Fisheries technician Wes Hartman (left) and lead biologist Ben White tag a female coho in preparation for spawning at the Warm Springs Hatchery. The tag will help match the female with males that have been selected as mates through genetic screening. Credit: Brandon Beach/U.S. Army Corps of Engineers

A short history of California salmon: Glorious past. Grim present. Dark future. Now, the story I just got done working on for QUEST Radio is about the crisis of coho salmon along our coast. But that short synopsis applies as well to coho in other parts of the state and to their larger and perhaps better-known cousins, the chinook. Wherever you look in California, salmon are in serious trouble if they have not already disappeared. It's evident that their biggest problem is having to live alongside us. Our needs and our ability to exert our will on the world around us–to dam rivers and streams, to clear forests, to replace entire ecosystems with new ones of our own making–has wrought havoc on many species.

The collapse of salmon populations is just one example. Some of the people working to preserve and restore coho along our coasts feel that history–both the natural history of the salmon and their role in human history–can be a powerful teacher and could help save the wild fish from extinction. An egg being squeezed from the vent of a female coho salmon at the Warm Springs Hatchery. Biologists at the facility examine the eggs as part of the process of determining when the females are ready to spawn. Credit: Brandon Beach/U.S. Army Corps of Engineers Biologist Rory Taylor checks on a tray of coho salmon recently hatched at the Warms Springs facility. The coho here are called "alevin"–the salmon's earliest life stage. They'll be reared in the hatchery, then planted in tributaries of the Russian River. Credit: Brandon Beach/U.S. Army Corps of Engineers

Charlotte Ambrose, the National Marine Fisheries Service biologist in charge of coordinating an upcoming recovery plan for coho along our coast, says she has this intertwined history uppermost in her mind. In fact, the draft of the 4-inch-thick recovery plan she's been working on starts with a chapter on the coho's history. Ambrose calls it "a renegade move" to open the document that way, but she says she feels it's crucial to understand the past vitality of coho on the California coast.

She's fond of quoting a 1930s account of a coho run on Northern California's Garcia River: "The water was like glass … the salmon were in rows … they lay there still … every now and then one would wiggle its tail to keep his place in line. They lay there by the thousands as far as my eye could see." That's the glorious past of the coho.

But Ambrose points out that even in that lost age, coho showed a remarkable ability to handle adversity. Drought, flood, or fire might devastate a watershed and wipe out a run. But far from being "hot-house flowers," in Ambrose's phrase, coho are survivors by nature. They're prolific breeders–a single female will lay 2,000 eggs or more in its streambed nest. If they find their natal streams unreachable, they'll wander to new spawning grounds.

Ambrose thinks an understanding of the coho's history–its ever-present drive to perpetuate itself, and its past abundance–are key elements to getting people to act to save the fish. And she says small steps to improve the odds of salmon survival can be as important as sweeping ones. "It’s like a small pebble in a pond. One small action can make a tremendous difference in increasing the probability of survival of the young, of the adults, of the eggs, of the out-migrating smolts." If we want to rewrite the next chapter of the coho's story, she suggests, get to know your watershed, and go out and volunteer to help repair it.

Listen to Saving Salmon radio report online.

Comet Wild 2, as imaged by NASA's Stardust spacecraft.Nothing seems to capture the pure grandeur and extra-Earthly splendor of outer space like a comet: pure white cosmic snow, shining brilliant in the Sun's radiance, a vastly long tail of silky celestial gossamer…unreachable, untouchable, unspoilable….

Well, at Chabot, we like to bring things down to Earth a bit—not to diminish their wonder and awe-inspiring beauty, but rather to give us a chance to connect with pieces of the Universe in a personal way that—we hope—will only enhance their wonder.

Such it is with the Personal Comet. We make them in our classrooms, and our teen volunteers—Galaxy Explorers—sometimes set up a table in our exhibits to make comets for our visitors.

Last week I was teaching a lively group of 3rd graders our class, "Shooting Stars" (I'm not the usual teacher for this class, but love teaching this one especially).

"Let's make a comet," I announced, receiving a classroomful of suddenly puzzled 8-year-old faces. "Follow me." I led the group to the back of the room and had them sit in front of our rolling comet kitchen, tying on an apron and donning the "Comet Chef" hat.

"What's in a comet?" I quizzed. Hands went up, and answers were plucked out. "Water." "Ice." "Very small pebbles."

"Good answers. Let's start cookin'…."

One by one, and two at a time, I called up volunteers (no lack of these at all) to add ingredients into the mixing bowl.

Water first—two cupfuls. What else? The Chef helped out his students a bit: pebbles are fine, but what are they?

Silicon, calcium, to name a couple—so we add a source of these: sand. Then, iron, and magnesium—two more known comet constituents. Source? Dirt! Dirt can contain these, among other things.

For the carbon in our comet, we added—carbon: black charcoal dust; just a dusting.

There is nitrogen mixed up in comets too, so we had to add some to our concoction. Our nitrogen source (other than all the gaseous nitrogen floating about us in the air) is ammonia—NH₃ (what's a little hydrogen in the compound, more or less? In fact, ammonia itself has been detected in comets, so our recipe is true).

Organic compounds—carbon based organic molecules—have also been detected in comets…so we add a couple glugs of corn syrup. Okay, that's cheating a bit, because comet organics aren't known to come from agricultural products….

And lastly, but not leastly, is the two-in-one ingredient: contained in a plastic bag, I had the class use mallets to pulverize a few cupfuls of dry ice pellets into a fine powder. This adds not only the carbon dioxide to the material makeup of the Personal Comet, but that which really makes the difference between a bowlful of slightly sweet mud and the astral nugget of a comet: COLD! Space is cold, and so is dry ice.
In goes the frigid, dry frost, and out erupts clouds of billowing vapor—very exciting stuff. Now the Chef had to work fast, stirring and mixing and shaking the brew, and then squeezing the convulsive mixture in its plastic bag, with gloved hands, into a hard, solid lump. It takes a lot of squeezing, as it turns out….

Is it done yet?

I pulled out of the bag our Personal Comet, holding it out for the kids to marvel at—and they did. The double-fist-sized, dirty whitish, somewhat gritty hard blob is covered with pits and knobs and spouting plumes vapor. And, magically, it looks almost identical to a photograph of the nucleus of comet Wild 2, taken by NASA's Stardust spacecraft some years ago.

Everyone got to touch the comet—quickly, because it was quite cold—and make a personal connection with a tiny piece of the heavens. Now, I think, these kids are armed with an experience that will make their first comet-observing experience (yet to come for many of them!) a bit deeper, as I hope when they do see the vastly awesome sight in the sky, or through the eyepiece of a telescope, they'll also remember what it's like to touch a comet, or smell a comet, or see one spouting vapor right before them, in the palm of their hand….

Perhaps no single development of the last century has been more influential or more important than the laser.

The concept of discovery is a powerful sentiment in science. Television’s Discovery Channel and print journalism’s Discover Magazine have folded the word into their identities, and as a child that my iconic scientist was a paleontologist, literally unearthing discoveries of the prehistoric wilderness. Just as motivating, however, is the concept of invention, and perhaps no single development of the last century has been more influential or more important than the laser. In 2010 the laser turns 50, and to celebrate, a group of organizations including the American Physical Society, the Optical Society, SPIE and IEEE Photonics Society have organized a year-long series of events this year dubbed LaserFest.

UC Berkeley has been celebrating LaserFest this past week with special exhibits and events over the weekend at the Lawrence Hall of Science, and a special lecture on Monday the 25th by Roger Falcone, Bob Byer, and Nobel laureate Charles Townes, also at the Lawrence Hall of Science.

Theodore Maiman built the first laser out of a rod of pink ruby in 1960. However, the laser’s precursor and underlying principle belongs to Townes. In 1954, he and colleagues constructed the ammonia maser, a stunning proof-of-principle device demonstrating that intense beams of light within a narrow color range could be produced. A flurry of excitement and research efforts followed aimed primarily at developing masers that could work at higher and higher frequencies of light.

As maser research matured the name changed as well. A high-frequency MASER (the acronym stands for microwave amplification by stimulated emission of radiation) became the optical MASER. Then at a conference in 1959, Gordon Gould coined it as the LASER. (The L stands for light.) One of the conference’s organizers, Arthur Schawlow, rebutted that these new devices would be more important as oscillators rather than amplifiers, so perhaps they should really be calling it the LOSER (see the recent article in Physics Today). Curiously, substituting the O never caught on.

The laser’s influence in science and society, however, has been dramatic. We use lasers to read our hard drives and play DVDs. We use them to improve our vision. Lasers play an integral role in security systems. They are a crucial component of our ability to keep time accurately. The world’s biggest laser in Livermore could be on the verge of igniting fusion reactions. We even shot a laser at the moon, waited for it to bounce back, and used the information to calculate the moon’s distance to the Earth with unprecedented accuracy.

Time will tell what the laser’s future applications might be. Personally, I am rooting for a sign of extraterrestrial life from the SETI optical telescope. The research collaboration’s website says that “A tightly focused light beam, such as a laser, can be 10 times as bright as the Sun and be easily observed from enormous distances.” Then again, if the aliens do decide to shoot a message our way via laser, let’s just hope that that they don’t decide to crank up the power so high that we all get vaporized.

The particulate from diesel trucks, which contains a number of carcinogenic compounds, can also cause lung cancer.

Wondering how much soot is in your city's air right now? Find out through the Bay Area Air Quality Management District.

As I write this, it's rainy outside, which is a good thing from an air quality perspective. Rain keeps the dust, or particulate matter (that's "PM" in air quality jargon), glued to streets and cars, and out of the air. Here in San Francisco, our PM 2.5 value is seven — seven micrograms of soot for each cubic meter of air. That's pretty clean, so breathe deep.

Using the calendar on the left side of the page, check out the levels from January 8th — a day where the average PM 2.5 level was 52 — and you can see why the Bay Area Air Quality Management District declared January 8 a Spare the Air Day.

So what do these numbers mean?

PM 2.5 refers to the smallest soot particles that air officials measure – each particle is about 1/70th the width of a human hair. These particles are so small, they're invisible to the naked eye. They're small enough to travel deep into the delicate alveoli, or air sacs, in our lungs, where they can cause or exacerbate asthma and other breathing problems. From there, they can make their way into our bloodstream, leading to heart attacks and strokes. The particulate from diesel trucks, which contains a number of carcinogenic compounds, can also cause lung cancer. (Check out this excellent Q&A on the hazards of diesel soot.)

The black numbers describe the current level. Blue and red figures describe the change from that same hour, the day before.

When you look at the chart, check out the PM numbers for West Oakland, right next to the Port of Oakland. These are what air officials point to when asked to justify the new rules for Port truckers, which this story, and this one, describe. A few years ago, the BAAQMD conducted a detailed health assessment of West Oakland residents, finding cancer rates three times the Bay Area average. In this week's radio story, we also cite a 2008 Harvard study on lung cancer rates in truckers. Here's a story about the study, and the study itself.

Poke around the QUEST website a bit and you'll find an abundance of media on this subject. Start with Gabriela Quiros's terrific TV story, "Perilous Diesel." Gabi's also taken a closer look at some of the mysteries surrounding childhood asthma in another TV piece, "Asthma: What Brought on the Epidemic?"

Last but not least, here's a slide show of scenes from this week's radio QUEST story, featuring characters and scenes from several sides of the campaign to reduce diesel soot.

Listen to Truckers Clean Up Their Act radio report online.

One of the most amazing aspects of the cuttlefish is their skin. The skin contains up to 200 pigment cells per square millimeter that enables it to change its camouflage at will.

I have been working for the California Academy of Sciences for five years now this month. I have always held a fondness for the aquarium. On my first day of work, I took a tour with other new hires through the aquarium at Howard Street. We stopped at the giant sea bass’s tank. It was feeding time and we were given sardines to feed him. We were instructed by one of the biologists to hold the fish in two fingers just beneath the surface to let him suck the fish into his mouth. When it was my turn, I dutifully held the fish under the water and watched the huge fish round the tank and head my way. He approached quicker than I had anticipated and I got spooked. So I lifted the fish out of the water. Well he still sucked the fish up; but he also sprayed me with salt water and fish guts. So I started at the office, dripping in salt water and smelling of sardines.

Tonight after work, I descended down into the Steinhart Aquarium. It’s kind of an after-work tradition to tour the aquarium before heading home. I like to stop by and see the same giant sea bass that drenched me and the octopus next door when the lights have been dimmed and the halls are empty. I now often stop at the dwarf cuttlefish tank. Tonight, one of them was swimming around the top of the tank, shimmering in a varied and beautiful color display. The other dwarf cuttlefish was resting at the bottom of the tank, expertly matching the rocks around it.

One of the most amazing aspects of the cuttlefish is their skin. The skin contains up to 200 pigment cells per square millimeter that enables it to change its camouflage at will. It also has muscles in its skin that enable it to change its skin from smooth to rough. Different species of cuttlefish can change the color and texture of their skin to blend in with the environment around them, display spikes and bright colors to ward off predators, or even create a strobe color display to mesmerize prey.

As well, cuttlefish, part of the Cephalopoda family that includes squids and octopi, have one of the largest brain to body ratios of any invertebrate. They can take in input from sight, smell and sound in the form of pressure waves felt through their lateral lines. The reaction of color displays has demonstrated problem solving and biologists study them to learn more about invertebrate and possibly human intelligence.

I now keep a closer watch on this tank, in hope of seeing the new generation of dwarf cuttlefish. The Academy is the first aquarium in the US to have a captive breeding program for dwarf cuttlefish, Sepia bandensis. The program, launched by Academy biologist Richard Ross offers the Steinhart Aquarium and other institutions the chance to feature a species, which is both captivating and less resource-intensive to keep than larger cuttlefish species. Dwarf cuttlefish span only two to four inches in length. “By establishing a stable breeding population,” Ross notes, “our hope is to make it easier for aquariums to showcase cuttlefish and their remarkable characteristics without impacting wild populations.” It’s no wonder that traveling through the Aquarium has become my favorite part of the day. Even after five years of wandering, I still see something amazing with every visit.

For some great footage of cuttlefish in the wild, along with information about research on cuttlefish and an overview of their anatomy – visit this great site provided by NOVA.

It can be hard to tell which science is good, bad, or ugly on the web.

I have often thought that the percentage of good scientific information on the web must be pretty low. So I decided to test the idea out on a question I was recently working on.

Someone asked me if humans started out with O blood type and then only later developed A and B.  A quick look at PubMed showed that this was not the case.  Most of the recent genetics studies point to A coming first, followed by B about 3.5 million years ago and then, finally, about 1 million years ago, O.

This makes some intuitive sense if we think about what A, B, and O are.  O is a form of A that doesn’t work any more because of a mutation*.  This makes the idea that a broken gene came before a working one pretty unlikely.  Not impossible, just not all that likely.

Now I researched this answer the way I usually do—I headed straight for PubMed to get the hard scientific data.  I can do that because I work for Stanford and so have access to lots of journal articles and I have the scientific background to decipher the geneticsese these reports are written in.

What I also did this time was to try to find the answer without PubMed.  I started out on Yahoo searching for human blood type evolution.  Yikes.

Links 1, 2, and 7 talk about primate A and B blood types.  Gorillas have B and chimpanzees have A and a bit of O.  From this the authors try to conclude that we are somehow a mix of these two…perhaps gorillas and Neanderthals are closely related to each other and so are chimps and Cro Magnon.  In this scenario, humans come from a mix of Cro Magnon and Neanderthals.

This is certainly not the case.  Gorillas do have a blood type similar to B but it isn’t the same as ours at the gene level.  And if current evolutionary history is to be believed, we split from gorillas way before our B blood type was born.  So we did not get our B from gorillas.

Also, chimpanzee O is not the same as our O…it developed well after we split as well.  We even know that Neanderthals have our O blood type and not a chimp’s (and certainly not a gorilla’s!).

Links 3, 5, and 9 use blood type genetics to show that Adam and Eve could have founded the human race.  Links 4, 6, and 8 talk about the blood type diet.  And link 10 connects blood groups to aliens.

Google does a bit better.  You get eight similar links but you also get an NPR piece that does pretty well and a Dawkins forum comments piece that can get you to the answer eventually.  However, you have to wade through a lot of stuff to get there and you only know to home in on the comment with the correct information if you already know the right answer.

Obviously what is popular isn’t always what is right.  (And the prize for stating the obvious goes to Dr. Starr!)  I thought I’d try Wikipedia next.  Wikipedia can have many factual errors but it often gets the overall story line correct.  Unfortunately there isn’t an article on this subject.  There is on one the blood type diet though…

So what is a non-scientist to do?  There don’t seem to be a lot of options.

There are websites like mine at Understanding Genetics that try to give the real scoop on what current science says about various issues.  But they tend to focus on a single topic and don’t often appear at the top of a website search.  (Understanding Genetics is an exception in that it gets enough hits to often be on the first or second page if the query is worded in the right way.)

I am not sure what the answer is to getting better science via the web.  Maybe we need a web based encyclopedia about science written by scientists.

The tricky part will be to get them to do it.  And to have it make sense to anyone but another scientist in that particular field.  And for them to do it impartially.

I’m curious how other people find their science online.  And how they make sure it is reliable.

* This isn’t weird, blue eyes and red hair work the same way.

Gullies in wall of Hale Crater. Credit: NASA/MROOut of about 40 robotic missions launched toward Mars since the early 1960's, about 17 of them have been successful (I say "about" to hedge my bets, because the "success" of some of those missions is a bit gray), and of all of those, three orbiters, two rovers, and maybe—MAYbe—one lander are still active.

Here's a quick status on the active ones:

Mars Reconnaissance Orbiter: The most recent arrival at Mars (2006), MRO's 5-year mission (hmmm—sound vaguely familiar?) is to study the history of water and climate on Mars, as well as to serve as a telecommunications relay for other spacecraft. Armed with a suite of powerful instruments to study the atmosphere, surface, and subsurface of Mars—including a camera, HiRISE, that can almost read the license plates on Martian automobiles—MRO has to date sent back more data than all other Mars missions combined. It's not been a glitchless flight, however: in 2009, MRO's computer reset itself four times for unknown reasons; the last reset, in August, was followed by a 4-month operational hiatus as Earth-side controllers performed some careful programming updates to help guard against effects of any future resets. MRO resumed operation in December.

Mars Odyssey 2001: NASA's 2001 Odyssey is still going fine after nine years—although the computer glitchiness out around Mars seems to be catching: Odyssey's computer put itself into a safe mode last November 2009 in response to a memory error. This was corrected and Odyssey has resumed doing science. Among Odyssey's major discoveries was the detection of huge expanses of water ice just under the surface of polar lowlands, and the surveying of deposits of water-related minerals in various locations around the planet.

Mars Express: Arriving at Mars in 2004, Mars Express became the European Space Agency's first mission to another planet, which was recently extended to 2012. Though the Beagle 2 lander component of the mission fell to Mars and was never heard from again, the Mars Express orbiter has sent back years of captivating images and important data, including the confirmation of methane in Mars' atmosphere (whose source is in all likelihood subsurface, and the origin of which—organic or inorganic processes—is being debated).

Mars Exploration Rover Opportunity: After six years of crawling around Meridiani Planum discovering chemical and geological evidence for past water on Mars, Opportunity is now on a long march to a large impact crater, which it will reach (if it can keep on running) in about two years. Currently, the rover has stopped to RAT out chemical and geological information from a rock called Marquette Island—the RAT is its rock abrasion tool, or rock grinder. Still going….

Mars Exploration Rover Spirit: Also still alive after six years—almost 25 times longer than it was planned to run—Spirit has been stuck in a sand bog for the last six months. With a couple of wheels on the fritz, Earth-side operators have been confounded in trying to free the robot—but Spirit has continued to make scientific measurements anyway…and in fact made a significant discovery in the course of trying to get unstuck.

Phoenix lander: Although it's been in the deep dark freeze of a Martian winter since November 2008, the Phoenix lander has an outside chance of survival. Now that light is returning to Phoenix's landing site, NASA is listening for the robot's radio signal, in case the return of solar power means that Phoenix will rise from the frost and live again! So far, no such signal….

Next up: The Mars Science Laboratory rover, "Curiosity."

Staff at the International Bird Rescue and Research Center caring for oiled birds.

When two gigantic oil tankers collided near Golden Gate Bridge in 1971, more than 900,000 gallons of oil were spilled into the waters of the San Francisco Bay. Thousands of birds and animals were covered in oil and in great danger. Rescue centers to the scale that were needed did not exist. Concerned citizens and professionals snapped to attention and set up emergency centers, one being a facility in Richmond. Alice Berkner was one of those citizens and she was inspired by the efforts of the crew. As a registered nurse, she was also filled with ideas of how to improve on this brand new field. Alice and a group of volunteers were compelled to find the solution that worked best for future injured wildlife and The International Bird Rescue and Research Center (IBRRC) was born.

The center has since been working non-stop to save wildlife that suffers from oil spills and other disasters. In 2001, IBRRC helped to open the state-funded Oiled Wildlife Care and Education Center in Cordelia (Fairfield), California at the northern end of San Francisco Bay, a key facility in California's Oiled Wildlife Care Network. This facility contains IBRRC's new headquarters and the International Training Center for Oiled Wildlife Response. Their work includes training volunteers, consulting with the petrol industry, and managing a professional emergency response team. Their efforts have covered over 200 oil spills in 11 states, including the 1989 Exxon Valdez oil spill in Alaska. A southern rescue center in San Pedro, Los Angeles also contributes to the efforts.

What makes oil spills so toxic for birds?

Birds are made to be buoyant in the water, light in the air and warm and insulated wherever they go. Oil penetrates and opens up the structure of the plumage of birds, reducing its insulating ability, making the birds more vulnerable to temperature fluctuations. It also makes them heavy and less able to float above the water or take off for flight. In this exposed condition, they are unable to escape from predators or find food. As they attempt to preen themselves, they ingest the toxic substances. Unless there is human intervention, most birds affected by an oil spill do not survive.

Fortunate for those birds, and for us humans who are lucky enough to share the planet with them, organizations like the IBRRC exist and are powered by passionate wildlife heroes, like Jay Holcomb.

Jay Holcomb has served as director of the center for the past 24 years and has many amazing stories to tell, from pelicans to penguins.

You can hear these stories at, "Saving Seabirds – Stories from the Frontline" with Jay Holcomb of the International Bird Rescue Research Center. This will be an inspiring benefit presentation by Jay on January 28th at the Oakland Zoo. All proceeds from this event will go support future bird rescue efforts.

Discovered an oiled bird?
In California, call the Oiled Wildlife Care Network at 1-877-823-6926.

Interested in volunteering? Classes are available.

The Rice Solar Energy Project will produce enough electricity to meet the demand of 60,000 households—about 150 megawatts—beginning in 2013. Click here for a full-size version of the diagram. Courtesy of SolarReserve.

In a world energy landscape dominated by coal, gas, oil, and nuclear, renewable energy sources such as wind and solar don’t stand a chance if we can’t find a way to store energy when the sun doesn’t shine and the wind doesn’t blow. In my last blog entry, I wrote about storing electric energy in a battery made of paper and nanotech ink (see The Paper Battery Chase). But it isn’t necessary to store electric energy. We can create hydrogen, using electricity generated from photovoltaic panels, and then use the hydrogen to fuel a fuel cell, which recreates the electricity. The Leaf Community in Italy is experimenting with this process. And energy changes forms in other ways. We can store heat from the sun and use it to create electricity in the dark. As in any energy storage and conversion process, if we can do it without losing too much energy in the process, we can add another tool to our renewable energy toolbox.

I add a little salt to the water when cooking spaghetti—it raises the boiling point so that you can cook the pasta more quickly, although I’m not sure it makes a big difference. Mostly I add salt to make the spaghetti taste better. The properties of a liquid salt—a mixture of sodium nitrate and potassium nitrate—are a little different. This liquid salt will store heat up to a temperature of 1,000⁰F, which is much higher than the boiling point of water, 212⁰F at sea level. The Pacific Gas and Electric Company, (PG&E) has contracted with SolarReserve LLC to store energy using liquid salt. The Rice Solar Energy Project will produce enough electricity to meet the demand of 60,000 households—about 150 megawatts—beginning in 2013.

The Rice Project uses a large circular field of mirrors to reflect light onto a central tower. Liquid salt is circulated through the tower and, once heated, it is stored in an insulated tank. When the sun goes down the liquid salt will still be able to heat water well past the boiling point to create steam, which can be fed into a conventional steam turbine to produce—Walla—electricity. The liquid salt, now cooled, is stored in another tank and is ready to begin the process all over again.

Take that coal, gas, oil, and nuclear!

Transforming food waste into energy could be a good investment, both environmentally and economically.

When I first considered reporting on a food scraps to energy program I wasn't really thinking of the smells I would encounter. Granted it's not nearly as bad as raw sewage, but 25 tons of decomposing food can pack a punch. Then I saw the sludge and thought what a nightmare for folks who can't stand their foods mingling on the dinner plate. Fortunately, I have a strong stomach.

The story intrigued me because it seemed like converting food waste to methane for energy use was a no- brainer. Why isn't everyone doing this? So far the program, run by the East Bay Municipal Utility District, seems like a success but as it turns out there are a few challenges, which may explain why it's not so widespread.

First, the wastewater plant in Oakland has to deal with non-organic items that accidentally wind up in restaurant green bins, such as forks, plastic wrap, even pennies. These pesky interlopers damage grinders and other machinery and are a constant and costly headache for the utility. That's why the agency wants more control over the sorting and is planning to bring the process on site. Right now the haulers and the restaurants control the pre-sorting process.

Then there's the question of how easy this program can be replicated at other wastewater plants. The East Bay facility already had the infrastructure and capacity to take on this program. It's investing to expand it, but some plants don't even have these anaerobic digesters and those that do may or may not have the ability to produce electricity. This could well require costly investments in tough economic times.

Then there's the buy-in needed by the community. The Bay Area is a mecca for food and green consciousness. It doesn't take much to get some portion of restaurants to jump on board. But even here in the Bay Area some have dismissed the program as a hassle. So you can imagine taking it to another part of the state or country where it might well meet with eye rolling and some "so Berkeley" comments.

There's also some environmental fallout from this process. When the plant burns methane for energy it creates carbon dioxide, another greenhouse gas. But methane is some 23 times more potent that Co2. So It's better to capture and use the methane. The U.S. Environmental Protection Agency says the Co2 is a lesser of two evils.

In fact, the Agency is not dissuaded by any of the challenges. It's pushing the food waste to methane program to other wastewater treatment plants nationwide. It's even putting together a "toolkit" to show why it could be a good investment, environmentally and economically.

Listen to Power Up With Leftovers radio report online.