Mauka to Makai

A science blog for the masses

Archive for March, 2009

Water

March 27, 2009 at 12:43 am · Filed under climate change, clusterf**kery, innovation and tagged: , , , ,

It’s a big week for “holidays.” Last Saturday, March 22 was World Water Day, Monday was National Puppy Day, Tuesday marked the 20th anniversary of the Exxon Valdez oil spill, today (March 26) is National Nougat Day, and Earth Hour is this Saturday, March 28, from 8:30-9:30 pm.

We could spend hours discussing the essence of nougat, but let’s back up to World Water Day (a day to celebrate—and advocate for—the sustainable management of freshwater). Today, about a third of the global population doesn’t have a dependable source of clean water. According to the UNEP, 1.8 billion people will live in countries with “absolute water scarcity” by 2025.

WTF?

The Earth has approximately 1.4 billion cubic kilometers of water (326 quintillion gallons), but 97% of that water is the salty stuff in the oceans. That leaves about 35 million cubic kilometers of freshwater, but most of that is locked in glaciers or deep underground aquifers, out of human reach. Of the stuff we can reach, a lot of it is too dirty to use or it’s MIA thanks to drought or over-consumption.

Over-consumption is a result of over-population—the more people on the planet, the more water we need for agriculture (70% of water use), industry (20%) and just regular ol’ domestic use (10%). Right now, we’re tapping India’s Ganges and Indus Rivers, the Nile (in Egypt) and the Yellow River (in China) so heavily that they no longer flow to the sea (except in rare wet years). Similarly, the mighty Colorado River—carver of the Grand Canyon—often runs dry by the time it reaches the Bay of California due to agricultural demands for water in the southwest.

The Colorado River isn’t the only source of agricultural water in the United States. The Ogallala aquifer—the largest aquifer in North America and one of the biggest in the world—provides 30% of the ground water used for irrigation in the US. But the amount of water in the Ogallala is shrinking. Every year, we pull 12 cubic kilometers of water out of this aquifer. Overall, we have pulled a volume of water equal to the annual flow of 18 Colorado Rivers out of the Ogallala. Some scientists estimate that it will be dry in 25 years.

On top of everything else, climate change has to make everything a little bit worse by making the dry places (like Australia and the Sahel region of Africa) even dryer. Whether a result of global warming, natural cycles or a combination of both, mega-droughts are happening in areas where human demand for water has pushed the local systems to the breaking point.

Don’t fret! We can MAKE rain. Maybe. Using a questionably brilliant, questionably effective and just plain questionable process known as “cloud seeding,” some people swear they can make it rain. The Chinese government is a big proponent of cloud seeding, firing silver iodide rockets into the sky when they want rain. Or snow. In February, China closed 12 major highways around Beijing because of heavy chemically-induced snow. Oops.

Not everyone is jumping on the “rain enhancement” bandwagon (for obvious reasons). Instead of trying to make rain to make water, people are trying to MAKE water. This is where Dean Kamen (the inventor of the Segway) comes in. He has invented a machine that can turn anything—puddle water, ocean water, urine—into clean freshwater. The machine, called “the slingshot,” can produce 1,000 gallons of clean water per day using an incredibly efficient process of vapor compression distillation. The slingshot can be powered by electricity or a Kamen-designed generator that runs on anything that burns (like propane—or poop). Of course, with a current price tag of $100,000, the slingshot isn’t quite ready for mass marketing.

There you have it. World Water Day: a rather depressing holiday. Now, get back to celebrating nougats and puppies.

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Baby-Making

March 17, 2009 at 6:51 pm · Filed under wildlife and tagged: , , , , , ,

Scoring a mate is only the first step in successful reproduction. The real challenge—and the whole point of mating, biologically-speaking—is successfully passing one’s genes on to the next generation (in other words: making babies).

To ensure some sort of reproductive success, most animals mate with as many individuals of the opposite sex as possible. For other animals, successful baby-making is a whole lot more complicated…

Some animals depend a little too much on a good pick-up line:

According to the IUCN, there are only 7,500 cheetahs left in Africa—plus 60 or so in Iran—and scientists doubt that even half of these animals are capable of reproducing successfully (thanks, in part, to some serious inbreeding). For cheetahs that are reproductively competent, baby-making is still a challenge.  

Unlike other cats, female cheetahs don’t have regular estrus cycles and they rarely ovulate. Without an egg raring to go, an impromptu roll in the grass will not result in any cute little cheetah cubs. Instead, as scientists recently learned, cheetah pregnancies must be planned. And it’s the male that calls the shots, literally.

Male cheetahs produce a sound called a “stutter bark” that has an aphrodisiac-like effect on the ladies. Males stutter bark for a few days at a time, a few times a year, max. The stutter barking starts out at a fairly mellow pace on the first day and increases with intensity as the days progress. The female cheetah, who spends most of her life on her own, eventually responds to the male’s wooing by flicking her tail, rolling around in the grass and ovulating.

…Some take the phrase “no pain no gain” to a whole new level:

Sex isn’t exactly “fun” for female seed beetles, yet they mate five to ten times during their 25-30 day lifespan. Male seed beetles’ genitalia are armed with barbs and spikes that (obviously) injure their female partners. Scientists recently discovered that males with the most brutal sexual organs successfully fertilized more eggs than those with relatively wimpy genitalia. Why? Scientists don’t know for sure, but they think the longer spines may serve as a more effective anchor inside the female.    

In a recent unrelated study, scientists asked a crucial question: why, why, WHY do female seed beetles mate more than once? The answer: for water. It is not clear whether female seed beetles want the water because they’re thirsty—they typically inhabit arid habitats—or because they need the water to store more sperm and therefore increase their reproductive success.

…And for some animals, successfully passing their genes on to the next generation is absolutely positively THE most important thing in the world: 

The baby-making odds are stacked against male Australian redback spiders. They only live eight weeks and only 20 percent of them will actually find a female companion during their lifetime. Still, these guys take baby-making really, really seriously.

Why? The stakes are pretty high. Female redbacks can live for two years and store and use their mate’s sperm for their entire lives, passing their mate’s genes on to thousands of offspring.

A male redback spider begins his baby-making quest by inserting sperm packets into two appendages on the front of his head called “palps.” Then he finds himself a lady redback spider, who is 50 times his size (by weight). The male stands on the female’s abdomen and inserts one palp into one of her genital openings, then—using the palp as a pole—he pole-vaults himself into the female’s jaws. The female pierces the male’s abdomen and injects digestive enzymes. (In other words, she starts eating him.) The male then returns to his starting position, inserts his other palp into the female’s second genital opening and vaults himself into her mouth once again. This time, she eats him.

Is it really worth it? Evolutionarily-speaking, yes. Researchers found that males who were eaten mated twice as long and fertilized two times more eggs than the few males who are left uneaten. Plus, females who ate their mate were unlikely to mate again, meaning that the eaten male’s genes were the only male genes that female would be passing on to the next generation. In the end, even though the male dies a horrible death, he wins.

 

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Cool Critter: Solenodon

March 11, 2009 at 7:02 pm · Filed under Cool Critters, endangered species and tagged: , , , , ,

Imagine a mammal that looks like a toupee-wearing cross between Yoda, an aardvark and an R.O.U.S. Now, imagine that this mammal can inject immobilizing venom through its teeth. That animal would totally rule the world, right?

Ummm, no. Meet the solenodon, a remarkably clumsy nocturnal insectivore with teats on (or at least very close) to its butt.

Solenodons are found on two islands in the Caribbean: Cuba and Hispaniola (the island shared by Haiti and the Dominican Republic).* The two species are distinct—they haven’t gotten it on in 25 million years—but they look similar. Both have long flexible snouts, teeny tiny eyes and long finger-like claws. They have naked tails and feet, but are otherwise covered in multi-colored fur. Hispaniolan solenodons are slightly larger than their Cuban cousins at a maximum length of 13 inches and a max weight of 2.2 pounds.

Solenodons have been around for-evah (in teenage time). Evolutionarily speaking, solenodons’ ancestors diverged from all other mammals 76 million years ago. They were one of the few native mammalian species to survive the European colonization of the West Indies, but times have gotten tough for these so-ugly-they’re-cute critters.

Like most extremely endangered animals, solenodons are threatened by habitat loss and predators and—like endangered whales—they just can’t reproduce fast enough. Solenodons live in forests, but with deforestation rampant on Caribbean islands (especially in Haiti where 99 percent of the original forest has been destroyed in the last 200 years), the little forest that remains is fragmented. For a relatively solitary animal, fragmented habitat can make finding a mate very difficult. Even if a solenodon is lucky enough to find a sexy solenodon of the opposite sex, the species’ reproductive rate is low. Females produce one or two litters of one to three offspring per year.

Scientists think that Hispaniolan solenodons were once one of the dominant carnivores in Hispaniola. But then the Europeans introduced dogs, cats and mongooses (mongeese?) to the island. Against these vicious—or at least competent—predators, the slow and awkward solenodon doesn’t stand a chance. 

Of course, teetering on the brink of extinction doesn’t make a critter cool. But being the only living mammal that can inject venom through its teeth sure does. Solenodons have modified salivary glands in their mandibles (jaw bones). These salivary glands produce venomous saliva that the solenodon can inject into a victim through a grooved tooth—one of the lower incisors.

This venom-injection system is more of a self-defense tool than a hunting tool. Solenodons feed primarily on insects, worms, snails and plants—none of which really need to be subdued with immobilizing venom. Occasionally, solenodons supplement their diets with reptiles and chickens, but scientists aren’t sure if they actually attack and immobilize living animals or just scavenge dead ones.

Now, what’s up with those oddly-positioned teats? Most insectivores carry their young in their mouths, but young solenodons stay with their mothers for a long time and actively carrying the little buggers around could become tiresome. (And, of course, mama solenodons’ mouths are equipped with venom-injecting teeth, which may or may not immobilize their young.) Instead, young solenodons conveniently dangle from their mother’s teats in a highly evolved system known as ‘teat transport.’ The system is simple: baby solenodons grab on to their mother’s teats and hang on. Very young solenodons just hang as their mother drags them along. Older offspring grab a teat and walk under, beside or behind their mother.

 

*Until their re-discovery last year, scientists thought the Haitian population of solenodons was extinct. Now, they think the Haitian solenodon is a subspecies of the Hispaniolan solenodon—or perhaps an entirely different species.

 

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Entangled Energy

March 4, 2009 at 9:41 pm · Filed under alternative energy, endangered species, marine science and tagged: , , , , , , ,

Remember those resourceful Dutch people we told you about in October? Life gave them lemons (in the form of 1.2 million pounds of chickensh*t) and they made lemonade, or, more accurately, 270 million kWh of electricity.

Golly, if we burned all of our excessive crap, we’d have a lot of energy…and a lot of crap-ashes.

Well, guess what: poop isn’t the only kind of crap that can be turned into power. Other kinds of waste (i.e. garbage) work too. Energy-from-waste programs burn garbage to create electricity. In general, burning one ton of waste produces 520 kWh of electricity. While the process of burning something (anything) produces greenhouse gas emissions, burning garbage prevents the methane production that would occur in a landfill. (Methane has a rep as a pretty potent greenhouse gas—significantly more potent than carbon dioxide—and landfills are the largest source of methane emissions in the U.S.) The claim, according to the folks in the garbage-burning business, is that every ton of trash combusted in an energy-from-waste facility actually prevents the equivalent of one ton of CO2 from being released into the atmosphere.    

Perhaps more important than the questionably brilliant concept of burning crap to curb climate change, however, is the origin of the crap. A small, but very important, part of the “waste” in the waste-from-energy equation comes from the ocean. Officially termed “marine debris,” this ocean crap raises a lot less havoc when it’s on dry land.

Derelict fishing lines and nets (known as “ghost nets” because they continue to catch fish even when they’re abandoned) haunt every ocean. Wayward fishing gear destroys delicate corals as it bashes against coral reefs and causes serious damage as it wraps around everything from sea turtles to cetaceans—and even boat propellers.

North Atlantic right whales, in particular, have a bad habit of getting tangled up in fishing gear. (They also have a tendency to get hit by ships and were once known as the “right” whale to kill because they were such an easy target for whalers and floated to the surface when killed.) Scientists estimate that at least 72% of the North Atlantic right whale population has been entangled at some point and that 10-20% of the population becomes entangled each year. So far this year, scientists have counted five entangled right whales (compared to the typical one or two), which is kind of a big deal for a population of 300-400 animals.

Right whales* may not be the brightest crayons in the box, but we can’t make them smarter or teach them how to slalom through ex-fishing gear. We can, however, get rid of some of the gear that’s crowding their ocean. Through a Hawaiian program called “Nets to Energy,” a mainland program called “Fishing for Energy” and a New Hampshire initiative known as the “marine debris to energy project,” fishermen and marine debris specialists have yanked tons of ratty old fishing gear out of the oceans. Since 1996, more than 760 tons of decrepit fishing gear has been pulled out of the Pacific waters surrounding the Hawaiian Islands. On the mainland, 11 Northeastern ports participated in the first year of Fishing for Energy and collected more than 123 tons of gear. The New Hampshire program is the youngest, smallest, and most poorly named. Still, the program collected 3.8 tons of marine debris in its first six months.

Is there a moral to this story? Absolutely. When life gives you lemons or poop or marine debris, make lemonade (or an appropriate alternative).

 

*Right whales aren’t the only large whales that get entangled. Between 2002 and 2006, there were 145 entanglements of large whales—mostly humpback and minke whales—along the U.S. east coast, adjacent Canadian Maritimes and the Gulf of Mexico coast. 

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