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A model of estimated fault slip for the March 2011 Japanese earthquake. (Credit: Mark Simons/Caltech Seismological Laboratory )

Scientists knew something was wrong with their understanding of the offshore fault that was the source of the March 11 earthquake in Japan almost immediately after the shaking began. That part of the ocean floor, where the ocean plate subducts beneath Japan, was supposed to be simple and uniform, sometimes sticking and building up stress that should have released in segments, creating large (magnitude 7 or 8 ) earthquakes every few decades or centuries or so. A magnitude 9 quake was not possible, so they thought.

In the months that have followed, geophysicists have been looking into exactly what happened—aided by what might be the best earthquake sensor network on the planet, with hundreds of GPS data recorders documenting movements on land and the sea floor, along with other sensors that measured wave heights from the tsunami. And now some of these researchers have published early results (which are freely available online from the journal Science) from what one scientist called “the best recorded earthquake ever.” Here are a few of the highlights:

1 ) The geologic fault where the Japanese earthquake originated is far more complex than scientists once thought. Geophysicists suspect that a bit of the plate that is sinking beneath Japan, perhaps a seamount, had stuck—for reasons still unknown—causing strain to slowly build up over hundreds of years. Some researchers had previously assumed that the area had been slowly slipping without causing any quakes, but that was not correct.

2 ) About 250 kilometers of fault experienced significant slip during the event, about half the length of what would be expected in an earthquake of this magnitude. And the the most slip—30 meters or more—occurred in an even smaller area, only 50 to 100 kilometers long. Nothing like that had ever been recorded before. These realizations call into question previous conclusions that the fault nearer Tokyo could not create a similarly sized earthquake. “It is important to note that we are not predicting an earthquake [for the fault closer to Tokyo],” says Caltech geophysicist Mark Simons. “However, we do not have data on the area, and therefore should focus attention there, given its proximity to Tokyo.”

3 ) Different parts of the fault produced high- and low-frequency waves. High-frequency waves, which are generated by areas under the highest levels of stress, came from the edges of the area of slip, not where the fault began its break as seismologists had previously assumed. If the fault were compared with a piece of paper being torn in half, “the highest amounts of stress aren’t found where the paper has just ripped, but rather right where the paper has not yet been torn,” Simons says.

It’s somewhat heartening to realize that out of the death and destruction of the quake and tsunami is coming even better earthquake knowledge that will help us better prepare for—and perhaps one day even predict—earthquakes. For almost all of humankind’s existence, all we’ve been able to do in the face of earthquakes, tsunamis and other natural events is to clean up whatever is left after the disaster has hit. But science has changed much of that, and now we can plan and prepare for the inevitable and often stave off the worst possible outcomes.

Black-footed ferrets at the National Zoo (Credit: Mehgan Murphy, Smithsonian's National Zoo)

In honor of today, Endangered Species Day, I put together a photo essay on North America’s most endangered animals. To get a list of 10, I started by searching through the IUCN Red List of Threatened Species, which is probably the most reliable source of data on this topic. With hundreds of endangered animals, I had to limit my search to species that were Critically Endangered or Extinct in the Wild. Merely “Endangered” wasn’t enough. And so I had to leave out one of the cutest, and most familiar, endangered animals of North America: the black-footed ferret.

There were once tens of thousands of black-footed ferrets living on Western prairies. But disease, habitat destruction and efforts to eliminate their main prey, the pesky prairie dog, drove them nearly to extinction. By 1986, the only black-footed ferret survivors lived in captivity. But reintroduction efforts, which began in 1991, have been successful at about half of the 19 sites where they have been tried, and the wild population now numbers around 750 animals. The ultimate goal is to have about 1,500 ferrets and at least 10 populations with 30 or more breeding adults.

When I looking into the subject of endangered animals, I thought that whatever I wrote was going to be incredibly depressing. But instead, I found so many reasons to be hopeful. Identifying the fact that a species is dwindling in numbers isn’t the end. That recognition often prompts scientists, conservationists, government officials and the public to take action. And so we have people scouring Panama for new species of frogs, hoping to save them before a deadly fungus reaches their home, and others rearing all kinds of critters in captivity—from tree snails to condors—in an effort to preserve them from extinction.

What would you do to help save a species from disappearing forever?

A mummified princess from Thebes (known as Luxor during her time) is the earliest person known to have had coronary heart disease (courtesy of flickr user Rita Willaert)

You might be under the impression that hardening of the arteries, a.k.a. atherosclerosis, is a modern problem. That our diets, rich in animal fats and processed foods, are the problem, and if we only ate like humans used to not so long ago, we’d have no need for bypass surgeries and no one would ever die of a heart attack. But atherosclerosis is common in Egyptian mummies, say scientists who imaged dozens in Egypt, going as far back as 1550 B.C. (Their study, recently published in the journal Cardiovascular Imaging, was presented at the International Conference of Non-Invasive Cardiovascular Imaging earlier this week.)

The researchers created CT scans of 52 ancient Egyptian mummies at the National Museum of Antiquities in Cairo (the mummies couldn’t leave, so the scans were done at the museum). They could see arteries in 44 of the mummies. Of those, 20 had calcification, a marker for atherosclerosis, in their arteries, and in three of the mummies that calcification could be seen in coronary arteries.

Calcification in the right (RCA) and left (LCA) coronary arteries appears white in this CT scan (courtesy of the European Society of Cardiology)

The mummies with signs of atherosclerosis tended to be those that had lived the longest; they averaged 45 years old. One of the three with coronary heart disease was the princess Ahmose-Meryet-Amon, who lived in Thebes around 1580 to 1530 B.C. and died in her 40s; two of her three main coronary arteries were blocked. If she had lived today, “she would have needed bypass surgery,” said one of the study’s co-authors, Gregory Thomas of the University of California, Irvine. She is now known as the earliest person in history to have suffered from coronary heart disease.

At the time when the princess lived, the Egyptian diet consisted of fruit and vegetables, bread, beer and a little domesticated, lean meat, which may sound like a doctor’s recommendation for how to avoid the very problem the princess had. So how did her arteries end up with so much calcification? The researchers have a couple of theories. Parasitic infections were common in ancient Egypt, and the resulting inflammatory response may have predisposed her body to atherosclerosis, much as HIV appears to do so today. Foods during that time were often preserved in salt, which could have had an adverse effect. Or the princess may have eaten a different diet than the average Egyptian; as a royal, she could have feasted on luxury foods like meat, cheese and butter, the very items that heart doctors tell us to avoid.

A guanaco in Chile (courtesy of flickr user Trabita)

Scientists have traditionally labelled species of hoofed mammals as either “migratory,” meaning they travel long distances from one place to another and back again, or “non-migratory” and based conservation plans on those labels. But now researchers at the Smithsonian Conservation Biology Institute and elsewhere are adding a third category, “nomadic.” And in their new study, published in Global Ecology and Biogeography, the scientists show that patterns in vegetation across a species’ range determine whether and how it moves.

The researchers looked at tracking data from four hoofed mammal species: guanaco, a llama-like creature from Argentina; barren-ground caribou in the Alaskan and Canadian Arctic; moose in Massachusetts; and Mongolian gazelle. They then compared this data with a 25-year set of satellite data showing how the landscapes in these places changed from season to season and year to year.

Moose were sedentary and stayed mostly in a small home range (non-migratory), while the guanaco ventured a bit farther (semi-migratory). The caribou had a long migration, covering hundreds of kilometers and crossing the U.S.-Canada border (migratory). Though the Mongolian gazelle also traveled hundreds of kilometers, they didn’t fit the standard “migratory” label, the researchers found. “When we put radio collars on [the gazelle],” said Thomas Mueller of SCBI, “we were surprised to discover that they go off individually in different directions.” Mueller and his colleagues labelled this third category as “nomadic.”

They also found a correlation between the variety in a landscape and how a species moved. The guanaco and moose, which moved the least, lived in areas where the vegetation had little variability. The caribou moved long distances in a coordinated manner, following the patterns of vegetation productivity, going where they’d find the best meal. The vegetation is less predictable in the landscape where the Mongolian gazelle live, however, and so their movements are also less predictable.

The findings have implications for the conservation of migrating animals. Traditional strategies run on the assumption that the critters move from one place to another with seasonal regularity, but this study shows that that’s not always the case.

The Great Barrier Reef (photo courtesy of flickr user Barbara Rich)

As we pump more and more carbon dioxide into the atmosphere, the ocean absorbs some of it. And as CO2 dissolves, it makes the oceans’ water more and more acidic. This acidification creates plenty of potential problems for life in the oceans, but corals might have it the worst. If the ocean becomes too acidic they won’t be able to create their calcified skeletons; the chemical reaction they rely on slows down under lower pH levels . But scientists in Australia say that the situation is more dire than expected. In their study, published in Ecology Letters, they show that higher CO2 levels may be give seaweed an advantage in a competition with coral.

Corals compete with seaweeds for space on the reef. When corals are healthy, the coral–seaweed competition reaches a balance. But if the corals aren’t doing so well because of something like eutrophication, then seaweed can take over.

In this new study, the researchers studied the coral-seaweed battle in miniature, setting up bits of each (Acropora intermedia, the most common hard coral in the Great Barrier Reef, and Lobophora papenfussii, an abundant reef seaweed) in tanks in the lab. Each tank had one of four CO2 levels in the air above it, resulting in four different pH levels: 300 parts per million (equivalent to pre-industrial CO2 and pH levels), 400 ppm (present-day), 560 ppm (mid-21st-century estimate) and 1140 ppm (late-21st-century estimate).

When there was no seaweed, the corals survived. But with its competitor present, the corals declined under each scenario. However, the decline was worse under higher CO2 levels, to the point where under the late-21st-century scenario, there was no living coral left after a mere three weeks.

“Our results suggest that coral (Acropora) reefs may become increasingly susceptible to seaweed proliferation under ocean acidification,” the researchers write. This area of research is still in the early stages and this experiment was a simplification of the coral–seaweed dynamic (there were only two species tested, for example, and plant-eating fish were left out of the equation), but it may provide even more reason to worry about the future of the coral reefs.