakthroughs always seem to take too long, Kamp observes. Research into implantable defibrillators, used to stop heart attacks by stabilizing heart electrical rhythms, began in the 1960s, but they were not in wide use by surgeons until the ’90s. “It’s not unusual for these revolutionary technologies to take a decade or more before they start to enter clinical practice.”

It’s the middle of February, and the world is learning that Oscar Pistorius, a sprinter who ran in the Olympics, has been charged with murdering his girlfriend. In the summer of 2012, Pistorius, the first double amputee Olympic athlete, a hero for his personal grit.

His ultra-efficient carbon feet, inevitably, led to the nickname “blade runner.”

The carbon blades that enabled Oscar Pistorius to race in the 2012 Olympics are strong, springy and fast. Rollover to see the structure of your foot. “This prosthetic looks almost nothing like a human foot,” says Jeremy DeSilva of Boston University. “It has a single rigid element, strong enough to push off the ground, elastic enough to put a kick into the step.”

Photos: Will Clayton (Pistorius), Ryan Lines (x-ray)

At the annual meeting of the American Association for the Advancement of Science, the news about blade runner served as an ideal but sad lead-in for Jeremy DeSilva, an anthropologist at Boston University who studies body structure. Comparing photos of the blades to an X-ray of the foot, DeSilva observed drily that “The [human] foot is not what you would design from scratch.”

Instead of this single bladelike structure, he said, “our foot has 26 bones. Our ape relatives have 26, and that’s the story in the primate line. Many problems we have today are the result of that.”

Our tree-climbing primate ancestors needed a foot able, like their hands, to grab and hold. Now that we are walking on our feet, those moving parts lead to sprained ankles, heel spurs, collapsed arches, Achilles tendinitis, osteoarthritis and plantar fasciitis, says DeSilva. “It all goes back to upright walking.”

Evolution ≠ perfection

Evolution is the organizing principle of biology: a fact of life. Plants and animals that look alike usually share common ancestors. Organisms that have similar genes got them from the same ancestor. And ditto for creatures with similar proteins.

Evolution is driven by selection: The genes of organisms that can survive and produce offspring are represented in the next generation. Genes that fail these twin tests disappear.

But just because evolution has crafted millions of working answers to survival and reproduction does not make the results ideal. “It’s been known for a long time, since Darwin, that evolution does not produce perfection,” says DeSilva. “Evolution works from raw material that was previously created, and it modifies and tinkers with it, producing the biological equivalent of duct tape and paperclips. If the organism survives, passes along its genes, then off we go.”

The genes and structures — like the spine, digestive tract or brain — most conducive to survival and reproduction are repeated, often with modification due to chance mutation.

Instead of inventing from whole cloth, evolution works through a “good-enough” process called descent with modification.

And that brings us to the “scars of evolution,” a theory proposed in 1951 by Wilton Krogman that proposes to explain a number of human shortcomings. DeSilva was one of several scientists at the February meeting who blamed our woes on the ones who came before — the predecessor primates and other mammals whose genes still largely control our fate.

Got the walking blues

Human foot problems are sometimes blamed on shoes, sidewalks, or the life of a couch potato, but DeSilva says nay. “It’s amazing how the fossil record indicates that foot problems go back into the past.”

Some feet have much better design. The ostrich for example, is a biological version of the sprinter’s carbon blades. “Ostriches have a fused bone at the ankle,” DeSilva says, “and big tendons that give it that elastic energy, that kick.”

Blame the ancestors. Birds, DeSilva says, “had a 230-million year head start on us, because they evolved from bipedal dinosaurs,” while people have only been walking on two feet for 4 or 5 million years. “Our ancestors were quadrapedal, spending a good deal of time in the trees, and they evolved this very mobile, grasping foot, made for living in the trees.”

When great-grandma started walking upright, evolution began to remodel her foot, stabilizing it with oodles of ligaments, “But these were Band-Aids,” DeSilva says. “Natural selection did wonders to modify the ape foot so we could walk on two legs, but that led to problems.”

The in-and-out rotation of the ankle helped our ancestors grab limbs, but it also facilitates sprains. And if you stand on one leg, DeSilva says, “You wobble; the ankle is very unstable, and you do this every single time you take a step.”

Through the process of convergent evolution (similar structures arising from different predecessors) foot bones have fused in some mammals that have been walking for millions of years. “In the horse and the antelope, the ankle is reduced in size, the metatarsal bones have fused, and the pedal digits have reduced to one,” says DeSilva. “That’s biomechanically better.”

No sense searching for a collapsed arch in an ostrich or a horse (both sprinters that could outrun blade runner). “You can’t get a collapsed arch if you don’t have an arch,” DeSilva says.

Understanding the evolution of the structure that helps us stand, walk and run shows that evolution is not just “a dusty old science, behind glass in a museum,” says DeSilva. “Our evolutionary history explains why we are the way we are today. Evolution impacts us today.”

This skeleton shows the three major curves of our spine (from top): cervical, thoracic and lumbar.

Modified from original engraving “Die Gesammten Naturwissenschaften für das Verständnis weiterer Kreise,” published in Essen, Germany, Georg Holderied

Backed into a corner

Worldwide, back problems are humanity’s number-six ailment, says Bruce Latimer, professor of anthropology at Case Western Reserve University. Among musculoskeletal issues, backs rank first. “If you want a place that is really a problem, it’s the back,” he says cheerfully.

Back trouble is rooted in our descent from animals who walked on all fours, with the back in a horizontal position. The transition to the vertical entailed an extra curve to balance the weight over the hips, and while these curves alleviate the shock of walking, they are “a recipe for trouble,” Latimer says.

The spine is built of vertebrae and disks, and “If I gave you 24 cups and saucers, each representing a vertebra or a disk, if you were really careful, you could stack them,” Latimer says. “Now I want you to add in those curves, and if I gave you all the duct tape in the world, you could not possibly do it.”

The pronounced lumbar curve is found in no other mammal, Latimer says. Add in that reverse curve in the thorax, and a third in the neck, “and you wonder why there is a problem?”

On the plus side, our spine is highly flexible, and we are the only mammal that can do a back bend. Twisting and bending have other benefits, Latimer says. “Apes get disk infections because they don’t have a flexible spine, so they have trouble pumping nutrients into their disks.”

Disking disaster

Those disks, however, can get crunched by gravity and stresses due to our upright gait, Latimer says. “As we walk, we throw our upper body 180° out of synch with the lower body, as the right arm goes forward, so does the opposite leg. We are constantly twisting, torqueing the spine, and ultimately after millions of repetitions, we wear through the fibrous exterior of the disk.”

Twisting and compression can translate into a disk that is “slipped” or “herniated,” as the soft center bulges and compresses the nerves, creating excruciating back and leg pain known to millions. “If you live long enough, you will have a herniated disk,” says Latimer.

Evolution tried to compensate with larger vertebrae, which reduce bulging and popping in the disks, but these big vertebra are built of porous — and therefore weaker — bone. “When we have the endocrine shift at menopause, women lose bone, and get osteoporosis,” says Latimer.

The great apes do not lose bone mass as they age, but neither do they get the spine-bending disability scoliosis.

After Charles Darwin first published his theory of evolution in 1859, scientists looked to it for explanations of the structures visible in plants and animals. Now, they realize that evolution has present-day significance. “Evolution tinkers with what it has, can’t create perfection; it can’t invent a brand new spine,” says Latimer. “If you think [the spine] is an intelligently designed structure, I suggest you get a new engineer.”

Teeth: Scars being solved!

Describing what he called the “final drop in the bucket of how you are going to fall apart,” Alan Mann, professor of anthropology at Princeton University, focused on the “wisdom tooth,” or third molar, which often jams instead of emerging in young adulthood.

This is supposedly the time when teenagers get “wisdom,” but instead a pain gnaws their jaw!

Teeth are the opening gambit of the digestive system. The front teeth are shaped to tear away food and the back teeth shaped for grinding and shearing food before swallowing and digestion.

The emergence of human teeth is tightly choreographed: The baby teeth start appearing at roughly age one, and later are replaced by the adult teeth as the mouth enlarges. The tough diets of our ancestors quickly wore the teeth, so it made sense for a brand-new molar — the third — to emerge after puberty.

That midget brain fitted quite nicely above the triplet of molars in this portrayal of Sahelanthropus tchadensis, a human ancestor from about 7 million years ago. Rollover to see a modern head, where the brain has moved up and forward, leaving less space for three molars.

Credit: dctim1 and illuminaut

But once the human brain expanded, the brain moved from behind the face to above it, leaving less room for the teeth, and the result, often, was an impacted wisdom tooth.

And the big brain (it’s three times as big as our ancestors’) Mann says, is the ultimate reason why wisdom teeth get stuck.

That’s the evolutionary bad news. The good news is that a random mutation thousands of years ago that prevents the third molar from hardening is spreading as evolution selects against wisdom teeth. Among some populations, 40 percent of people lack at least one third molar.

Impacted wisdom teeth are seldom fatal, so why would they shape our evolution? To answer, Mann offers this scenario: “One evening, a person who had chronic pain from an impacted tooth is asked, ‘How about a bout of reproduction, dear?” and responds, ‘Not tonight, my jaw is killing me.’” The result, he says, could be fewer offspring for the unlucky adults with impacted third molars.

So evolution is not just a source of scars, but also of solace, Mann says. “In the course of human evolution, as the amount of space [in the jaw] became smaller, a random mutation had selective value, and its frequency increased over time. But the third molar remains a scar of human evolution when dental technology [surgery] is not available.”

Birth: the most perilous escape

“If you want an example of something that is not intelligently designed, think about the crazy, tricky, complicated, uncomfortable way we have babies,” says Karen Rosenberg, chair of anthropology at the University of Delaware. “Childbirth is a time in the life cycle where women and babies are under increased risk of injury or death.”

These difficulties “go way back in evolutionary history, possibly back to the beginning of bipedalism,” she says. Our ancestors, after all, lived in trees and were much better at climbing than walking, which they did on all fours.

Efficient upright walking requires narrow hips, which shrinks the birth canal in the pelvis. But the birth canal must still accommodate that pesky-big human head.

Culture is critical during birth, Rosenberg says. After the head rotates, “the baby usually turns and emerges facing back. And so there is a benefit to having someone there to catch the baby.”

Photo: UNAMID

Young women learn how pregnancy affects the pelvis at the School for Midwifes in Elfasher, Sudan, as they prepare to assist in childbirth.

Attended birth is essentially unknown among our relatives, Rosenberg says. “Other primates give birth without assistance, in isolation. Humans give birth socially, and midwives around the world know all kinds of different things that ameliorate the risk. We are able to mitigate the risks because we are cultural animals; we have someone there to help when in labor.”

The result is a positive feedback among brain size, intelligence and culture, Rosenberg says. “The fact that we give birth in such a risky way speaks to the benefit accrued by having such a large brain. We are able to have culture because we have a large brain, and are able to have a large brain because we ameliorate the risks of childbirth culturally.” Even though childbirth remains hazardous, “This tells us how beneficial it is to have large brain, and the complex behavior we have as humans.”

The benefits of culture continue past birth, Rosenberg says. “It’s because we are cultural animals that we can take care of a baby that is born earlier, wrap it in a blanket, use a cradle board to prevent injury to the neck.”

All story long, we have been hearing complaints about the jury-rigged equipment we inherited from our ancestors — feet with too many bones, unstable spines, and teeth that get stuck instead of emerging on schedule. But “childbirth is not a scar of evolution,” Rosenberg insists. “The evolution of a rotating head during birth allowed this continual increase in brain size; we came to a point where the brain could not get bigger” unless we had culture to support the mother and infant. “Childbirth is an ancient and fundamental part of what makes us human.”

Congratulations to our winners!

Scientific imagery, of course, is intended to help scientists. It is a critical form of data in many fields and can yield important and sometimes striking insights into nature and the way things work.

But the pictures and other images of science can also have remarkable aesthetic qualities that the non-scientist can appreciate. That has been the philosophy of our Cool Science Image feature, published on this site for 17 years.

Three years ago, as an experiment, The Why Files held its first Cool Science Image contest. Limited to Why Files headquarters, the University of Wisconsin-Madison, the contest yielded more than 60 entries.The next year 84 Badgers entered the competition. This year, there were 105 submissions. This year also sees a new sponsor for the contest. We welcome the interest and generous support from Madison-based Promega Corp.

Choosing the winners was difficult, but our judges narrowed the field to ten winners, included in this slide show.

The experiment, we think, has been a success. Our goal now is to continue this as an annual event. We hope to grow the contest and help bring the visual beauty of science to a larger audience, an aspiration that can make all of us winners.

*If you wish to repost any of these images, please acknowledge the University of Wisconsin-Madison and include a link to this site. We would also appreciate notification of repostings.

Do you love roads or hate them? If you’re an environmentalist, chances are you’re at least highly skeptical. Roads are famous for bringing settlers, forest destruction and farms to natural areas that are often inappropriate for sustainable agriculture.

But the agricultural industry, and people who promote farming as an antidote to hunger and poverty, see another side to roads. Farmers who want to do more than feed their families need good roads to bring in advisors, fertilizer and seeds, and take crops to market.

Roads that are muddy or impassable can make transport so expensive that cash cropping makes no sense.

This week, the journal Nature prints a proposal to square this circle by developing a system to chart where roads are beneficial, and where they are harmful. As the authors wrote, “We propose that environmental scientists, planners, road engineers and other stakeholders carry out a global ‘road-zoning’ project to map areas that should remain road-free and those in which transport urgently needs improving.”

We emailed corresponding author William Laurance, a conservation biologist at James Cook University in Australia, to ask if the idea was “pie in the sky.” Not so, he wrote. “What we’re hoping to see produced is a tool that anyone can use to prioritize where and where not to put roads. Some stakeholders and nations will hopefully use it, but of course not everyone will.”

Although rampant road-building in tropical forests has lead to significant forest destruction, “The situation is slowly improving,” Laurence wrote to us.  “Big highways tend to be more controlled than secondary and tertiary roads. Many of these smaller roads are being created illegally in remote areas, and that’s something that needs to be cracked down on.”

Roads really matter, says Lisa Naughton, a professor of geography at the University of Wisconsin-Madison, who studies development and conservation in the tropics. When the Interoceanic Highway was recently completed in the Peruvian Amazon, she says, “It utterly transformed the relationship between people, land and forests. The long-term efforts of Peruvian conservationists to promote sustainable agroforestry and non-timber forest-product harvest (such as Brazil nuts) were rapidly undermined as the road brought in large-scale agriculture, and deforestation has accelerated.”

Building in the zone

Rather than establish mandatory zoning, Laurance envisions a map that helps planners, politicians, agricultural interests and conservationists guide development while protecting indigenous lands, biodiversity hotspots and other sensitive areas.

The balanced approach, he says, “is a potential advantage … . We’re not saying to simply stop all road building. We’re saying let’s stop some of the environmentally destructive roads … while at the same time focusing road building where it’s likely to have the biggest economic and social benefits.”

According to projections, the demand for food will soar by 2050, due to a rising population with a growing desire for meat. According to the Laurance study, an extra 1 billion hectares (which happens to be the size of Canada!) will be needed for crops and grazing land. Much of that will have to take place on wild land.

But boosting agricultural productivity could supply some of this food, slowing the destruction of wild lands and wild creatures.

Roads: Farmers’ best friend?

It’s impossible to imagine advanced agriculture in developed countries without good roads. Do roads play the same role in developing nations? “It’s funny—this is one of those ideas that seems to be widely accepted but doesn’t have a lot of formal evidence,” wrote Laurance. “I know because we’ve looked. … In scientific terms, there is a scattering of papers and books that use econometric approaches to argue that road improvements benefit agriculture — reducing waste, increasing market access and improving profitability. But … there doesn’t seem to be much debate about this among those who study such things.”

Even if zoning for roads makes sense, practically speaking, could it work? Although national governments “have legal sovereignty over their lands, there are very powerful economic forces at work to promote road building — some of which are clearly inadvisable environmentally,” Laurance responded. The road-zoning scheme “could be used by governments and also conservation groups and other stakeholders to facilitate road planning.”

“The call for ecologically-informed road zoning is appropriate but faces major political challenges,” says Naughton, director of the Land Tenure Center at UW-Madison. “Perhaps some of the major roads funded by multi-lateral development agencies can be planned to lower social and biodiversity impacts. But there is ever more private and unilateral international funding available for road-building. More fundamentally, road-building has great political importance in a place like the Amazon — even if a road makes little economic sense, there are often strong political incentives to build it.”

But Laurance notes that, in the face of a proposal to push a road through a wilderness, “With a good road-zoning scheme, you could say, ‘Hold on a minute — that’s an environmental red-zone, the last place you’d want to construct a road. Let’s consider another route or perhaps even forego a new road altogether. Roads profoundly influence the spatial footprint of human activities, and so it’s crucial to focus explicitly on them.”

On Feb. 28, 2013, the earth opened up in Seffner, Florida, and Jeffrey Bush fell to his death. Local authorities decided they could not safely recover the body: excavating the rock and sand would cause more collapse and more danger.

Photo: Daily News

Jeremy Bush, who tried to save his brother, Jeff, says his parents are ‘going through hell’ after Jeff died in a Florida sinkhole Feb. 28.

Then, on March 12, an Illinois golfer fell through a sinkhole — possibly associated with an abandoned mine — on the 14th hole. Mark Mihal, 43, survived an 18-foot fall with just a sore shoulder, after his golfing companions fished him out with a rope.

The incidents are graphic examples of the dangers of taking geology for granted. Earth is not always as solid as a rock.

In large parts of Florida and other states, a soluble subsurface geology called karst is conducive to sinkholes. Karst occurs in rock dominated by gypsum, limestone or salt — which can dissolve, leaving underground streams and cavities.

The U.S. Geological Survey says about 20 percent of the United States overlies karst terrain; the worst sinkhole damage occurs in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania.

Classically, sinkholes occur in locations where water, unable to flow laterally, percolates through soluble rock, creating caverns and cavities. Often, the surface will gradually subside, causing a cover-subsidence sinkhole. And as we’ll see, other forms of collapse are popularly called sinkholes as well.

More rarely and dramatically, when the roof span becomes too large, the outcome is a “cavity collapse” sinkhole. That was apparently the fatal flaw in Seffner, Fla.

Subsidence can also occur

In cold winters in the strawberry fields east of Tampa, Fla., farmers pump groundwater so they can spray their crops to prevent freezing. “In 2010, this opened about 140 sinkholes,” says Mark Stewart, professor of geology at the University of South Florida. “Most of them did not damage homes, but several did, and there was some damage to an interstate highway.”

Because wells are a known trigger for sinkholes, many subdivisions in the sinkhole-prone North Tampa area prohibit private wells, Stewart says. “You can’t have a well for irrigation or water supply. You have to be on city water.”

The many sides of subsidence

If removing water can cause collapses, so can adding water through leaking water pipes, sewers and storms. Storm runoff was blamed for a dramatic hole-in-the-ground that formed in Guatemala City, Guatemala, in 2010. The city is built on a volcanic ash plateau, and groundwater, sewer systems and storm drains all feed the fragile ash. “The result is erosion of the material, which creates cavities that can collapse,” says Stewart. “It can be really catastrophic.”

In New Orleans and other river deltas, subsidence occurs as organic material in soil decomposes and new sediment, which would sustain ground level, is blocked behind levees. Parts of the Sacramento-San Joaquin river delta in California have fallen to more than 15 feet below sea level.

Sinkholes can result when industrial and water-storage ponds get so heavy that they trigger a collapse.

Full-size diagram here: Pennsylvania Department of Environmental Protection

Pennsylvania, riddled with expired coal mines, has major problems with subsidence.

Minding mining

And then there is mining, which is a major cause of subsidence in Pennsylvania, West Virginia and Kentucky. Those states have about 60 percent of U.S. abandoned coal mines; overall, the nation has about 14,000 active mines, and up to 500,000 abandoned mines of all sorts.

U.S. Geological Survey

A collapse at the Retsof mine in Upstate New York had broad repercussions for the economy, landscape and groundwater.

In 1994, an earthquake collapsed a 500-foot square chunk of roof rock above a huge salt mine south of Rochester, N.Y., and water began flooding in. Since the Retsof mine opened in 1885, it had grown into the world’s second-largest salt mine, covering 10 square miles.

Within 21 months, the mine was inundated and closed. Water levels dropped in wells as far as 10 miles away, and two sinkholes formed, each about 50 by 200 feet. Further subsidence is expected as groundwater dissolves more salt; eventually, as the mine roof continues its slow-motion collapse, the ground above the mine is expected to fall eight or nine feet.

Finding that sinking feeling

Sinkholes can be surprising, but they don’t appear at random. In sinkhole-prone states, state geological survey maps should provide at least a general guide to risk; the USGS also has a national mapping facility.

Although a cover-collapse sinkhole may come without warning, experts say people in karst terrain should look for these signs of subsidence:

Recognizing safe building sites in areas prone to sinkholes entails a multipronged approach, writes sinkhole expert Francisco Gutiérrez, professor of geology at the University of Zaragoza, Spain.

Yet as the recent Florida case shows, cover-collapse sinkholes usually come out of the blue. You might think that a state laced with sinkholes would want to zone development away from danger, but the Florida Board of Realtors “is not interested in any kind of hazard zoning,” Stewart says. “To get a mortgage, you must have homeowner’s insurance, and then it would be extraordinarily difficult to get insurance, so banks would be very hesitant to give mortgages, and that would greatly affect property values” in sinkhole areas. Rather than blacklisting areas likely to subside or collapse, the trend is to “leave the risk to the homeowner.”

Better take out some insurance

The Florida insurance industry, buffeted by sinkhole claims, has pushed through a law requiring cases to be settled by arbitration, rather in court, Stewart says. “There was a substantial loss to the insurance industry, so the legislation was changed.”

Homeowner’s insurance in Florida does cover sinkholes, he says, but not other causes of subsidence, which can cause slow-mo damage. Insurance companies “typically call in a geotechnical firm to do an investigation. In many, many cases, it’s not due to a sinkhole, so the homeowner hires their own geotechnical firm, which says it is, and the issue goes to arbitration.”

One source of data, ground penetrating radar, which reflects off different layers in the subsurface, “can be interpreted over a broad range by experts,” says Stewart. “The level of professionalism among people in the industry has not been at its highest level. Until recently there was a lot of money to be made by lawyers, geotechnical firms and the insurance industry.”

In 2010 alone, there were more than 6,600 sinkhole claims in Florida, Stewart says. “It’s not possible to estimate how many were legitimate. There are geotechnical experts on both sides, so there is no final determination whether it was a sinkhole.”

In a sense, sinkholes, like lightning are frightening natural phenomena that seem to strike from nowhere. “A hole opened under the bedroom and the man went down and was buried while sleeping,” says Stewart. “The Earth isn’t supposed to open up under you. It’s like shark attacks; they get press even though they are extraordinarily rare. Because of the emotional attachment, people see too much risk where there is in reality low risk.”

It was a mystery of nature even before Charles Darwin reached the Falklands Islands in the South Atlantic: How did the Falklands Islands wolf, the only resident mammal, reach the islands, about 460 kilometers off the Argentine shore?

The great naturalist and writer wisely wondered what was weird with the wolf:

After Darwin left, whalers, sealers and farmers hunted and poisoned the Falklands wolf to extinction.

Nobody thought the wolf, AKA Dusicyon australis, had crossed the strait. Did it cross on a raft made of trees, walk on the winter ice, or catch a ferry ride from obliging people now lost to history?

The question of colonization of remote islands recurs often in natural history: The journeys of plants, parasites, people and other mammals beg for explanation, especially on remote islands like the Falklands.

Now, a team from the University of Adelaide in Australia has combined forensic genetics with paleogeography to come up with an answer, based on shifting sea levels and the wolf’s relationships to relatives on the mainland.

Welcome the newbie!

The study began by analyzing genetic sequences to identify when the Falklands wolf split off from its last common ancestor, a now-extinct mainland fox called Dusicyon avus. Logically, the wolf made its crossing after it diverged from its ancestor.

Instead of dating the fork in the road with standard rates of mutation, the researchers carbon-dated the ancestor’s remains. After counting the genetic differences between the wolf and the fox, they arrived at a rate of molecular changes per year for those animals, at that time, says senior author Alan Cooper of the Australian Centre for Ancient DNA. “We think this is a much better approach than standard mutation rates. This is quite an important difference from other studies.”

Previously, scientists concluded that the wolf had reached the Falklands about 330,000 years ago, but the new analysis — focusing on a different last common ancestor — pointed toward a much more recent arrival, about 16,000 years ago.

That was during the height of the Wisconsin ice age, when ice sheets, especially on Antarctica, locked up ocean water, causing sea level to fall. That exposed “land bridges” linking islands and continents.

As the ocean surface declined about 130 meters, the strait separating the Falklands (known in Argentina as the Malvinas Islands) narrowed to a couple of dozen kilometers. Presumably this water froze during some winters, and the wolf either roamed across or rafted on icebergs.

It’s possible that other mammals reached the Falklands but left no traces — or that the wolf was the only mammal to cross the strait. “The wolves were after marine resources, like seals, penguins and seabirds, on the edge of the ice,” says Cooper. “Other mammals such as rodents, which are common in South America, were not interested in crossing 20 to 30 kilometers of ice, as there is no food or habitat.”

I go, you stay

The study brings into focus the role of climate and sea level in colonizing remote islands. “Strangely enough,” says Cooper, the role of sea level change “was the key observation that led Alfred Russel Wallace to discover evolution independently from Darwin.”

In 1858, Wallace, a naturalist, mailed his theory of natural selection to Darwin, who recognized it as strikingly similar to his own, unpublished theory. Darwin helped arrange a simultaneous reading of the theories at a scientific meeting in 1859.

Wallace, who was still collecting specimens in the southwest Pacific, noted that similar animals lived on islands that were separated by shallow seas. But when he looked at organisms on opposite sides of what’s now called the “Wallace line,” he saw that animals like those in Australia lived to the east. The animals living to the west were related to those living in Asia.

And dividing the two regions is the Lombok Strait, which was deep enough to remain open during glacial times, and too warm to freeze over, even during the Ice Ages. Although Darwin is rightly credited as the originator of evolution through natural selection, “he didn’t really seem to grasp the role of sea level change to the same degree,” says Cooper.

But let’s give Darwin the last word: The Falklands wolf DNA used in the study came from a specimen Darwin collected in 1834.