Aphrodite’s Commute (or, the Transit of Venus)

As we wind up our year in the UCSC Science Communication Program, it’s a time of transition. Not only for the ten of us, as we wrap up our final stories, multimedia projects, and internships, but also for the solar system. This week marks a rare celestial event, which happens just twice every hundred or so years: the transit of Venus.

Photo of the 2004 transit of Venus (photo by Mswggpai, Wikimedia Commons)

Earth’s fiery twin will cast a tiny black dot as it crosses in front of the Sun on June 5th or 6th, depending on where in the world you’re viewing it. Here in North America, it takes place June 5th, starting at 3:06pm in California. The last transit occurred in 2004, and this year’s will be the last your lifetime, as the next doesn’t occur for another 105 years. See the end of this post for tips on watching it.

The transit of Venus isn’t merely an astronomical curiosity – it played a crucial role in measuring the size of the solar system. A Brit named Jeremiah Horrocks first calculated and observed the transit in 1639, along with his friend William Crabtree. Horrocks turned his room into a giant pinhole camera, by putting a piece of cardboard with a hole cut in it in his window and projecting the black dot of Venus onto a white sheet. By measuring the size of the dot of Venus, Horrocks calculated the distance between the Earth and Sun to be about 60 million miles (97 million km). His number was only two-thirds the actual distance, 93 million miles (150 million km), but it was closer than any previous estimate.

Fellow Englishman Edmund Halley later described how to obtain a more precise estimate of the size of the solar system, which involved timing when Venus slid past the Sun’s borders. Yet Halley wouldn’t live to see the next Venus transits in 1761 and 1769. Transits occur in a pattern of 8 years apart, then 121.5 years, then 8 years, then 105.5 years. The whole pattern repeats every 243 years. The 1769 transit marked a major milestone in international scientific collaboration, because Halley’s calculations required observations from scientists around the world. One observer was the explorer Captain Cook, who voyaged to Tahiti to observe the transit as part of a secret mission to explore Australia.

Unfortunately, they had a tough time timing the exact entry and exit of Venus on the face of the Sun, due to something called the “black drop effect.” At the time when the black disk of Venus was just passing the Sun’s inner edges, a black teardrop shape appeared, connecting Venus to the Sun’s border. The effect is thought be caused by optical disturbances in the Earth’s atmosphere or the viewing apparatus.

Nevertheless, observations since then honed the estimate of the solar system’s size, which modern methods such as radio telemetry and radar have confirmed.

So why not turn your eyes skyward as Venus waltzes through the glare of our Sun next week. Here are some tips for viewing the transit:

• Here’s a map of places where the transit will be visible

• You can find out your local transit time here, **keeping in mind that daylight savings time adds an hour to the times shown.

• Not surprisingly, it’s not a good idea to stare directly at the Sun. Use proper eye protection.

• The best way to see the transit is with a telescope or binoculars with a solar filter. Failing that, you can use eclipse glasses or #14 welding glasses, or even a pinhole camera. You won’t be able to see subtle effects like the black drop with these methods, though.

• For a fun and engaging history of the transit, listen to the Big Picture Science radio show and podcast “Mass Transits”.

This will be my last post for this blog. Like Venus, our SciCom program has come full circle. It’s been a pleasure learning the craft of science writing here among the Central Coast redwoods. To all reading this, best wishes on your own transits!

Math, Engineers, Bridges, and Hand Waving

By Steve Tung

After seeing the alarming video of the Minnesota I-35 bridge collapse in class today, I’m reminded from my recent reporting on the flattening of the Golden Gate Bridge 25 years ago on how flexible numbers can be. Searching for a simple detail revealed how much hand waving goes on that I hope is reserved for the press and not actual analysis.

In 1987, hundreds of thousands of people crammed onto the iconic Golden Gate Bridge. Image from wikimedia commons, taken by Cary Bass.

To quickly summarize: hundreds of thousands of people crossed the Golden Gate Bridge on foot to celebrate its 50th anniversary. The weight, more than two times of cars in bumper to bumper traffic, was enough to make the middle sag 7 feet, flattening the suspension bridge’s slight curve.

The number I was looking for was pretty simple: just the amount of weight the bridge was designed to support. The original design load of 4,000 pounds per foot of bridge is pretty well documented, but renovations during the mid-80s removed a dense concrete layer and replaced it with lighter and stronger steel frameworks. Those renovations should have boosted the design capacity of weight, and I just wanted to know what it was. But no one I talked to (including officials and engineers that oversee the bridge) could tell me what that new number was. More surprisingly, three of the four engineers I talked to for the story gave me starkly different ideas about the bridge’s strength and how to think of it that day, none of which particularly agreed with the chief engineer’s numbers as reported by the Merc at the time. (The other engineer I talked to recused himself from analysis because he wasn’t familiar with the Golden Gate’s particulars).

Off the bat, all the experts agreed that it would be practically impossible for the Golden Gate to break and drop people to their deaths from simply cramming more and more weight onto it. But they disagreed at the point where

the bridge would start getting damaged– at what load metal might start to permanently bend (like a bent paper clip), rivets might break, joints get overstressed, all which would require maintenance.

According to the Merc’s story in that era, the day after the bridge flattened, the bridge’s chief engineer said that the bridge was no where close to being damaged. He said that the bridge was designed to hold 5,700 pounds per foot of bridge, while the crowd weighed about 5,400 pounds, using rather generous estimates. But even then there’s a buffer where the bridge can gain even more weight without any deleterious effects. Some engineers call it the factor of safety. “There’s no way we could have gotten enough people on the bridge to cause any problem,” the chief engineer said at the time.

But now, one engineer insisted that the bridge was close to being damaged. Partly because the bridge flattened, which should never happen, he said, and also because he estimated that the weight on the bridge was substantially higher than the standards set by AASHTO (the wordy American Association for State Highway and Transportation Officials), which he didn’t think the Golden Gate far exceeded. He said that the load already significantly intruded upon the factor of safety, and was close to completely exhausting it. But he also said that because the bridge went back to its original shape, that was a sign that it wasn’t permanently damaged.

Another engineer, who analyzed the bridge in the years after the bridgewalk, remembered that the load on the bridge was about the same as the design load. But his concept of factor of safety was a little bit different. Dipping into the factor of safety meant that the bridge would start getting damaged, but not completely fall apart. In a way, this idea is similar to the previous idea that the bridge was being close to damage, but the difference of such a simple, standard idea, was a little odd.

The current chief engineer gave me a far different answer, saying that the bridge is and was capable of being completely filled with 36 ton, 28 foot long trucks, which would be far heavier than the 1987 crowd of people. Rough calculations would put that capacity at more than 15,000 pounds per foot of bridge, more than 2.5 times the 1987 estimate. On top of that there’s an additional safety factor which would put that capacity through the roof, before the bridge would begin to get damaged. In short, the engineer said, there was no practical way to put enough weight on the bridge to get it to crack.

Now all of these experts are pretty well established– they’re either professionals who design or analyze bridges for a living, or professors at prestigious universities. What are we to do if they can’t agree on what seems to be a pretty straightforward concept?

A Field Guide for SciCom

By Meghan Rosen

Two quarters ago, David Cohn—the web whiz and crowd-funded journalism advocate who invented Spot.us—left the SciCom class of 2012 with a note-worthy nugget of internet advice.

“It’s cheaper and easier to try something,” he said, “than to debate about whether or not to try it.”

Instead of carefully considering the pros and cons of making a webpage, starting an internet-based project, or creating a social media network, his thinking goes—just do it. Instead of trying to iron out all the possible kinks before launching a new idea, figure them out on the fly. Or, in Cohn’s words, “Fail early and fail often.”

In essence, the best way to carry a new idea forward on the web is to dive in and get started. Cohn calls it “agile and iterative” development. This learn-and-go method helped him pick up new tools, develop partnerships, and nail down the ideas that eventually built the backbone of Spot.us. It even helped him generate a little pre-project buzz.

In this spirit of experimentation, I decided to do something a little different for this blog post. I decided to create another blog. A field guide, of sorts, for SciCom.

As we wrap up nine months of science-writing boot camp, I’ve been thinking about how much our class has learned over the past three quarters. We haven’t just learned how to write and report, we’ve learned how to navigate the program too.

So I wanted to create a place where future classes could come for advice: tips and tricks from the class of 2012 (and past classes too, if they want to contribute.) The platform is simple: a tumblr blog that’s open to posts from former SciCom class members (or people who know the password: scicom).

Because I want visitors to quickly find the advice they’re looking for (without scrolling through pages of past entries) I’ve included a list of tags to help group advice into categories (such as fall, winter, and spring quarters, multimedia, investigative report, etc.).  But I’m open to adding more tags, if anyone has suggestions.

I’ve also set up a questions page for new students to ask about anything that pops up during their classes and coursework. The page will forward questions to me, but I’m thinking of sending them to our class Google groups email address. This way, anyone who has the time, interest, and expertise can take a crack at answering (while letting the rest of us know who’s fielding what).

As of this posting, the SciCom Field Guide has advice from four members of this year’s class. Initially I envisioned practical tips and technical advice, but I was surprised (and a little warmed) to see that many of my classmates offered support and perspective instead of tricks of time management. So I added tags for ‘encouragement’ and ‘life.’ “Agile and iterative” in action, I suppose.

I don’t know how inspired my class will be to post to the Field Guide, but for it to work well, it will have to be a community effort (otherwise, I might overrun the blog with advice that’s specific to me—like how to pump between classes.) I also don’t know if next year’s class will look to us for help. (I, for one, would have loved to learn the clever tip about carrying business cards in your nametag at meetings. I had been stuffing my (slightly rumpled) set into a purse pocket.)

But I do know that the collective knowledge of SciCom class 2012 could potentially help students struggling with internships, class assignments, and work/life balance.

This might not but be the best way to gather and group our thoughts, but I thought I’d give it a shot. After all, it was cheap and easy.

SOD Blitz: Volunteers take on Sudden Oak Death

UC Berkeley students survey trees for sudden oak death. Photo: E. Loury

Erin Loury

by Erin Loury

Ah, the signs of spring. The sun is out, the rain has stopped (for now)—and sudden oak death is on the move. This invasive, fungus-like tree killer, which is related to the Irish potato blight, moves in fits and spurts with bouts of warm spring rains. Every spring for the past four years, scientists from UC Berkeley have mobilized hundreds of volunteers to track the disease’s whereabouts in the Bay Area.

A bay leaf showing classic signs of sudden oak death. Photo: E. Loury

This massive citizen scientist effort is called a SOD Blitz (“SOD” for sudden oak death). “It started mostly as a way to engage people,” says organizer Matteo Garbelotto, a researcher at UC Berkeley who helped identify the disease-causing water mold, Phytophthora ramorum, in 2001. Because SOD outbreaks have a cyclical nature, they fall out of the news spotlight fairly quickly.  Garbelotto wanted to keep up public interest and awareness in the disease.  “When you actually do something, you look at it differently than just sitting in the chair and listening to even the brightest researchers in the world talking about it,” he says.

I recently attended the SOD Blitz at UC Berkeley, where Garbelotto briefed about 70 volunteers in how to spot the signs of the disease and collect data. The blitzes focus on bay laurel trees, which spread the disease to oaks without succumbing themselves, the way mosquitoes transfer malaria to people. Oaks can’t pass the disease to each other, so surveying bay trees provides the clearest picture of infection risks. The symptoms are also easy to spot on bay leaves. Garbelotto instructed the participants to look for brown leaf tips, where water droplets (and the water-borne disease) would accumulate. Other classic signs include a black line and yellow halo above the tip lesion, and little black specks throughout the leaf from disease carrying water droplets.

UC Berkeley student Heather Leslie collects leaves from a bay tree that shows symptoms of sudden oak death. Photo: E. Loury

I joined a pair of UC Berkeley students surveying the bay trees on a fire road behind the campus. The girls carried a collection packet of materials in a big manila envelope. When they spotted an infected bay tree, they jotted down its GPS coordinates (with the help of an iPhone ap), collected a handful of symptomatic leaves in a small envelope, and marked the tree with flagging tape.  They also made a note of any nearby oak trees that showed symptoms of the disease – which in oaks include bleeding bar and black opportunistic fungi.

Garbelotto’s lab will test all the collected leaves for the disease agent, and create a map of infected trees.  The maps can help homeowners decide whether their oaks might be at risk, and whether they ought to take steps to treat them. “When you combine all these maps, you have a really great distribution,” Garbelotto says. “There’s no way we can do it without the volunteers.”

If you care about oak trees in Santa Cruz, there’s a SOD Blitz coming up on Saturday, May 19 at10:30am. The location is the Cal-Fire Training Room on Gushee Street (behind the forestry office at 6059 Highway 9) in Felton. For more information, contact Nadia Hamey, nadiah@big-creek.com.  And you can find out about other SOD Blitzes throughout the Bay Area.  It’s a great way to spend a few hours outdoors and do something good for science!

Look for my feature in the upcoming edition of Science Notes this summer to get the full story on sudden oak death!

Citizen scientists collect data that will help researchers track the spread of sudden oak death. Photo: E. Loury

The Lyme Twilight Zone

Beth Marie Mole

 

by Beth Marie Mole

When my mom said she was headed to the doctor for a sore knee last month, I didn’t think much of it. I figured she probably just twisted it doing yard work or something. But, when she called back to say her swollen knee was Lyme arthritis, she had my attention. And I braced myself for the dizzying world we were about to walk into.

Lyme is one of those diseases you almost can’t mention in mixed company – unless you want to pick a fight. It exists in a world where patient advocate groups distrust the medical community; where advocate-backed legislation rather than clinical evidence defines treatment options; where seemingly ordinary doctors practice “alternative” medicine; and where a long standing disease has no settled diagnostics, treatment, or even definition.

Since scientists identified it in Lyme, Connecticut in 1975, it has become the most common tick-born disease in North America. Lyme disease is endemic to the Northeast and the Pacific coast, and it’s spreading. Disease ecologists consider it a high priority emerging infectious diseases.

Yet, nearly everything else about it is hotly contested.

An adult black leg tick (deer tick)
Public domain image

Last fall, in the medical journal The Lancet, a group of doctors equated people who believe in “chronic Lyme disease” to people who deny the existence of AIDS (1). On the other side, patient advocate groups, such as the Lyme Disease Association, disagree with standard medical guidance set by the Infectious Disease Society of America (IDSA), and endorsed by the Centers for Disease Control and Prevention. Many have pushed (successfully) for laws that protect patients and doctors who believe in chronic illness and don’t follow standard treatments.

To say the least, the divide is unfortunate, says Dr. Robert Lane, a leading tick-born disease expert and epidemiologist at UC Berkeley. “I think that both sides want to get to the truth,” he says.

Part of the controversy stems from Lyme disease’s vague start. Nymph ticks the size of poppy seeds or slightly larger adults can deliver the spiral bacteria, Borrelia burgdorferi, to skin, where they mount their attack. The result might be the famous bulls-eye rash. But, advocate groups claim that as little as 30 percent of infected people will have/see this rash. While doctors who side with CDC guidelines say as much as 80 percent will have/see it. My mom didn’t even notice a tick.

After that, things get fuzzier. Early Lyme disease symptoms include fatigue, headache, fever, and depression. If you miss those super obvious signs, the bacteria invade the body, and launch late stage disease. This can fire up months to years later as fatigue, joint pain (Lyme arthritis), mental fogginess, and sometimes even heart and liver problems. For some patients, it can be a slow road to a proper diagnosis, where relationships with doctors erode along the way.

It doesn’t help that many advocate groups believe that standard tests for Lyme—ELISAs and Western blots—are wildly inaccurate. An ELISA measures the bacteria’s presence indirectly, by detecting antibodies—your immune system’s response to the infection. Advocate groups claim that immune responses fluctuate, and are unreliable. Western blots, which also detect antibodies, may miss dormant infections, they also claim. Ultimately, advocacy groups—one of the most vocal is the California based LymeDisease.org—feel that Lyme disease is under-diagnosed. Some patients with similarly vague symptoms believe they have the disease without positive diagnostics.

Members of the IDSA, which is comprised of over 9000 physicians, scientists and health care professionals, acknowledge that no test is perfect and that the ELISA test may not be accurate in the first few weeks of infection (before your immune system mounts a response). But they point to clinical data validating its use for diagnosis (2, 3). ELISAs are also a common diagnostic tool for many other infections, including West Nile virus and HIV.

However it happens, once someone is diagnosed with Lyme, the IDSA recommends (4) two weeks of an oral antibiotic, such as doxycycline or ceftriaxone, for early disease. It’s a four-week course for late stage. When my mom got her diagnosis, she immediately went on a 28-day course of doxycycline and started feeling better. But a week after she finished, she felt run down and her headaches returned.

This is where things get crazy. The IDSA would say she may just have residual symptoms, and, at most, should try another four weeks of antibiotics. Patient advocate groups say she may need antibiotics for *six months to multiple years* and that her disease could be chronic.

In multiple double blind, randomized clinical trials, long-term antibiotic therapies did not improve symptoms or the rate of recovery (5,6,7).

A deer tick on a fingernail
Copyright Stuart Meek, Creative Commons License

When I contacted the California Department of Public Health for their opinion on chronic Lyme disease, they said they had no comment.

Some doctors who believe in chronic infection support unsafe “alternative” treatments such as injections of toxic dinitrophenol, which is banned in the U.S. Such doctors call themselves Lyme Literate MDs. LLMDs are difficult to separate from infectious disease specialists who treat Lyme disease within standard protocols. In fact, to identify a LLMD, you usually have to go through patient advocate group that will give you a referral after you sign up on their website. Moreover, many LLMDs have conflicts of interest with laboratories that produce alternative tests, or have sanctions by medical licensing boards, or been in trouble with federal agencies (8,9,10). In 2008, a Kansas state court found an LLMD guilty of killing a Lyme patient with bismuth injections (11).

“[The LLMDs] are very clandestine— for good reason,” says Dr. Paul Auwaerter, a Lyme disease specialist at Johns Hopkins and the lead author on The Lancet opinion piece. At his clinic, most of the patients that come in with a chronic Lyme disease diagnoses never even had Lyme disease. Rather, they were suffering from something else, he says.

In the Northeast, where over 90 percent of Lyme disease cases are diagnosed, less than 3 percent of doctors used chronic Lyme disease as a diagnosis.

Right now, my mom is waiting for her next appointment with an infectious disease doctor (not a LLMD, I checked). She may be in the 5 percent pool of patients that need another round of antibiotics, or may just get something to treat her symptoms. Either way, she’ll get some bug spray—from me—for the next time she does yard work.

Drink at your own perceived risk

by Helen Shen

How dangerous is unpasteurized milk? Many health-conscious consumers want to know. The answer depends on how you look at the numbers.

In March, CDC scientists published a study in the journal Emerging Infectious Diseases that tried to quantify this risk by analyzing milk-related disease outbreaks from 1993 to 2006.

The research was widely covered in the mainstream news media, including in a story I wrote for the San Jose Mercury News. The study also attracted a fair amount of online outrage from many raw milk enthusiasts, who treated it as a piece of biased government propaganda.

The CDC media press release, several news stories, and the research paper itself highlighted two main points: first, that 75 percent of raw milk outbreaks occurred in states where raw milk was legal at the time (in an interview with me, first author Adam Langer called this “the most important result of the study”); and second, that raw milk is 150 times more dangerous than pasteurized milk.

Plenty of aspects of the raw milk debate are unscientific. Food choices are personal, cultural, and political. Twelve states allow retail sales of raw milk. Twenty states ban raw milk sales outright. The remaining states allow only limited raw milk sales, such as on-farm transactions.

Unfortunately, emphasizing those particular research findings may have hindered a truly scientific discussion about raw milk risks.

Photo credit: cyclonebill, Wikimedia Commons

Proving the obvious

Let’s think about the first conclusion. Between 1993 and 2006, raw milk caused more outbreaks in states where the unpasteurized product was legal. Is that like saying car accidents happen more often on roads that permit cars?

Langer told me, “It is not necessarily surprising. We do occasionally have to do scientific studies in order to prove what one would think would be obvious. But it is important evidence to show that laws that restrict the sale of unpasteurized dairy products are very important public health tools to reduce the number of outbreaks that are caused by these products.”

Basically, the study suggests that in states that ban raw milk sales, few people consume and get sick from black market raw milk, says Michele Jay-Russell, a food safety expert at UC Davis and a former scientist with the California Department of Public Health.

Hm. That’s probably good news, but it doesn’t offer any real information about how risky raw milk actually might be. That’s where the second point could help.

Outbreaks versus individuals

The authors concluded that raw milk carries 150 times greater risk than pasteurized milk of causing disease outbreaks. (A disease outbreak is a cluster of illnesses thought to originate from the same source. It could involve 2, 200, or 2,000 people.)

Here’s some of the math: Only about 1 percent of the population is thought to consume raw milk. Assuming they consume milk in roughly the same quantities as other milk drinkers, and assuming the two types of milk were equally safe, you’d expect about 1 percent of outbreaks to be related to raw milk. Instead, the CDC found 60 percent of outbreaks—150 times more than expected—were linked to raw milk.But what happens if, instead of using outbreaks, you look at those individuals involved in milk-related outbreaks? Those numbers tell a slightly different story.

In total, raw milk outbreaks sickened 1571 people. Pasteurized milk sickened 2842. So, while raw milk was implicated in 60 percent of outbreaks, it accounted for only 35 percent of all outbreak-sickened individuals. Thirty-five percent is still 55 times more than you’d expect to see from the small fraction of milk drinkers who consume unpasteurized dairy. That’s cause for concern, but it’s a much smaller effect than if you measure risk by outbreaks.

The average reader doesn’t think in terms of disease clusters, but is interested in individual risk. Health agencies, on the other hand, get concerned and become involved when outbreaks occur, says Jay-Russell.

“If you’re part of an outbreak, or if you’re the only one that got sick, it’s all the same ‘badness’ for you personally. From a public health resource standpoint, having these dozens of outbreaks, every one of those requires stopping work on other public health issues,” she said.

Milking a goat
Photo credit: Teunie from nl, Wikimedia Commons

The authors didn’t communicate the reasons for their choice—non-intuitive for the general public—for calculating outbreak statistics in their paper. Nor did they include the relative risk statistics for individuals. Doing so could have helped their case.

But because the omitted statistics would have produced a weaker result, the authors invited criticisms of manipulating the numbers to their advantage.

In a press release entitled “CDC Cherry Picks Data to Make Case Against Raw Milk,” the pro-milk non-profit Weston A. Price Foundation said, “Perhaps most troubling is the authors’ decision to focus on outbreaks rather than illnesses… In addressing the risk posed for individuals who consume a food, the logical data to examine is the number of illnesses, not the number of outbreaks.”

Distracting from the data

Jay-Russell says she’s more concerned that young people and children are disproportionately sickened by raw milk—a finding that received relatively less attention. The CDC study found that 60 percent of individuals sickened by raw milk outbreaks were younger than 20. That number contrasts with 23 percent for pasteurized milk outbreaks.

Even though a small fraction of the population drinks raw milk, the majority of those sickened in raw milk outbreaks are young. This effect is partly explained by the fact that raw milk is touted by its fans as a health food—not just acceptable for children, but especially beneficial to their growth and well-being.

In my next blog post, I’ll examine some of these health claims.

What zombie snails and teenage mutant frogs tell us about ecosystems

Beth Marie Mole

by Beth Marie Mole

The first mutant frog the kids found probably seemed like a sad fluke. The poor Northern Leopard Frog had one normal hind leg and one frail, fleshless one. But, then the class, which was out on a nature walk in 1995, found another misshapen frog—this one with only one leg—then limped another, and another. Half of the frogs in the southern Minnesota pond were mutants.

The frogs got national news coverage after that and scientists added the pond to the list of mutant hotspots. It was a growing list amid dwindling amphibian populations. Reports of creepy croakers came in from all across the West and Midwest during the mid-90s, and speculation of the cause ranged from pesticides to UV radiation.

Spidey, the Pacific chorus frog (Pseudacris regilla) that has extra hind limbs due to infection with a trematode parasite (Ribeiroia ondatrae, left).
Photo courtesy of D. Herasimtschuk & P. Johnson

Despite the high profile, ecological mystery, it wasn’t until 2010 that I learned about the disfigured frogs. It was during my first visit to Mendocino county where I met Dan Preston, a disease ecology graduate student from the University of Colorado, Boulder, who was there studying the freaky frogs.

Back in Boulder—where he has an eight-legged Pacific Chorus frog named “Spidey”—he works with ecologist Pieter Johnson, who was one of the scientific detectives that solved the mystery.

A year after the Minnesota pond hit news stands, Johnson hopped to another hotspot for misshapen frogs, Santa Clara County, to study 30 ponds. He and his colleagues discovered that afflicted amphibians were always in ponds that also had snails, which happen to be the first host of a vicious parasite – a tiny, flatworm trematode in the genus Ribeiroia.

Flatworm eggs hatch in water and make their way inside certain freshwater snails, such as the Ramshorn snail. Then, they take over. They feed on the snail’s reproductive tract – castrating their victims – and turning them into parasite factories. A month or so later, the more mature worms abandon their zombie snail-homes and set their sites on fish or amphibians. When they invade frogs, the Ribeiroia trematodes settle in the hind limbs—a telltale location.

“I’ve seen some frogs with 20 or so “limb-like appendages” coming off the back end,” Preston says.

Back in the lab, Johnson and his colleagues found that tadpoles swimming in trematode-infested waters developed the same deformities seen in the ponds. But even now, nobody is sure exactly how the trematodes botch leg development.

“There are two lines of thought: that it causes a mechanical disturbance of cells around the limb bud leading to development problems, or that it secretes some type of chemical compound that triggers haywire cell development,” Preston says. “Personally, I think it’s more of a mechanical thing than a biochemical process.”

Regardless of the means, the resulting gimpy frogs probably help the trematodes complete their nefarious plot; the limping croakers are easy targets for predators like birds and mammals – the trematode’s final host. Inside, say a bird, the trematode happily spews eggs into the bird’s feces, which could land back near a pond for the cycle to start again.

A California red-legged frog with an extra hind foot. This species is listed on the
endangered species act. Photo courtesy of D. Preston

Although the mystery might be at rest, the plight of mutant amphibians has only raised more questions, such as “Is this new?” and, “Is it getting worse?” Though Johnson and his colleagues have pieced together historical records of unusual amphibians—some dating back 200 years— it’s tricky to say if amphibian malformations caused by tretmatodes are new. But from what they can tell, they do seem to be increasing.

The boom in buggered pond-life has led Johnson and Preston to start dissecting how the trematode is triumphant and what it might mean for the rest the pond and beyond. At Hopland, Preston was trying to understand how changes in snails matter. After all, they are the first host and their populations might increase with nutrient pollution from urban and agricultural runoff. When I met him in 2009, he had set up rows and rows of black, plastic mini-pools, the size of small bathtubs, in a field at University of California’s Hopland Research station. In each mock pond, he had different types of snail communities, some with just the snails that could become zombie, parasite-factories, and others that had a mix of snails, some resistant to the wicked worms.

He and Johnson just published the results in the journal Ecology, which show that if snail populations were whittled down to just the susceptible species—low biodiversity—the trematode was in welcoming waters. When they compared their results to 320 ponds around California with snail and trematode populations, they found that the snail communities in natural ponds mirrored those in the experiment, suggesting that snail diversity might be able to reduce amphibian deformities.

But snail populations aren’t the only link to leggy hoppers. Johnson and Preston are also looking into how sitting-duck frogs change the pond’s food web and colleagues are examining the impacts of global warming on trematode populations.

In the meantime, amphibian populations are still sinking and malformed frogs have bleak outlooks. Spidey, however, is doing just fine.

Starry Starry Night: A visit to Lick Observatory

by Tanya Lewis

San Jose is a bustling city of just under a million inhabitants. Yet only 25 miles to its east, on the tranquil summit of Mount Hamilton, astronomers cast their view skyward at the Lick Observatory. I visited the observatory, which is operated by the University of California, last week.

Lick Observatory Visitor Center (Photo: Tanya Lewis)

Lick actually encompasses nine different research telescopes. The observatory was funded at the bequest of James Lick, a wealthy piano maker and land baron, in the 1880s. Lick himself was quite a character. The richest man in California at the time, he originally planned to use his money to build a giant pyramid in San Francisco in his own honor, but luckily for science, George Davidson of the California Academy of Sciences persuaded him to build an observatory instead.

The road to the observatory follows a torturous, winding route, which at times was enough to make me carsick even as the driver. After an hour of careful wending, I arrived at the summit just before sunset. One of the support astronomers met me there, and showed me around the 36-inch (1 meter) James Lick Telescope. It was the world’s largest refracting telescope when it was built in 1888, and resembles the stereotypical long-objective of an amateur telescope, though much larger. On a slightly eerie note, James Lick is buried beneath the telescope.

The 36" James Lick Refracting Telescope. (Photo: Tanya Lewis)

But not much science goes on at the Refractor these days. The night I visited, astronomers were observing at the largest telescope at Lick, the 120-inch (3 meter) Shane telescope. Unlike the 36-inch, the Shane is a reflecting telescope, like the Keck Telescopes in Hawaii. I got to go inside the dome of the Shane and watch as the telescope and shutter rotated into position. They made a sound like the Titanic scraping against un-oiled hinges.

Next I visited the observing room, where the telescope operator and astronomer(s) were. (Actually, most of the observing these days takes place remotely, at UC campuses, but that night, an astronomy graduate student was being trained on-site.) Amazingly, only one, fairly dinky-looking computer is needed to control the telescope itself. The operator collaborates with the astronomer to aim the telescope at the parts of the sky that are of interest.

The 120" Shane Reflecting Telescope (Photo: Tanya Lewis)

That night, the science agenda involved looking at distant galaxy centers, or quasars, and taking light spectra – a breakdown of light by its component wavelengths. The spectra provide information about the ionized gas in the space between galaxies, known as the intergalactic medium, which yields clues about the physics of the early universe.

Although I couldn’t stay for the whole night of observing, I set off home safe in the knowledge that, in the still Mount Hamilton night, someone was probing our galactic origins.

Blue Marbles and Ocean Microbes: A Sea Change at TEDxMonterey

Erin Loury

by Erin Loury

A volunteer placed a translucent, blue marble in my hand as I walked through the door.  Everyone else in the darkened auditorium held a similar token.  Ocean-philes of one kind or another, we were gathering at the Monterey Institute of International Studies for the third TEDxMonterey.  A community-organized event modeled after the popular TED talk series, the day’s line-up of inspiring presentations revolved around the topic of “Sea Change,” and explored the connection between people and the ocean.

My blue marble from TEDxMonterey

The blue marbles were part of a project started by Wallace J. Nichols, one of the day’s speakers. The marble represents how the Earth looks from space, a blue sphere colored by its predominant feature, our ocean. It also represents a drop of seawater, teaming with life. Nichols hopes the blue marbles will pass through the hands of everyone on the planet. When you see someone doing something to help the ocean, give a blue marble to them, and tell them to pass it on, Nichols said.  He hopes the act will help inspire gratitude for the life-giving gifts of the ocean, and efforts to protect it.

James Cameron recently took his blue marble to the bottom of the Marianas Trench before giving it away, Nichols said. I read about these marbles making their rounds at the Copenhagen climate meeting in 2009; now I’m excited to have one of my own.  I will have to think of some great ocean adventure to take my marble on before I find just the right person to pass it off to.

TEDxMonterey included a number of ocean visionaries, and contained references to Shakespeare (who coined the term “sea change” in his play The Tempest), algal biofuels, education, fishing, and talk by long distance swimmer Lynne Cox that I found particular inspiring—she broke the record for swimming the English Channel at age 15, swam across the Bering Strait, and swam over a mile in Antarctic waters with just a bathing suit, cap and goggles, to name just a few of her feats!

There was a good deal of science mixed in throughout the day, and I thought one of the most engaging scientist speakers was Melissa Garren, a researcher from MIT.  Garren called for a little recognition for the ocean’s tiniest residents: its bacteria and viruses.  She gave a nod to Prochlorococcus, a species of cyanobacteria that, along with other microalgae, produce half of the oxygen on Earth. Take two breaths, Garren said. For the first, thank the trees and macroalgae, like kelp. For the second breath, thank the microbes. Though they support our very existence, scientists only discovered Prochlorococcus in 1988. We have so much to still learn about the ocean.

Thank marine microalgae like these for half the air we breathe (photo: Daniel Vaulot, CNRS, Station Biologique de Roscoff)

Garren called microbes “the invisible engineers that control the chemistry of the ocean.” They influence how the sea feels, smells, tastes and looks. Two gallons of seawater contain more bacteria than there are people on the planet, Garren said. The audience of ocean enthusiasts collectively squirmed as we recalled how many mouthfuls of seawater we had each swallowed. When we pollute the ocean with too many nutrients, which fish farms often do, the bacteria populations can sky rocket.  When the microbe population is out of whack, the ocean experiences some nasty side effects, like a person who suffers the wrath of intestinal microbes, Garren said.

Sometimes corals are the collateral damage. Corals have a protective layer of bacteria that coats their skin of symbiotic algae, but bacterial diseases also plague them.  Garren recently discovered that the bacterial pathogen behind a widespread coral disease can actively “sniff out” traces of coral mucous on a microscope slide. It was a bit mindboggling to think of tiny marine bacteria hunting down their prey. The things scientists are discovering about the ocean constantly amaze me.

TEDxMonterey was a stimulating and inspiring event. I’ll leave you with the quote from Ariel’s Song in William Shakespeare’s The Tempest, which made it into one of the day’s talks. I just love the words—they give me chills every time I read them.

Full fathom five thy father lies;

Of his bones are coral made;
Those are pearls that were his eyes:
Nothing of him that doth fade,
But doth suffer a sea-change

Into something rich and strange.

Oh, and one shameless plug. I’m very proud of a certain photographer who was featured as a local artist at TEDxMonterey for his stunning underwater photography. Check out his work here: http://scottgabara.tumblr.com/

Marine science graduate student and underwater photographer Scott Gabara shows off his photos and camera setup at TEDxMonterey

Keep (the) Santa Cruz (Sandhills) Weird

Sarah Jane Keller

I’ve heard that Santa Cruz might be weird. I live in the redwoods above the city and maybe it’s a little strange here too. Sunset Magazine called Boulder Creek, just up the road, “absurdly rural.” In a search for the absurd, I considered visiting the nearby Bigfoot Museum to see if I could scare up a Sasquatch but turned instead to the park in my backyard, Quail Hollow Ranch County Park.

Since first visited the park, I’ve been intrigued by signs along the trail that say ” Sensitive Area Closed”. What are they hiding back there, behind the big shadowy arms of the live oaks?

Entering forbidden territory. Photo by SJK

This weekend, I found out. The Fish and Wildlife Service owns the property and there’s a good reason we can’t just go tramping around on it—and it has nothing to do with protecting Bigfoot’s habitat. Behind the signs is rare ecosystem harboring the true weirdos of Santa Cruz County: four plant species, a grasshopper, a beetle and a kangaroo rat that live nowhere else in the world.

A cage protects this federally endangered Santa Cruz Wallflower (Erysimum teretifolium), found only in the Santa Cruz sandhills and nowhere else, from hungry deer. The plants live for two or three years, but only produce flowers once. If the flowers are chomped off, the plant misses out on reproducing. Photo by SJK.

The Santa Cruz sandhills are so fragile that only 60 people are allowed to visit this particular parcel each year, 15 at a time, during Sundays in April. The perilously rare plants that grow there thrive in sandy soil free of competition from other species. And they grow right in the middle of the trail. If you walk on the trail you inevitably STEP ON A FEDERALLY ENDANGERED SPECIES. During last Sunday’s tour I was caught between the perverse thrill of having permission to accidentally trammel rare plants and the horror of doing so.

At the

beginning of the walk, our guide Shane, a systems engineer with a passion for geology and botany, pulled out some fossils to demonstrate the origins of the mountaintop beach in our backyard. He presented us with sand dollars, which are found in the 15 million-year-old silica soils only a short distance from redwood forests.

The coarse texture of the sand and the way nutrients and water slip through it fostered the evolution of the rare collection of heat, sun and drought-adapted plants a

Though naturally rare, endangered and found only in the Santa Cruz sandhills, the Santa Cruz spineflower (Chorizanthe pungens var. hartwegiana) carpets the ground where it grows. Photo by SJK.

nd animals that live there today. Since the early 1900s that sand has also been attractive for many industrial uses from making bottles, and now optics and silicon wafers. There’s an active sand quarry just across the street from Quail Hollow and six have been active in the area at different times.

The sandhills habitat has been destroyed, degraded and fragmented by mining but also by residential developments like the one I live in, vineyards, orchards and recreation. During the walk, Shane credited Jodi McGraw for assembling much of what people know about the sandhills as a UC Berkeley doctoral student. Her website about the sandhills says that there were about 6,000 acres of the naturally rare ecosystem and about 60 percent remains today. However, most of that land is not protected.

Now, when I climb a hill around my house and look out on mountains carpeted with green, I see the white sandy patches peeking through and think they are some of the most special things in my absurdly rural neighborhood (though the neon lumberjack is a close second). I came expecting to be enamored by redwoods but I also found the Santa Cruz Wallflower and the Ben Lomond Spineflower. Thank goodness for the weirdos.

In California, these Ponderosa Pines usually grow above 3000 feet in the Sierra Nevadas. In Santa Cruz county they are a low elevation oddity where they survive in the sandhills.

Purple Owl's Clover (Castilleja exserta) is a grassland flower that's not rare, but it's pretty. Photo by SJK.