Our World — 3 January 2009
MUSIC: "Our World" theme
This week on a special edition of "Our World," some of our favorite stories of 2008 ... including a look at the threats facing the bees that pollinate our food ... a visit to California's majestic, hundred-meter tall redwood trees ... and just under foot, the secret world of soil ...
MEGONIGAL: "Consider climate change, and because soils hold twice as much carbon as the atmosphere does, they regulate climate. One might say, in fact, that we drink, eat, and breathe soils."
Mmm. Those stories and more, including a conversation about how ants and trees in East Africa have a kind of mutual aid society.
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
California's majestic redwoods and their unique ecosystem
We start this week with a story we ran around Earth Day. VOA's Adam Phillips brought us along to Northern California and some of the most magnificent natural beauty on Earth.
PHILLIPS: It is midday in California's Año Nuevo State Park, home to one of the last original stands of old-growth redwood trees left in the West. These giants can stand ramrod straight nearly 120 meters high before their branches of needled leaves form the crowns, mostly obscuring the sun.
After one's eyes adjust to the dim golden-green light, the first thing one notices is the hush.
STRACHEN: "These trees are very unique. Any human being that walks amongst them and sits for a while, all of a sudden realizes how magnificent this forest is."
PHILLIPS: Gary Strachen has been a park ranger here for more than three decades.
STRACHEN: "I can't get too existentialist, but they do give off a spirit, and they inspire. And I think humans now have realized, worldwide, that it's important to keep and protect ancient forests like this."
PHILLIPS: These ancient forests are found only in the areas of California near the ocean, explains Portia Halbert, an environmental scientist for the state.
HALBERT: "They are limited to this area of California where there is 'fog drip.' When fog comes in from the ocean, the fog collects on the little needles of the tree and then it drops around the tree roots. We have rain about six-seven months out of the year and then it's completely dry the rest of the year. And so this fog drip allows the trees to live through a very long dry period."
PHILLIPS: Unlike most trees, which have deep roots to reach underground water, Halbert explains that redwoods rely on the moisture that pools on the forest floor.
HALBERT: "These trees have all of their roots within about one meter of the ground. All of the trees are growing together. Their roots are connected and they keep each other upright, and you'll have trees that are more likely to fall down when adjacent trees fall down because they've lost that support of their neighbors."
PHILLIPS: When those trees do fall, they tend to stay where they are and to decompose very slowly. That's because insects, which normally eat and break down fallen trees, don't like tannin, the chemical that gives redwood bark its deep russet color.
But all woodlands need some way to clear out dead wood and other debris. Halbert says that redwood ecosystems rely on the lightning fires, which naturally occur every 50-75 years. The blazes begin above ground, often travel down to the shared root systems beneath the groves, then upward inside the trunks.
HALBERT: "And the fire will burn and burn and burn like an oven inside the tree. And so sometimes the fire will burn so long and so hot that it will hollow out the entire middle portion of a tree. You can stand inside a redwood tree and look up and see the sky. But the tree is totally alive because its living tissue isn't damaged. The bark is protected on the outside and the inner tissue is protected on the inside."
PHILLIPS: Today, there are birds in the skies above the trees, such as the giant pileated woodpecker and the marbled murrelet, a web-footed seabird that spends most of its time far offshore in the Pacific Ocean. It was once a great mystery where this bird nested. But in 1974, scientists learned that it actually flies up to 80 kilometers inland to lay its eggs in the tops of old growth trees like these.
STRACHEN: "If you are sitting in here at dusk or early in the morning, it will be all quiet and all of a sudden you will hear this [whistle] coming through the canopy, you know. And you'd see this black streak. It looks like a stealth jet. And it'd be flying so fast right through the canopy. And that is the marbled murrelet."
PHILLIPS: Vigorous efforts in California to preserve habitats like this have allowed this ancient bird to continue to thrive in the Golden State.
STRACHEN: "And I am a firm believer that every leader should be made to - mandatory! - sit in an ancient forest and just sit there and think. It is a place where you think can clearly."
PHILLIPS: … thinking, perhaps, about the value of protecting old growth forests like this. In a redwood grove in California's Año Nuevo State Park this is Adam Phillips reporting.
Bee colony deaths continue to baffle researchers
Honey bees are essential for the pollination of many food crops. But more and more bees are dying each year. Parasites, viruses, and pesticides may all play a role, but as Véronique LaCapra reports, in a story we first aired in June, researchers are still baffled by what they call colony collapse disorder.
LaCAPRA: Honey bees are the most valuable pollinators of agricultural crops worldwide. In the United States, approximately 130 crops depend on honey bees for pollination. Their work is worth about $15 billion a year.
VANENGLESDORP: "We estimate that one in every three bites of food we eat are directly or indirectly pollinated by honeybees."
LaCAPRA: Dennis VanEnglesdorp is Pennsylvania's acting state apiarist. He's responsible for tracking the health of the state's commercial honey bee colonies.
VANENGLESDORP: "Honeybees are the movable pollination force in modern agriculture."
LaCAPRA: Almonds, blueberries, and apples; carrots, onions, and squash - all of these fruits and vegetables grow in different parts of the country and bloom at different times of the year. So, to meet the pollination demand, commercial beekeepers truck their hives around the country. A single beekeeper may move tens of millions of bees, covering thousands of kilometers in a single trip.
VANENGLESDORP: "So all your fruits and vegetables, all your flowering plants require insect pollination, and honey bees do a majority of that pollination."
LaCAPRA: In the 1940s and '50s, there were approximately five million managed bee colonies in the United States. Today, that number has dropped to less than half that. Severe declines began in the 1980s, with the accidental introduction of a new parasite called the varroa mite.
VANENGLESDORP: "It has these very sharp mouthparts that pierce the skin or exoskeleton of the bee. And actually it spits inside the bee, and in that spit we believe that there's a protein which acts a lot like AIDS virus does in the fact that it breaks down the insect's immune system. This is our biggest challenge, and it still kills most of the colonies in the country."
[ Sound of bees ]
PETTIS: "And what you want to do, the way you're going to get stung - no, I'm just going to tell you so that you'll - no, no, I'm just saying, the way you would get stung, is as you grab this frame…"
LaCAPRA: Jeff Pettis is the lead scientist at the U.S. Department of Agriculture's Bee Research Lab, just outside of Washington, D.C.
PETTIS: "So, just pick it up ... and you're a beekeeper."
LaCAPRA: Pettis and his team have been studying a more recent and mysterious threat to honey bee colonies.
PETTIS: "We're suffering probably 15-20 percent losses normally throughout the year of honeybee colonies. Our last two years we've been over 30 percent losses, and so this is what we're calling this phenomenon of CCD, colony collapse disorder."
LaCAPRA: CCD looks very different from other causes of bee death, and it happens much more quickly: within just a few weeks, most of the adult worker bees disappear from the hive, leaving the queen and all the young bees behind.
Since CCD was first reported, researchers have been scrambling to find a cause.
PETTIS: "We've done enough looking and testing and sampling of the bees that are there, that if we had one single novel pathogen or problem, that we would already have identified it. We think it's a complex, maybe even a syndrome - things that are coming together to cause the losses of bees."
LaCAPRA: The lack of clear answers worries Dennis VanEnglesdorp.
VANENGLESDORP: "These large migratory [beekeeping] operations, which we rely on to move across the country in order to pollinate these different crops, are in real danger, because they can lose 30, 50, sometimes 80 percent of their colonies. They can absorb a loss like that one year in a row, maybe two years in a row, but they can't do it three years in a row and stay in business."
LaCAPRA: And bee declines are not limited to the United States.
VANENGLESDORP: "We are hearing reports from Europe, from Canada, and from South America, even some from Asia, where honeybee populations are collapsing and decreasing."
LaCAPRA: There are still enough bees in the U.S. to meet demand. But VanEnglesdorp warns that continued colony losses could threaten the production of some crops, and drive more and more beekeepers out of business. For Our World, I'm Véronique LaCapra.
Top choices from 2008's Websites of the Week
A regular feature here on Our World is the Website of the Week, in which we showcase interesting and innovative online destinations.
We don't have time to review all the ones we featured in 2008, but I did want to highlight a few of them.
The American Society of Civil Engineers website features a worldwide honor roll of great construction, from the Panama Canal to the Victoria Falls Bridge, plus the ten civil engineering achievements considered to have had the greatest positive impact on life in the 20th century. Duke University engineering professor Henry Petroski helped make the selections.
PETROSKI: "Over a century there was a great deal of advance in technology, but that wasn't for technology's sake. It was really to make life more comfortable, to give people more freedom of movement. Something like the Interstate Highway System in the United States made it very, very convenient for people to go from place to place."
More civil engineering landmarks at asce.org/history
Engineers and scientists tend to speak a bit more formally than, say, teenagers. So if you want to keep up with the latest English words and phrases that you won't find in regular dictionaries, you might want to thumb - well, virtually thumb - through the Urban Dictionary.
PECKHAM: "Urban Dictionary is a slang dictionary with definitions written by people who come to visit the site. So all of its content is written by normal people like you and me."
Aaron Peckham is the founder of UrbanDictionary.com, which is fun, engaging, and up-to-date, if not exactly scholarly. It is, we should warn you, full of words you can't say on the radio. But of course, those might just be the words you need to know about.
And if you've been enjoying all those free web sites, here's a way to give back. WorldCommunityGrid.org uses the power of millions of computers to help solve complex scientific problems.
LITOW: "The power on World Community Grid is used purely for humanitarian purposes - cancer research, research on dengue fever, rice DNA - all kinds of public purposes. So that's one thing. But the second thing is, it's a permanent source that can serve humanitarian needs year in and year out."
Stan Litow explained that grid computing breaks those big problems into little pieces and sends them out to computers like yours. While your computer isn't busy doing your work it can help scientists solve big, important problems. It's like having a tiny bit of a supercomputer right on your desk.
Those are just a few examples to highlight the diversity of the web. We have links to these and more than 230 other featured Websites of the Week on our website, which is voanews.com/ourworld.
MUSIC: Don Harriss - "Inventions"
And you're listening to VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.
Museum exhibit highlights secrets of soil
Scientists say we know less about the soil under our feet than we know about the dark side of the moon. To raise public awareness about the importance of soil, the Smithsonian Institution opened an exhibit called "Dig It! The Secrets of Soil" in July, which is when we sent Eric Libby to scoop up some dirt on this earthy topic.
LIBBY: Beneath our feet is a living, breathing, pulsating world. Worms, plants, bacteria and fungi thrive in the dynamic environment of soil. Dig It curator Patrick Megonigal says there are more microorganisms in just a handful of soil than there are human beings on earth, and yet we know about only about one percent of them.
A major goal of the exhibition is to show visitors the importance of soil. While most people know that crops depend on good soil, Megonigal stresses other ways soil affects our lives.
MEGONIGAL: "Consider the importance of water quality and the fact that every drop of freshwater passes through soils on its way to aquifers and reservoirs. Consider climate change and because soils hold twice as much carbon as the atmosphere does, they regulate climate. One might say, in fact, that we drink, eat, and breathe soils."
LIBBY: Dig It makes that point with vivid photographs and videos and interactive displays. Take the entrance hall, for example, which shows visitors what's happening under an oak tree. Round screens along the wall show videos of ants and worms busy at work. From here, the visitors step into a large room with samples of soil from each of America's 50 states. The soil colors range from orange to red and brown to black, depending on their mineral ingredients.
A different approach to soil composition is on display above what looks like a kitchen stove, where a video screen shows an animated cooking show. It's based on the real television program Iron Chef, in which chefs compete to make the best meal with a secret ingredient. In this exhibit, the aptly named chefs Pierre LeTerre and Sandy Marsh try to make the best soil.
SOIL CHEF ANNOUNCER: "And now we are ready to reveal today's secret ingredient - sand! Chefs, you have just 6,000 years to create a unique soil from sand. A quick word about this ingredient. It's mostly sand but also has minerals rich in iron that give it that distinctive color...."
LIBBY: Visitors learn that two very different soils can develop from sand, depending on environmental conditions.
The engaging explanations continue in the next room, where visitors can step into the Matters of Life and Death theater to watch the short feature, Soil Science Investigators. In this case, the investigators use their knowledge of soil composition, food decay, and plant growth to discover who murdered Linus IV - a pumpkin.
MAN: "About 42 inches [one meter], victim is at least a 100 pounder [45 kilos], I'm guessing. Loamy soil, a lot of aeration, and reliable water. Smart grower. Whatcha got, Olivia?"
OLIVIA: "Pulpy liquid. The lab will tell us how long it's been here."
MAN: "Soil, it's the greatest - tells us how things grow and how things die!"
LIBBY: Other rooms show how soil plays a role in filtering drinking water and affecting climate change. Other displays discuss the twelve types of soil found in the world. A giant map uses colors to show the distribution of these soils, explaining why some countries can grow crops that neighboring countries cannot.
When finished exploring the Dig It exhibition, visitors will leave knowing that what they scrape off their shoes is more than just dirt. This is Eric Libby in Washington.
Ants, trees and plant-eating animals help each other
And finally, an intriguing story about mutualism - that's what biologists call it when different species have a mutually beneficial relationship.
For example, our intestines are packed with bacteria that help us digest our food. In exchange, we provide them a place to live and something to eat.
Back in January we talked with University of Florida researcher Todd Palmer, who described a fascinating mutual relationship between ants and acacia trees that he has been studying in Kenya.
PALMER: "The classic work that was done on mutualism was by a guy named Dan Janzen at the University of Pennsylvania. And he studied an acacia species in Central America and its ant associates, and was the first scientist to demonstrate that the ants were, in fact, protecting the tree from encroaching vegetation and also protecting the trees from herbivores. And in exchange, the plants were providing housing and food for the ants."
Q: In your paper you took advantage of something called the Kenya Long Term Exclosure Experiment, not enclosure but exclosure. Was that originally designed to do the sort of study that you did, or was that set up for some completely different reason?
PALMER: "One of the things that ecologists do a lot of is throw up fences. You know, build fences, keep things out of areas and see what happens to the communities inside."
Q: Did you set out to look at the influence of the exclusion of the herbivores, or did you simply notice- How did the idea generate here?
PALMER: "It stemmed from one of the most obvious things that I had managed to miss on a daily basis for about eight years. (laughs) I was walking down the road next to the exclosures one morning, and I suddenly realized that the trees where the herbivores were present looked healthy and vigorous. And when I looked to my right, to the trees on the inside of the electrified fences, they looked like they were in very bad condition. And that struck me as a little paradoxical because my intuition was that if you remove herbivores, if you remove something that feeds on a tree, you'd expect the tree to start to flourish and do well, and what I was seeing was sort of the exact opposite of that."
Q: So, what's the mechanism here? How are the ants and these acacia trees benefiting each other?
PALMER: "Essentially what the trees are doing is producing these bulbous swellings, which are called domatia, and they're essentially ant housing. In addition, the trees produce a sugary solution and the ants forage on that nectar and use that as one of their sources of carbohydrates. In exchange, the ants, in an ideal world, are supposed to be protecting the tree from herbivores. And when you disturb the tree, they essentially come running out and swarm onto the offending creature and basically they aim for the mucous membranes, so they go for the eyes, they go for the insides of the nose, (laughs) various things like that, as well as the lips and inside of the mouth. And so what that does is essentially reduce the duration of the feeding bouts by these herbivores that are so fond of eating these trees' leaves and branches."
Q: Since the ants are there to protect the trees from the herbivores, it seems, one would think, that if you fence out the herbivores, then the trees should thrive, but they don't. Why is that?
PALMER: "That's an excellent question, and essentially what seems to be happening is that the trees over a period of somewhere between five and ten years start to realize that the herbivores are no longer around, and so what they do is they start reducing their investment or their payment to these ant-bodyguards, so they start producing fewer of these bulbous homes and they start producing fewer of these active nectaries that secrete the sugar-like solution as a way of sanctioning the ants because they no longer have as great a need for the ants' services."
Q: Is there a larger message in this paper in particular and this sort of research in general?
PALMER: "Yeah, I would say the cautionary tale is that while mutualisms are very, very slowly done, they can be very rapidly undone. And in the face of global climate change and, you know, all the kind of human-induced alterations of the world's landscapes, we don't really have a good sense of what those large scale manipulations are going to be doing. It's basically a big, unintended experiment, the consequences of which could be not so good for us, especially because as humans, we rely pretty heavily on a lot of different mutualisms from pollination of agricultural crops to fisheries that rely heavily on coral reefs as sites for young fish to develop. So the potential for collapses in these mutualistic relationships as we change the environment is great, and the speed with which those relationships can collapse sort of makes your head spin."
We reached Todd Palmer at the Mpala Research Center in Kenya. His paper on ants, acacia trees, and plant-eating animals was published in the journal Science.
MUSIC: "Our World" theme
That's our show for this week. If you'd like to get in touch, email us at ourworld@voanews.com. Or use the postal address -
Our World
Voice of America
Washington, DC 20237 USA
Rob Sivak edited the show. Bob Doughty is the technical director.
And this is Art Chimes, inviting you to join us online at voanews.com/ourworld or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.