15 minute read
Grow an Appetite for Plastic
Reed biologists develop colonies of bacteria that can break down plastic pollution.
It’s tough, it’s cheap, and it’s every- bacteria on shards of water bottles; lost 3% of its mass. The bacteria had where. Polyethylene terephthalate most died, but some stubbornly clung eaten it. Under the microscope, the (PET) is found in running shirts, car- to life. Since PET was its only source of students saw tiny holes where the pet fibers, curtains, solar panels, ten- nutrition, she reasoned, it had to be microbes had chewed through the PET. nis balls, microwavable containers, and digesting the plastic. (See “Bio Major More remarkable still, the sucbottles—about 500 billion bottles are Breeds Microbes That Eat Plastic,” cessful sample contained five differmanufactured out of PET every year. Reed Magazine, June 2018.) ent strains of bacteria living cheek by But the very qualities that make PET Prof. Mellies was thrilled. PET jowl, with some strains breaking down so useful also make it an environmen- is notoriously nonbiodegradable. the PET into components that other tal nightmare. Its incredible durabili- Chemically, it is a polymer, consisting strains could digest, and so on. ty means that it persists for decades, of long tough strands of ethylene glycol “These bacteria are cooperating,” clogging rivers, beaches, for- and terephthalic acid mono- says Prof. Mellies. “It’s crazy, but ests, and waterways. Some 8 GO FURTHER mers, all tangled up togeth- they’re working together to degrade million tons of plastic enters Roberts C, Edwards er. These strands lend PET its the polymers.” the ocean every year, accordS, Vague M, LeónZayas R, Scheffer H, durability; they also make it The concept of microbial symbioing to a 2015 paper in Science, Chan G, Swartz NA, virtually impervious to bio- sis isn’t exactly new, but it represents fueling the infamous Pacific Mellies JL. 2020. Environmental con- logical reaction. Yet somehow a new frontier in microbiology. Ever trash vortex that is current- sortium contain- the bacteria had figured out a since 1876, when the German biololy the size of Texas. ing Pseudomonas and Bacillus spe- way to break it down. gist Robert Koch established that the
To get a handle on this gar- cies synergistically With the support of a germ Bacillus anthracis was the cause gantuan problem, researchdegrades polyethylene terephthalate grant from the National of anthrax, researchers have tended ers at Reed are recruiting an plastic. mSphere Science Foundation, Prof. to focus on isolating single organisms infinitesimal ally. 5:e01151-20. Mellies and a new crop of so as to pinpoint their properties. But
In a groundbreaking paper students delved deeper into different kinds of microorganisms are published in mSphere, the open-source the phenomenon. They began by tak- often found living together in the journal of the American Society for ing a closer look at the bacteria’s pro- environment, and there is reason Microbiology, Prof. Jay Mellies and duction of hydrolases, enzymes that to think that they can evolve in tanstudents at Reed reported on colonies bacteria (and other organisms) use to dem. Indeed, Prof. Mellies points to of bacteria that are capable of breaking digest food. a 2001 paper by researchers in Japan down PET. Remarkably, the colonies do Hydrolases are the molecular equiv- who found symbiotic colonies of bacnot consist of a single species—rath- alent of a pair of scissors, able to chop teria flourishing in wastewater. “That er, they are composed of a consortium long, complex molecules down to size was a significant paper,” he says. “I was of five different types of bacteria that so that the bacteria can absorb them. so grateful to find that.” work synergistically to consume PET PET polymers are much longer and Having established that their conand convert it into a source of energy. tougher than any food source bacte- sortium can indeed degrade PET, the
“The novelty of our work is that we ria are likely to encounter in the natural Reed team is now focused on the are using a group of bacteria to bio- environment. But bacteria are highly next step: finding ways to make the degrade PET plastic, whereas most adaptive. Under the right conditions, process more efficient. The genetic efforts to date have focused on indi- could a colony boost production of pathways underlying hydrolase providual, isolated enzymes for this pur- extra-sharp enzymes and snip through duction and PET degradation are still pose,” says Prof. Mellies. the PET? After all, those chains teem not fully understood, but with new
The genesis for the project came with high-energy molecules that bac- tools such as metagenomic sequencfrom bio major Morgan Vague ’18, teria can use as food. ing, Prof. Mellies is convinced that who studied the relationship between Working with 192 separate colo- Reed students can boost production bacteria and plastic for her thesis with nies of soil bacteria, the Reed team of enzymes that break down PET and Prof. Mellies. She dug up samples of spent painstaking months culturing hasten the bacteria’s evolution. The muck from around Galveston Bay in them on PET. The process was ago- potential upside is huge—not only for Texas to see if bacteria there might nizingly slow. But after an eight-week fighting pollution, but also for harhave evolved the ability to feed on trial, the Reed team discovered that nessing microbial symbiosis for other hydrocarbons. She tried to culture the PET in one of their samples had
problems. —CHRIS LYDGATE ’90
photo by lauren labarre
Power from the Sky
Drones have huge potential in all kinds of fields, from agriculture to disaster relief to logistics. But they face a classic dilemma—to haul bigger payloads on longer flights, they require heavier and heavier batteries, which eats into precious cargo capacity. Entrepreneur Bill Kallman ’83 of Global Energy Transmission is working on an innovative solution: recharging drones midflight. GET has developed transmitters that can power up batteries within minutes—while the drone hovers in mid-air. Kallman envisions a future where drones cruise from one transmitter to the next, extending flight times indefinitely. The technology may be new, but the underlying concept isn’t—Nikola Tesla demonstrated remote power transmission more than 100 years ago.
Polish Your Specs
Solar cells are only 21% efficient, because silicon can absorb energy only from a narrow band of the spectrum. Engineer Zach Holman ’05 and researchers at Arizona State University are working on a new type of cell based on laminating silicon with perovskite, a crystal that absorbs energy from a broader spectrum. The tandem cells boost efficiency to 26%, with major implications for the economics of solar panels. Zach is also working on selfcleaning surfaces for solar panels that repel water and dirt.
Live Wild
Mardy Murie ’23 fought to create the Arctic National Wildlife Range.
Widely regarded as the matriarch of America’s conservation movement, Margaret “Mardy” Murie lived a
devoted life close to the land. Born in 1902, Mardy Thomas grew up when Alaska truly was a frontier; mail was delivered by horse-drawn sled and people traveled by dogsled, not snowmobile. She was raised to conserve and respect this beautiful land of berries and caribou, salmon, and endless night and day. And always, she was driven by her curiosity and the understanding that there is more to be learned by listening than by talking.
Mardy came to Reed in 1919 and spent two years on campus (one of her classmates was James Beard ’24). Later she returned to Alaska and was the first woman to graduate from what is now the University of Alaska Fairbanks. She married biologist Olaus Murie and embarked on a working honeymoon of adventure on the Koyukuk River. Traveling by riverboat and, after freeze-up, dogsled, they followed the caribou to the mouth of the river at the foot of the Brooks Range. Two years later they spent a summer canoeing and banding geese on the Old Crow River in the Yukon with their newborn son, the first of many adventures raising their children in wildlands.
Mardy and Olaus danced their life across Alaska. They danced for the joy of it, for the exhilaration of sharing in this ever-giving land. As she said, “In the midst of these difficult times... you have to know how to dance.” The same love that inspired her to dance gave her the courage to protect the wilderness she called home. Mardy understood that in preserving wilderness, we preserve the best of ourselves.
The Muries organized a scientific expedition to the Sheenjek River in 1956 as a key step in their campaign to protect the northeastern part of Alaska. In 1962, Mardy published Two in the Far North, an influential memoir that generated crucial publicity. Later she testified before Congress about the importance of protecting wild spaces and planted the seed of a profound idea—to preserve an entire biome within an intact ecosystem: a vast expanse of ocean and tundra, rivers and lakes, fowl and mammals, untouched by human greed. The structural change she fought for resulted in broad success: designation of the Arctic National Wildlife Range (now Refuge) in 1960, passage of the Wilderness Act in 1964, then the Alaska National Interest Lands Conservation Act in 1980. Oil was found at Prudhoe Bay in 1968 and this, too, kept her vigilant. She wrote several more books and was awarded the Presidential Medal of Freedom in 1998 by President Bill Clinton.
Mardy wanted her great-grandchildren to be able to stand on the tundra and witness the same land she so loved. She fought tirelessly for them, and for all of us, to have this legacy of wild spaces. The question Mardy asked of herself rings true today: What, after all, are the most precious things in a life?
Author and naturalist Mardy Murie fought for key legislation to protect wild spaces. Here she is in Bettles, Alaska, 1924.
—HEATHER MACFARLANE ’15
photo by molly matalon, mit technology review, courtesy of ucdavis
Make Better Rice
For billions of people around the globe, this gene into Swarna, a variety of rice rice is life. But rice is also exquisite- popular with farmers in India and ly vulnerable to flooding. Submerge Bangladesh. The results were astonrice plants under water for more than ishing. The Swarna-Sub1 can withthree days and they drown. stand prolonged submersion and
As the planet gets warmer, this prob- yields more grain than conventional lem is bound to get worse, varieties. With the help of especially as Himalayan glaIn India, Indonesia, and Bangladesh, the Gates Foundation, Sub1 ciers melt and flood the river floods destroy as rice has now been distributdeltas of South and Southeast much as 4 million tons of rice— ed to 4.9 million farmers and Asia. Plant geneticist Pamela enough to feed 30 is being raised on 5 million Ronald ’82 and colleagues million people— every single year. acres in seven nations. Sub1 at UC Davis began to look at is particularly beneficial to Dhalputtia, an obscure strain of wild the very poorest farmers, since they rice shunned by farmers because of typically occupy the cropland that is its poor yield and unpleasant texture. most vulnerable to flooding. Pamela is Dhalputtia has one remarkable proper- a Fulbright fellow, a Guggenheim fellow, ty, however: it can withstand prolonged and was named by Scientific American flooding. After years of painstaking as one of the world’s 100 most influwork, Pamela and her team isolated ential people in biotechnology. She is Sub1, the gene responsible for flood also the author of Tomorrow’s Table (see tolerance, and successfully introduced page 27).
Rethink Your Values
What is the value of a forest? What is the worth of wilderness? Economists from Adam Smith onwards thought of forests as vertical lumberyards—their value was defined by the timber that could be harvested from them. Then in 1967 came a landmark paper by John Krutilla ’49 that fundamentally altered the way economists think about wilderness by setting out a framework for calculating its value as a natural resource to be preserved, rather than a feedstock to be consumed.
“John Krutilla can fairly be said to have created or stimulated most of the agenda of modern environmental economics,” said Nobel laureate Kenneth Arrow. “He pioneered in developing the idea later called ‘existence value,’ the value generated by the mere existence of an amenity, such as an unspoiled wilderness or species of animal or plants.”
A few years later, Lester Lave ’60 did the same thing with air pollution. Until then, smog was considered an aesthetic issue—an unfortunate but inevitable industrial byproduct. Lester rethought the cost of pollution and found a way to quantify it. By showing how pollution in American cities was linked to an increase in death rates, he created the intellectual framework for environmental regulation. Writing in the New York Times, economists David Keith, Jay Apt, and Joule Bergerson hailed this as “a major advance at the junction of epidemiology, atmospheric chemistry and public policy.”
This HOLC map of Elizabeth, NJ, from 1939, shows neighborhoods graded by perceived lending risk (as judged by quality of housing stock and race and ethnicity of the residents). Green areas were graded the safest, followed by blue, yellow , and red (hence the term redlining.)
Race, Heat, and Redlining
Urban heat islands are often a legacy of racism. Cate Mingoya ’08 has ideas on how to fix that.
Global warming doesn’t affect everyone the same way, especially in big cities. Some neighborhoods are far more vulnerable to extreme heat than others. Lower elevation makes them vulnerable to flooding. More pavement soaks up sunlight during the day and radiates heat like a furnace at night. Fewer trees mean less shade. During a heat wave these areas, known as urban heat islands, heat up faster and stay hot longer. In some cities, the temperature in a heat island may be as much as 20 degrees Fahrenheit hotter than in other parts of the city, with devastating consequences for residents, who are often more likely to belong to marginalized communities.
As you might suspect, this is no accident.
No one understands this better than Cate Mingoya ’08. As director of capacity building for the nonprofit Groundwork USA, she leads an initiative dubbed Climate Safe Neighborhoods. Using satellite technology from NASA and NOAA, her team has compiled detailed maps of dozens of cities around the nation that track a host of variables such as temperature,
tree cover, impermeable surfaces, and propensity for flooding.
But the most striking thing about the maps is how closely they line up with maps made almost 100 years ago—the infamous “redlining” maps drawn up in the 1930s by the federal Home Owners’ Loan Corporation that perpetuated segregation for decades. On the HOLC maps, greenlined neighborhoods had top-quality houses and their residents were overwhelmingly white. Redlined neighborhoods had poorer quality homes and were populated by residents of color. (HOLC refused to back loans in redlined neighborhoods—often the only places where people of color were allowed to live— creating a vicious cycle.)
Set the HOLC maps and the climate maps side by side, and see for yourself.
In Denver, Colorado, for example, the average summer temperature in the greenlined neighborhoods is 95° F. In the redlined neighborhoods, it’s 102° F. Impervious surfaces make up 28% of the greenlined neighborhoods but 60% of the redlined neighborhoods. Tree canopy covers 21% of the greenlined
MEDIAN LAND SURFACE TEMP (F): 72 111
This map shows the summer temperature in Elizabeth more than 75 years later. Data was calculated using Landsat 8 imagery on summer days (June, July, and August) between 2016 and 2018 with less than 10% cloud cover. The mean surface temperature for formerly redlined neighborhoods is 3.5° F hotter than the greenlined neighborhoods.
neighborhoods but only 4% of the redlined neighborhoods. And the pattern is repeated in city after city, more than 70 years after the maps were drawn up.
Of five cities in the study, the temperature in the redlined neighborhoods was 5 degrees hotter. They had 20% more impervious surfaces. And only a third as many trees.
Cate grew up in Queens, New York, in a neighborhood where “there was only one tree on the block, and every summer people used to fight for the shade.” At Reed she took courses in history from Prof. Jacqueline Dirks ’82 and religion from Prof. Kambiz GhaneaBassiri. She majored in biology and wrote her thesis on intraspecies recognition in cichlids with Prof. Suzy Renn. After Reed she did a stint with Teach for America in the Bronx, earned a degree in urban planning from MIT, and worked in public housing for the state of Massachusetts before joining Groundwork.
She began work on the project two years ago and has been heartened by its impact. “The maps have really transformed the minds of people who were skeptical of both structural racism and climate crisis,” she says. “It gives you energy and momentum to talk about changes in the future. Once you see it on the map, you can’t unsee it.”
Cate is working closely with residents in formerly redlined neighborhoods to press for change. For example, the maps showed that the Globeville neighborhood in Denver has only 1% tree canopy, compared to 23% in other neighborhoods—a figure that gave residents a concrete target to aim for. Now, thanks to neighborhood advocates, the city has promised to plant 3,000 trees in Globeville. “Our goal is to help neighborhoods become more resilient to climate crisis,” she says. “But we also want to help them build capacity to advocate for themselves in the political system.”
Formerly redlined neighborhoods have roughly a third as many trees, but Cate Mingoya and Groundwork USA are changing this.
—CHRIS LYDGATE ’90 GO FURTHER
To see more maps, check out https:// groundworkusa. org/climate-safeneighborhoods/
