Mauka to Makai
A science blog for the massesArchive for November, 2008
Pine Beetle Drama
What’s red and dry and dead all over? Pine forests throughout western North America, that’s what. (If you said itchy, flaky skin, you’d be wrong… and kinda gross.) The western slopes of the Rockies are undergoing what’s been called the largest landscape change since the Ice Age. And it’s all thanks to a little beetle that’s no larger than your pinky fingernail.
The Mountain Pine Beetle (or MPB) is a small black beetle that looks, well, like a beetle. MPBs swarm pine trees, and bore into the bark to lay eggs–each female lays 60 to 75 eggs. Not only do MPB larvae munch their way through the important bits of the tree trunk (the xylem and phloem cells responsible for water and nutrient transport) but they also introduce a blue fungus that knocks out whatever xylem and phloem tissue the larvae miss. With no way to shuttle water and nutrients from one part of the tree to another, the pine tree becomes red, dry and dies within a year. The death of one tree is no big deal, but millions and millions of acres worth of dead trees…That’s a slightly bigger problem. Scientists estimate that 90% of British Columbian pine forests will be red, dry and dead in just eight years.
Stories of seemingly insignificant animals bringing entire ecosystems to their knees are pretty common these days. Zebra mussels are modifying the Great Lakes. Cane toads are transforming the Australian outback. Zebra mussels and cane toads are invasive species–animals introduced into an ecosystem where they don’t belong. But our little western agent of change, the MPB, is a local. In fact, it’s been on this continent longer than humans have.
Hmmm…If MPBs have been here all along, why the sudden drama? The answer: Smokey the Bear’s done too good of a job limiting forest fires–oh, and climate change is to blame, too.
Beetles primarily attack mature pine trees (FYI: Lodgepole pines are mature at 80 years), but they can also take out weakened or unhealthy stands of pine. Before Smokey started enlisting you “to help prevent forest fires,” periodic fires kept the forest thin and the concentration of mature trees low. Our forest fire fighting efforts have kept this natural process at bay, setting the table for an MPB buffet.
And then there’s the whole climate change thing.
After hatching, the larvae spend the next ten months overwintering in the tree trunk. Apart from predators like parasitic wasps and woodpeckers, the biggest threat to MPB larvae is a cold snap. When winter temps fall below -35°C (-31°F) for several days in a row, the bitter cold kills off most of the larvae in the tree trunks. Sans cold snap, however, the larvae keep chowing on the dying tree until they pupate and emerge in early summer as the next generation of MPB ready to fly off and find a new tree to kill. As more larvae survive the warmer winters, the MPB population grows with each successive generation-as does the population’s tree-killing potential.
Thanks to higher numbers (and warmer winters) MPBs are crossing the Rockies–a geographic boundary that used to quarantine the little buggers in the west. And, if it keeps getting warmer, the northern Boreal Forest that stretches from Alaska to northern Québec could be the beetles’ next dinner destination.
That would be bad. It would be bad because we don’t want to lose the Boreal Forest to an infestation of voracious beetles-obviously. But that’s just the tip of the badness. You see, in a “normal” situation, MPBs curb their own population by eating themselves out of house and home. (They eat all of the mature trees, then move onto the smaller trees, but the small trees die quickly and leave the larvae homeless. Homeless larvae can’t survive the winter and thus endeth the MPB outbreak.) There are a lot of trees in the Boreal Forest-enough mature trees to keep the MPBs happily munching for a long, long time. They could munch their way east and then they could munch their way south-and then west and north and east and south. And that would be bad.
Yummy!
Fish mucus! Yum! At least that’s what bluestreak cleaner wrasses think. Bluestreak cleaner wrasses are fish that clean other fish. They’re not supposed to eat the tasty mucus that protects their clients from disease, stinging cells and UV rays. They’re supposed to eat the parasites attached to their client’s skin, but sometimes they can’t resist sneaking a nibble of that scrumptious mucus. (And biting a client definitely ranks as one of the dumbest business decisions a little fish could make.) The client, who signed up for something more like a bath than some sort of kinky biting thing, quickly shakes the cleaner off and high tails it outta the cleaning station. And so the client stays dirty and the cleaner stays hungry (despite that bite of delectable mucus).
That’s not how cleaning is supposed to work. It’s supposed to be a simple, mutually- beneficial relationship—big fish pull into a cleaning station where tiny cleaners (like wrasses, gobies and cleaner shrimp) clean them and get a free meal as they eat the client’s dead skin and parasites.
So how’s a cleaner fish with a biting problem gonna find work (and food)? With a little help from a friend, according to scientists from Stockholm University. They found that pairs consisting of one male and one female bluestreak cleaner wrasse provide a much better cleaning service (with much less biting) than a single wrasse. Also, when the wrasses team up, the male seems to be in charge of quality control, chasing the female if she tries to sneak a bite of mucus.
Cleaning stations are so much more than undersea carwashes. They also serve as safe havens for snack-size fish. When predators pull into a cleaning station, the tiny (totally munchable) cleaner fish provide a little extra pampering. As they clean the big fish, they gently caress it with their fins. This massage seems to put the big bad predator in such a state of relaxation that it loses its appetite, keeping the cleaner fish safe—and making the cleaning station an ideal hangout for itty-bitty fish.
What do these cleaner fish have to do with you? Nothing, absolutely nothing, but we can’t talk about fish and pampering without mentioning the garra rufa—the pedicure fish. Garra rufas aren’t exactly cleaner fish. They’re just hungry fish.
Garra rufas, also called the “Doctor Fish of Kangal,” naturally occur in a hot spring near Kangal, Turkey. The waters of the hot spring are too warm to sustain much of anything edible so the toothless fish gobble up whatever they can find—anything from dead human flesh to other garra rufas. That’s right, these fish feast on scabs, blisters and other skin “imperfections,” but locals didn’t notice the healing abilities until the early 1900s when a shepherd’s wounded leg healed after he bathed in the hot spring.
Stories of the healing powers of the fish and the spring grew and in the 1950s the locals built a wall to preserve a captive school in the hot spring. Soon, a resort opened, and today, more than 3,000 people visit the spring each year to allow the Doctor Fish and the high selenium waters of the hot spring to cure their skin ailments.
Now, thanks to globalization and a few gutsy spa owners, you don’t have to go to Turkey to get the garra rufa treatment. A few salons in the United States are now offering fish pedicures where clients dunk their feet in tanks of warm water and let dozens of garra rufas nibble away at their calluses. Some people (including the health departments in Texas and Washington) think it’s gross. Others find it as decadent as a cleaner fish fin massage.
Mooching: it’s natural
Biomimicry is the new frontier. Scientists and engineers are looting Mother Nature’s treasure chest of unpatented intellectual property all over the world–from termite mounds in Zimbabwe to purple bacteria in Arizona. And it’s doing the planet a whole lot of good.
What is biomimicry, you ask? Webster’s defines it (rather laboriously) as “the copying or imitation of a natural phenomenon’s or environment’s efficiency and survival mechanisms in manufacturing processes.” In short, it’s when we mooch good ideas from nature.
Take the Zimbabwean termites (or any African termite for that matter) as an example. They dig a complicated series of ventilation tunnels that draw in cold or hot air, circulate it through the termite mound and then expel the air through chimney vents. While the outside temperature varies by as much as 40ºC (that’s a change of 72ºF), the termites keep the internal temperature of the mound steady by plugging vents or digging new ones.
The architect of a shopping mall in Harare, Zimbabwe, used termite know-how when he designed the building’s ventilation system. (Fans and modern ductwork replace the need to have thousands of termites constantly blocking and unblocking air tunnels.) The design requires 90% less energy than a standard system for a building of the same size.
But biomimicry goes far beyond the wonders of ventilation engineering (as fascinating as that may be). For instance, the “sharkskin” racing suits that caused such a kerfuffle at the Beijing Olympics are really just a rip-off of actual sharkskin. Speedo scientists noticed that shark scales allowed water to flow smoothly over sharkskin, limiting turbulence and the amount of slippage in the water. This allowed the scales to essentially grip the water. Certain they were onto something truly magnificent, Speedo engineers–yep, there are engineers behind those banana slings–recreated the shark scale design in super-stretchy material. Turns out, they were right. When super-fit Olympic swimmers hit the water in the fast suits, they flew–and records shattered. (Note: the suits are genius, not magical…you still need to train.)
Biomimicry inspiration doesn’t just come from awesomely powerful animals like sharks… and er… termites. For instance, back in 1948 a Swiss engineer by the name of George de Mestral picked a cocklebur off his pants and looked at it under a microscope. Voila! The idea for Velcro was born. Mestral noted that the burr clung to his pants because it had hundreds of tiny hooks on its exterior. He used nylon to reproduce those hooks on one piece of fabric and a series of nylon loops on another piece of fabric to invent a new fastener (much to the joy of kids-and grandparents-the world over).
Solutions to our problems are all over the place in nature. Here’s another example: The bumps on humpback whale fins (called tubercules) allow water to flow smoothly over the fins. This allows the 60-ton behemoth to be as graceful as a ballerina. When engineers stole this tubercule concept to improve the design of wind turbine blades and airplane wings, they improved the efficiency of the blades and wings by 32%.
So how does Nature think up so many cool things? Darwin. Well, more appropriately, evolution and the whole “survival of the fittest” thing. Organisms struggling to survive in the wild have to come up with solutions to life’s many challenges. Over time (3.8 billion years of trial and error) a lot of animals have learned how to live in different environments and have picked up some pretty funky tricks along the way.
The tricks that are so essential to survival in the wild can be used by humans trying to find simple and environmentally-friendly solutions to life’s little problems. The proteins that oysters use to control how and when their calcium carbonate shells grow can be used to reduce the buildup of calcium carbonate on the inside of water pipes. And purple bacteria that use the sun’s energy to generate massive amounts of hydrogen use a fraction of the energy required to produce hydrogen by electrolysis (the way we currently generate hydrogen, NOT–for those of you wondering–the way we remove unwanted hair). Scientists are trying to figure out exactly how to mimic the bacteria to harness solar power.
So there you have it: The plants, animals and bacteria that have managed to survive and thrive on this planet for the last 3.8 billion years are the real innovators. We’re just mooches.
Do whales have ears?
It’s a pretty crappy time to be a cetacean—killer whales are hungry, beluga whales are contaminated, right whales are getting smacked by ships, bottlenose dolphins are getting caught in fishing gear and then of course, minke, sperm, sei and brydes whales are being hunted under Japan’s scientific whaling program.
As if that wasn’t bad enough, scientists have now discovered something else that might make life a little harder for whales and dolphins. The ocean is getting noisier, thanks to an old friend. (Nope, not the Navy.) It turns out that carbon dioxide, that ubiquitous greenhouse gas, is pumping up the volume in our oceans. Confused by the connection? So are scientists, but they know this much:
Oceans absorb carbon dioxide. They always have. But because we’re pumping more carbon dioxide into the atmosphere now than ever before, more CO2 is landing in the ocean as well. When CO2 mixes with seawater it forms carbonic acid (the stuff that makes fizzy drinks fizz) and as the amount of carbonic acid in the ocean increases, the ocean becomes more acidic. (For more on ocean acidification see The Ocean’s Big pHat Problem.)
Sound travels farther in more acidic seawater because—for some reason—seawater absorbs less sound as it becomes more acidic. Right now, researchers say that underwater sound is probably traveling 10% farther than it did 100 years ago, but they predict that sounds could travel up to 70% farther in some parts of the ocean by 2050.
And what does that have to do with whales and dolphins?
Sound travels way faster underwater than in air. And so marine mammals depend on sound for pretty much everything. They use sound to communicate locally and over long distances—humpback songs can be heard 100 miles away and blue whale sounds can reach more than 1,000 miles. Some cetaceans also use sound to identify objects (like prey and icebergs) through a process called echolocation. But being so sound-centric isn’t all it’s cracked up to be.
Por que? Because the ocean is noisy and some of the noises—those from military sonar—are so loud and scary that the whales want only one thing: to get the hell outta dodge. For the whales, that means stranding. And that’s what they do. Since 1989, at least 10 mass stranding events have been linked to military sonar use. Some of the stranded animals have shown signs of physical trauma, including signs of “the bends”—the illness that can kill scuba divers who surface too quickly.
Sonar isn’t the only noise in the ocean. Ship engines make noise, as do blasts from seismic exploration. There are plenty of natural sounds too, like earthquakes, noisy parrotfish chomping on coral and of course, the whistles, clicks and melodies of whales and dolphins.
As sound travels farther and farther underwater, the ocean will become even noisier. Whales may be able to communicate with one another over longer distances, but the level of background noise will increase. What once sounded like a quiet bistro will come to resemble Chuck E. Cheese’s. How will this affect the whales? Will they be able to accurately assess their environment through the chaos? Will the sounds of sonar threaten whales hundreds of miles away?
So many questions, but one still lingers: umm, do whales have ears? Yes, but they don’t have external ears—that would be completely impractical for any deep diving animal—instead, they hear through their lower jaw bone. That’s right, the lower jaw acts like an antenna. Sound travels along a fat channel within the jawbone directly to the inner ear.
