EXPLAINED

Giant squid?
This week, a British journal published the first-ever pictures of a giant squid alive in its natural habitat. A pair of Japanese researchers set up an apparatus that photographed the creature as it wrapped its tentacles around some bait attached to a deep-sea camera. How did the giant squid remain elusive for so long?

The difficulty of underwater exploration. The giant squid may be no harder to find than any other animal that lives at the bottom of the ocean. Submersibles that travel thousands of feet underwater have provided scientists with only a limited view of deep-sea life. Cameras can see only what's within range of an artificial light, and light can scare off some dark-adapted critters. Plenty of deep-sea animals other than giant squid have shown up in fishing nets without having been captured on film in their natural environment.

The giant squid seems especially mysterious for a couple of reasons. First of all, its incredible size—giant squids can be 40 feet long or more—makes it hard to believe that it can't be seen alive. Second, dead giant squids surface with surprising regularity. In the last few years, there's been a dramatic increase in the number of giant squid carcasses that have been discovered. So, why is it so hard to find a living giant squid when the dead ones are a dime a dozen?

For one, we don't really know where and how giant squid live. Specimens have been found all over the world, but it's not clear if they have regular migration patterns. We know sperm whales eat giant squid—remains have been found in the whales' stomachs—so some researchers have tracked the predators to find the prey. The Japanese researchers looked for the giant squid where sperm whales were known to congregate. Their camera-on-a-rope technique wasn't particularly innovative. (More adventuresome researchers have attached cameras to the sperm whales, for example.) Giant squid experts think they just got lucky.

What's with all the giant squid carcasses? Dead giant squids may be more buoyant than the carcasses of other deep-sea creatures because they have an unusually high concentration of ammonium ions. Since the ammonium is lighter than seawater, the carcasses tend to float, making them easy to spot. (Giant squids use the ammonium to keep from sinking while they're alive, too.) It's less clear why so many have turned up in the last few years. One theory suggests that an increase in deep-sea fishing—of orange roughy in particular—has disturbed the giant-squid habitat. Others say that the squid deaths have been caused by underwater seismic surveys using air guns. Or it could be global warming.

What's the difference between squid and giant squid? The giant squid isn't just a big ol' version of a regular squid—it has its own genus, called Architeuthis. (There may be several species of giant squid, but no one knows for sure.) The lesser-known "colossal squid," of the genus Mesonychoteuthis, may be even bigger and nastier than the giant squid. It has a larger beak than the giant squid and has hooks on its tentacles. While a few specimens of colossal squids have been discovered, no one has yet seen one in its natural habitat.



How do you measure sea level?
The mayor of New Orleans ordered mandatory evacuations over the weekend to protect residents from Hurricane Katrina. According to an emergency management expert, New Orleans is particularly vulnerable to flooding because parts of the city are 10 feet below sea level. How do you measure sea level?

With satellites and tide gauges. Satellites can record the level of oceans around the globe, while tide gauges are used to measure the height of water with respect to a fixed, nearby point on land. Oceanographers combine data from satellites and tide gauges to study global effects, like the rise in average sea level that results from climate change. But specific information about local features, like the relative depth of certain parts of New Orleans, derives from specific tidal-gauge readings. (Land can also rise and fall over long time periods, so changes in land level must also be taken into account.)

The simplest kind of gauge measures the height of a float in still water. A submerged column surrounds the float and prevents choppy waves from creating sudden fluctuations in sea level. The gauge keeps track of the float as it drifts up and down throughout the day and records its height (with respect to a land-based bench mark) at regular intervals. More advanced instruments use sound waves or pressure to measure the same thing.

Stable features such as underwater mountains can affect the local sea level. So can systematic variations in water temperature, air temperature, and currents. Topographical features and predictable weather patterns cause parts of the Atlantic Ocean, for instance, to be 40 centimeters lower than parts of the Pacific Ocean. (The Panama Canal spans a sea level difference of 20 centimeters.)

Changing tides and weather conditions can also create dips and swells in local tide-gauge readings. Since local readings can fluctuate so rapidly, most descriptions of "sea level" refer to an average value measured across many years. First, readings are collected over an interval that takes into account regular tidal patterns. (A standard 19-year cycle covers a full cycle of Earth-Moon and Earth-Sun interactions.) Then researchers filter out some of the short-term influences on the data, like extreme weather patterns and storm surges. The readings are averaged together to produce a "mean sea level" reading for a specific station or group of stations in a region. As determined by nearby tide gauges, much of New Orleans sits below the mean local sea level.

If New Orleans is below sea level, why isn't it underwater? Because it's protected by natural and artificial barriers. The city sits on the banks of the Mississippi, where sediment from the river had created areas of elevated land called "natural levees." New Orleans' earliest buildings sat on top of these levees, but as the population grew, houses were built farther inland at lower elevations. To create usable land, water had to be pumped out of the area, which in turn caused the ground to sink even lower. It's possible for part of New Orleans to exist below sea level because the levees that surround the city protect it (most of the time) from floods.



Who decides to wake up the president?

News of the death of Saudi Arabia's King Fahd reached the White House at 2:30 Monday morning. According to spokesman Scott McClellan, the president wasn't informed until he showed up for work at 7 a.m. When something happens in the middle of the night, who decides whether the president should get out of bed?

It varies from president to president, but the task usually falls to the national security adviser or the chief of staff. In the White House, a small team of "watch officers"—drawn from the CIA, the military, and the State Department—keeps an eye on incoming news and intelligence reports 24 hours a day. If something important comes up during the graveyard shift, the watch officer in charge gets in contact with the national security adviser or chief of staff, either via their deputies or a with a direct phone call. The watch officers typically have standing instructions on what sort of news merits a wake-up; President Bush's chief of staff, Andrew Card, for example, has said he wants to be awakened for any overseas incident in which Americans are killed.

This procedure has been in place only since 1961, when John F. Kennedy ordered the construction of a permanent monitoring station on the site of what was once the West Wing bowling alley. (Before 1961, 24-hour war rooms were constructed and dismantled as needed.) The new facility became known as the "situation room."

It's not that unusual for a president to be awakened with news from the situation room. President Bush was alerted when a U.S. spy plane made an emergency landing in China in 2001 and for a deadly suicide bombing in Jerusalem in 2002, among many similar events.*

But history remembers a snoozing president more than an alert one. When Henry Kissinger learned of a menacing letter from the Soviet premier in 1973, the White House chief of staff advised him not to wake up the president. (Former aides have said that Nixon, who was distraught over his domestic scandals, had drunk himself into a stupor by 10 the night before.)

Ronald Reagan, who famously slept during Cabinet meetings, also snoozed through two overseas military encounters. In 1981, his counselor Edwin Meese called a 3 a.m. staff meeting after learning that U.S. fighter jets had shot down a pair of Libyan planes earlier that night. They decided against calling Reagan in his Los Angeles hotel room. And in 1985, Reagan's National Security Adviser Robert McFarlane chose not to wake him when an American soldier was shot and killed in East Germany. (Reagan's reputation for snoozing even invited a protest: In 1983, steel and auto workers marched on the White House at 4 a.m. to "wake up the president" to the effects of his economic policy. Reagan said he slept through that, too.)

When George H. W. Bush took office, he announced that he'd be a "wake me, shake me" president, ready to spring into action in the middle of the night. His bedtime during the first Gulf War was 10:30, but National Security Adviser Brent Scowcroft would rouse him with important news.

Bill Clinton received wake-up calls from Deputy National Security Adviser James Steinberg when necessary, but he slept through the racket when a gunman fired half a dozen shots at the White House one night in December of 1994. He also slumbered through congratulatory phone calls from foreign leaders after he won the election in 1992.


What Do Bombs Smell Like? And how do they train dogs to sniff them out?

How do dogs learn to smell bombs?

Classical conditioning techniques using food rewards and toys. In the United States, the Bureau of Alcohol, Tobacco, Firearms and Explosives, Customs and Border Protection, and private dog trainers teach bomb-sniffing dogs. The preferred starting age is between 8 months and 22 months, and the Labrador retriever is a favored breed due to its lack of aggression in high-intensity situations.

The training programs derive many of their techniques from narcotics detection. During the ATF's 10-week program, a dog is exposed to an explosive up to 120 times a day, in amounts ranging from 1,000 pounds to 1 gram. In early phases of training, the dog is told to sit each time he finds the odor—that becomes the signal he uses to alert his handler when a bomb is present. The dog is fed only when in the presence of the explosive. Using a food reward instead of praise and play prevents an exclusive bond between dog and handler, which might prevent the dog from working well with others.

One upper-level training scenario uses a rotating wheel with slots for four containers. Some of the containers are empty; others hold explosives, a distracting object such as food, or an explosive combined with a distracting odor. By using the training wheel, the dog learns to ignore food in favor of explosives.

Some agencies avoid mixing food with work and infuse dog toys with explosive odors instead. The dogs learn to root out hidden explosives by simply playing fetch. This approach requires dogs that have a strong natural inclination for play. It also cements a canine-trainer bond, restricting the dog to working with only one handler.

The dog must learn to recognize thousands of active ingredients that might be used in an explosive. Trainers expose the canine to signature compounds that are found in many different types of explosives. In this way, a dog can be trained to detect all manner of bombs by memorizing a dozen or so smells. According to the Army's military working-dog training manual, canines are trained using dynamite, TOVEX, TNT, C-4 plastic explosives, detonating cord, and potassium chlorate, among other explosives.

Some bomb components are more odoriferous than others. C-4 has an incredibly strong scent; it's followed in decreasing order of smelliness by dynamite, TOVEX, detonating cord, and TNT.




Richter, Gerhard
Annunciation after Titian
1973
Oil on linen
49 3/8" x 6' 6 7/8" (125.4 x 200.3 cm)
Hirshhorn Museum and Sculpture Garden, Washington