What is it? A beaded necklace? Red blood cells? No, it’s the Portuguese Man o’War (Physalia physalis), magnified 30 times. Though it resembles a jellyfish, the Portuguese Man o’War is a siphonophore, a colony of organisms that work together. The sting of the venom in the tentacles’ nematocysysts is incredibly painful, though rarely deadly. This photo, taken by Alvaro Migotto of the University of São Paulo in Brazil, won 6th prize in the 2009 Olympus BioScapes Interational Digital Imaging Competition.
Notorious for its painful, powerful sting, the Portuguese Man o’ War has a gas-filled floating chamber that supports the tentacles, which bear sting cells. Shown are the pink batteries of stinging cells and a delicate muscular band responsible for the high contractibility of the tentacles.
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My colleague Megan Gambino visited the Smithsonian Tropical Research Institute earlier this year to watch coral spawn. A report appears in the December issue of the magazine, and she also blogged about the experience over at Around the Mall. We asked her if anything interesting got left out of her previous reports. Yes, lots, she replied, and wrote this:
This past September, I joined marine scientist Nancy Knowlton, of the National Museum of Natural History; her colleague Don Levitan, of Florida State University; and a crew of research divers on their annual coral spawning trip. Just days after the September full moon, a mass coral spawning happens at their study site, a 260-foot arc of reef about 20 minutes by boat from the Smithsonian Tropical Research Institute’s field station in Bocas del Toro, Panama, and each year, since 2000, they have been there to collect data.
Knowlton, a renowned coral reef biologist, has been called Dr. Doom for the grim, but realistic, picture she paints of reefs suffering worldwide. (Her husband Jeremy Jackson, also a prominent marine scientist, is Dr. Gloom.) But she has also been billed as a savior. Vanity Fair, in its May 2007 “Green Issue,” called her a “mind aquatic” that our future, and our lives, may depend on. Along with other marine scientists, Knowlton has been trying to help reefs survive by better understanding coral reproduction.
A close up view of a Montastraea franksi colony spawning (credit: NOAA)
Early in Knowlton’s career, the assumption was that most coral colonies picked up sperm and brooded embryos internally—and some do. But in 1984, Science published the first description of a dramatic mass-spawning event witnessed on Australia’s Great Barrier Reef. Around that time, research biologists were observing the phenomenon in the Caribbean as well. From this, scientists deduced that the majority of corals—called “broadcast spawners”—actually reproduce in this way. Many are hermaphrodites, meaning they release gamete bundles containing both eggs and sperm. But, unable to self-fertilize, they synchronize their spawning with neighboring corals. The more scientists study the annual orgies, the better they have become at predicting when they will happen. The corals appear to use three cues: the full moon and sunset, which they can sense through photoreceptors; and, most likely, a chemical that allows them to smell each other spawning.
Knowlton’s team has been monitoring three closely related coral species—all dominant reef builders in the Caribbean—called the Montastraea annularis complex. What they have found is that M. franksi, one of the species, spawns on average 100 minutes after sunset and M. annularis and M. faveolata, the other two, follow about 100 minutes later, typically five and six days after the September full moon. Over the nine years of the project, the researchers have spotted, flagged, mapped and genetically identified over 400 spawning coral colonies.
As with any long-term study, the scientists’ questions have evolved. At first, they wondered how the three species, spawning at or close to the same time, didn’t hybridize. Their lab tests show that of the three, the early spawner and one of the later spawners are reproductively compatible. But they have found that the hour and a half or so between the species’ peak spawning times is enough time for the gametes to disperse, dilute, age and effectively be rendered unviable. In fact, their data indicates that if corals spawn just 15 minutes out of sync with the majority, their chance at reproductive success is greatly reduced. The looming question now is, what will happen to fertilization rates as coral colonies become few and far between?
By the third of four nights of diving (and no spawning), the suspense was building. The divers playfully suggested playing Barry White as mood music and gorging, pre-dive, on aphrodisiacs like oysters and strawberries.
Around 7:25 PM, just as everyone was slinking into their wetsuits, sea worms called palolo worms began spawning around the boat. The worms break in half and the tail section swims to the surface and releases eggs or sperm in a cloud of bioluminescence.
“This is it,” said Knowlton. “Everybody’s in the mood for sex.”
The water got buggy and electric, and like clockwork, the coral colonies started spawning around 8:20, one triggering another triggering another. The tapioca-like gamete bundles, about two millimeters in diameter and containing about 100 eggs and one million sperm, lifted in unison, slowly drifting to the surface.
The dive team observed 162 different coral colonies set or spawn, and the next night, they saw another 189. Knowlton surfaced that final night, exhilarated. What did you think? She asked each of the divers. Amazing, huh? She didn’t want to get out of the water and grabbed hold of the side of the boat, arching her back, her eyes cast toward the sky. Even the stars looked like gametes.
The mummy of Esankh, male (1070-712 BCE), undergoes CT scanning (credit: Dr. Michael Miyamoto/UC San Diego)
Heart disease may appear to be a recent problem, brought on by the processed foods and sedentary lifestyles of modern living, but it’s been plaguing humanity since ancient times, according to a new study in the Journal of the American Medical Association.
A team of scientists from the United States and Egypt sent 22 mummies from the Egyptian National Museum of Antiquities in Cairo–some of which were more than 3,000 years old–through a CT scanner. They could see cardiovascular tissue in 16 of the mummies. Five definitely had atherosclerosis (calcification in the arteries), and four more probably had it. Heart disease was more common among the mummies of older individuals than those who died before they reached the age of 45. Some mummies had calcification in multiple arteries.
Risk factors for heart disease include tobacco smoking and eating processed foods, but these couldn’t have contributed to the mummies’ atherosclerosis as tobacco and processed foods weren’t found in Egypt at that time. A sedentary lifestyle is another risk factor, but the study’s authors say that even though the mummies were Egyptians of high social status, they were unlikely to have been sedentary. But a further risk factor is diet, and Egyptians of high social status would have eaten meat, including beef, duck and goose.
I guess this is something to consider on my next trip to the burger joint.
Last week, the U.S. government took the brown pelican (Pelecanus occidentalis) off the endangered species list. The birds’ numbers had been depleted first by feather hunters and then by the pesticide DDT. But the pelicans made a comeback, starting with the 1972 ban on DDT, and now there are more than 650,000 in North and Central America. (The birds are doing so well, one even took out a Bugatti Veyron last week, though that may have been due instead to the idiot behind the wheel talking on his cell phone.)
To celebrate the brown pelican’s success, here are eight more species that came back from the brink:
American alligator in a Louisiana swamp (courtesy of flickr user Arthur Chapman)
Alligator leather is not only tough and durable but also pretty attractive. The popularity of alligator hides for leather made hunting of them common in the early 20th century. Even after it was outlawed, poaching continued into the 1970s. But laws that control the movement of hides and the creation of commercial alligator farms have taken pressure off the wild population, which now numbers a million or more.
Like the brown pelican, our national bird nearly got wiped out in the mid-20th century by DDT, which caused female eagles to produce eggs with shells too thin to withstand her weight. With DDT banned in the United States and Canada, the bird has made a full recovery and was taken off the endangered species list in 2007. They remain protected from hunting, though, under the 1940 Bald Eagle Protection Act.
There once were perhaps 20 to 30 million bison (a.k.a. buffalo) roaming the plains of North American. Hunting in the 19th century drove their numbers down to just a few hundred by the 1880s. Only the skins were saved; their carcasses were left to rot. A few small herds survived, though, and the bison population now numbers around 350,000. Most of them, however, are raised on farms for meat. There are only four herds, including the one in Yellowstone National Park, that have not been genetically diluted by interbreeding with cattle.
Their population in Suriname has been dwindling due to habitat destruction and the illegal pet trade. However, captive breeding programs in several zoos have been successful, and scientists plan to reintroduce the frog to areas where they have disappeared.
A male Southern elephant seal (via wikimedia commons)
These large marine mammals, perhaps best know for their large schnoz, were nearly hunted to extinction for their blubber, which was made into oil. Large-scale hunting ended by the end of the 19th-century and the population recovered by the mid-20th, now numbering in the hundreds of thousands.
This 700-pound grouper likes to hang out on coral reefs. But once fishermen discovered how easy it was to spear the fearless fish, the groupers’ population began to dive. Bans on their fishing were put in place in the United States in 1990 and in the Caribbean in 1993. Though still classified as endangered, the goliath grouper’s numbers are rising.
It’s hard to blame people for wanting to kill a predatory creature that goes after your livestock or your pets. But the extirpation of the gray wolf from most of the United States led to unintended consequences for the environment, throwing ecosystems out of balance. A reintroduction program in the Rockies, however, has been largely successful.
Like the elephant seals, humpback whales were nearly wiped out by hunters who wanted their blubber (and also their baleen and flesh). Some 250,000 were killed in the 20th century alone. A ban on hunting, in place since 1966, has let the whale populations recover, and there are now around 80,000 distributed around the world’s oceans.
Science is getting closer to using contact lenses to display information (courtesy of flickr user nikozz)
You’ve seen it in that spy show on TV, or that crazy sci-fi movie you watched last month: The dashing hero places a contact lens over his eye before setting off to infiltrate the bad guy’s secret lair. As he sneaks past guards and cameras, his compatriots are sending him the path to follow, displayed through the tiny lens.
On a more practical note, such technology could be used to display subtitles to help you understand a foreign language, for example, or serve as a display for pilots.
New Scientist reports that these sci-fi lenses are getting closer to real life. A team from the University of Washington has developed a prototype lens that is designed to display information transmitted from a cell phone.
Fitting a contact lens with circuitry is challenging. The polymer cannot withstand the temperatures or chemicals used in large-scale microfabrication, [Babak] Parviz explains. So, some components – the power-harvesting circuitry and the micro light-emitting diode – had to be made separately, encased in a biocompatible material and then placed into crevices carved into the lens.
One obvious problem is powering such a device. The circuitry requires 330 microwatts but doesn’t need a battery. Instead, a loop antenna picks up power beamed from a nearby radio source. The team has tested the lens by fitting it to a rabbit.
Parviz says that future versions will be able to harvest power from a user’s cell phone, perhaps as it beams information to the lens. They will also have more pixels and an array of microlenses to focus the image so that it appears suspended in front of the wearer’s eyes.
There is a willow grows aslant a brook,
That shows his hoar leaves in the glassy stream;
There with fantastic garlands did she come
Of crow-flowers, nettles, daisies, and long purples
That liberal shepherds give a grosser name,
But our cold maids do dead men’s fingers call them:
There, on the pendent boughs her coronet weeds
Clambering to hang, an envious sliver broke;
When down her weedy trophies and herself
Fell in the weeping brook. Her clothes spread wide;
And, mermaid-like, awhile they bore her up:
Which time she chanted snatches of old tunes;
As one incapable of her own distress,
Or like a creature native and indued
Unto that element: but long it could not be
Till that her garments, heavy with their drink,
Pull’d the poor wretch from her melodious lay
To muddy death.
–Hamlet, Queen Gertrude, Act IV, Scene VII
Thus ends Ophelia’s tale in Shakespeare’s play, with her body floating in a muddy pond. Sir John Everett Millais painted her thus; his Ophelia hangs in the Tate Britain in London. Reproducing such a masterpiece would be difficult, but how about doing so using bacteria as your medium? Artist JoWOnder did that and photographed the result as it changed over six days; all six versions can all be seen in the Microbial Art gallery online:
Artist JoWOnder presents a pre-Raphaelite painting of Ophelia created with bacteria. The demise of the painting is filmed using time-lapse photography, showing a story of death and creation of new life. The colors and animation for ‘6 Days Goodbye Poems Of Ophelia’ were created in a laboratory at Surrey University UK with the help of microbiologist Dr. Simon Park. When displayed in 2010, this will be an outdoor video installation of Ophelia with poems submitted from the public. Composer Milton Mermikides will be producing a sound track based on the genetic code of bacteria that colonize the gut. The video below includes poems for Ophelia collected through voicemail.
Amazon rainforest deforestation, courtesy of Flickr user Threat_to_Democracy
Here’s a roundup of the best of what I’ve been reading in the past couple of weeks:
Are global warming and deforestation too scary for Sesame Street?: A couple of years ago Sesame Workshop named these as adult topics too scary for young children. Instead they focus on teaching kids to respect the Earth. Climate change and deforestation are scary, and I’m okay with keeping them away from five-year-olds. Am I wrong?
One Giant Leap seen again: Bad Astronomer Phil Plait has images from the Lunar Reconnaissance Orbiter of the Apollo 11 landing site. You can even see the lunar lander footpads.
Pigs Prove to Be Smart, if Not Vain: Pigs successfully pass the mirror self-recognition test, a sign of cognition. But if pigs are smarter than we think, will we still eat them? (No bacon would be a bad thing.)
And though I had been looking forward to reading Superfreakonomics (having been a fan of Freakonomics), I’ve decided to skip it. I’ve now read several essays critical of their climate change chapter, but it’s the open letter on Real Climate from geophysicist Raymond T. Pierrehumbert that has convinced me that the Freakonomics team desperately needs a fact checker. I’d offer my services, but Smithsonian keeps me pretty busy.
Discover magazine has announced the winners of their Evolution in Two Minutes or Less contest. The video above, by Stephen Anderson of Texas, won the viewer’s choice. Other videos, including the official winning video and an explanation from judge PZ Meyers, can be found on the contest web site. Which was your favorite?
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