When I arrived in St. Louis a couple of months later, Pakrasi told me that he’d been fascinated by photosynthesis his whole life. “Every plant is a fantastic power reactor,” he explained. “Let’s learn from nature how to do that ourselves. Let’s have a perpetual synthetic plant that makes energy.” He and his colleagues at I-CARES are convinced humans could be using algae to fuel our cities in a century. The cornfields outside Pakrasi’s office window would bloom with photosynthetic antennae, or superefficient solar cells atop flexible structures, their light-consuming faces twisting to follow the path of the sun across the sky. Energy breweries the size of local beer megacorp Anheuser-Busch would be packed with vats full of bubbling blue-green algae that could be used in batteries or other chemical processes. Humanity would survive the fossil-fuel age by drawing energy from cyano. But before Pakrasi’s visions can come to pass, scientists need to figure out how photosynthesis works.
In his lab at Washington University in St. Louis, researcher Himadri Pakrasi shows another researcher some of the cyanobacteria colonies that have been engineered to produce higher amounts of hydrogen. (illustration credit ill.8)
Despite what you may have learned in high school biology, photosynthesis isn’t simple. In fact, it’s a chemical process that follows some seriously weird and mysterious pathways—some of which we still don’t understand. Another Washington University professor, the physicist Cynthia Lo, flipped her laptop open to show me her work on photosynthesis, glanced at some diagrams, and looked momentarily exasperated. “You know why most plants are green?” she asked rhetorically. “It’s because they’re terrible at capturing and absorbing green light. So they capture blue light, but they reflect green. And that’s what you’re seeing in this bright green algae.” Lo is one of Pakrasi’s research collaborators at I-CARES, and the principal investigator on the Photosynthetic Antenna Project. She’s working out the basic science that might one day lead to Pakrasi’s vision of superefficient solar cells collecting light to power the city of St. Louis. Lo clicked through some diagrams of how photosynthesis works at the atomic level, photons colliding with molecules called pigments to produce energy.
Then Lo returned to a theme that would come up a lot in our conversation: cyano are actually terrible at reaping the benefits of photosynthesis. Not only are they missing out on green light, but they only convert about 3 percent of the light they harvest into energy. By comparison, commercially available solar cells convert about 10 to 20 percent of incoming light into electricity. But, Lo said, today’s solar cells can only harvest a small percentage of the light wavelengths that cyano collect—so the bacteria are still way ahead of us in that department. But not for long, if Lo and her lab have anything to say about it.
Lo’s research into the physics behind light capture could help engineers build solar cells that replicate the molecular smashup we see during photosynthesis. Engineers call this biomimesis, or the practice of imitating biological forms to make artificial systems work as efficiently as living systems do—or more efficiently. “A biological system is intriguing because nature has optimized it,” Lo explained. But it’s not optimized enough. Algae harvests light really efficiently, but doesn’t convert it into energy efficiently. Solar cells are efficient at making energy but not at light harvesting. Ultimately, Lo’s goal is to figure out what it would take to develop what she calls a biohybrid solar cell that combines the light-capturing abilities of cyano with the energy-conversion abilities of existing solar-energy technology.
By trying to copy the energy reactors inside each cyano cell, Lo and her team are learning the best possible lesson they can from this mega survivor. They are trying to diversify our energy supply, creating new ways for us to gain energy from the environment so that we can survive long-term with a sustainable electrical grid. It may be decades before we crack the code on photosynthesis, but this ancient organism could guarantee a better future for the planet—just the way it did billions of years ago.
Turning Coal Plants into Cyano Breweries
Another of Pakrasi’s collaborators is working on a strategy to take us from a world run by coal to one powered by plants. Environmental engineer Richard Axelbaum, a wiry man whose office desk is decorated with angular chunks of coal, is interested in the near future of alternative energy. Pakrasi and Lo are looking perhaps half a century ahead, while Axelbaum looks just 10 to 20 years out. He has to be a pragmatist. That’s why he works on “cleaner coal” technology and carbon sequestration, the practice of sustainably disposing of coal’s greenhouse gas by-products.
One of his projects is a prototype coal-combustion facility called the Advanced Coal and Energy Research Facility, located in a huge, high-ceilinged warehouse on the Washington University campus. The facility sustains tanks of healthy algae using a by-product of coal processing. From a viewing gallery two floors above, Axelbaum showed me a tangle of thick pipes, cylindrical tanks, and a grid of shelves packed full of bubbling aquariums. Axelbaum pointed to a tank that looks like an outsized metal barrel turned on its side. “That’s the coal-combustion chamber,” he explained. Unlike typical coal-burning plants, this chamber burns the coal in a pure oxygen environment. As a result, the only by-products of the process are “cleaner” because they’re composed almost entirely of carbon dioxide and ash, with no nitrogen compounds mixed in. “Every generation has had its clean coal,” Axelbaum remarked. Early twentieth-century facilities improved on the extremely dirty coal-burning practices of the nineteenth century, for example. And now he’s hoping that we can improve the process even more, bringing us one step closer to truly clean energy.
Axelbaum’s finger followed a thick duct emerging from the combustion chamber. “That goes to a white-ash capture chamber,” he said, identifying a big, rectangular bin. Normally, coal ash is stored in large open-air ponds, which can cause environmental damage. “Our hope is that all this ash can be put to use, whether in concrete or new kinds of conductive materials,” Axelbaum said. As for the carbon dioxide? “That’s going over to the algae tanks.” Axelbaum pointed at pipes leading to the aquariums. The algae absorb the carbon, thriving on the gas. Axelbaum’s oxy-coal combustion could be feeding (literally) the next generation of superclean energy production.
The Algae Economy
A couple of years before I visited Pakrasi, his team made an incredible breakthrough. They were working with a mutant strain of cyano that releases hydrogen instead of oxygen during photosynthesis, and they managed to coax the algae to produce ten times more hydrogen than other strains had. Hydrogen is often called a clean fuel because when it’s burned it releases mostly water. Hydrogen fuel has been used for rockets, but its production is too expensive for consumer markets. Still, its widespread use in every home is part of the future of cyano-powered energy that Pakrasi, Lo, and Axelbaum dream about.
Imagine a world where brewers grow hydrogen fuel by feeding cyano with the carbon dioxide released from burning coal. The Pakrasi lab’s cyano also consumes glycogen, a by-product of biodiesel production. So basically, these algae cells are eating two harmful by-products of energy production to produce a form of fuel whose consumption releases almost no toxins at all. “They give you a lot of bang for your buck,” Pakrasi said with a laugh. Eventually, we could wean ourselves off coal and make the leap into a cyano-powered world full of new kinds of green fuel.
Pakrasi imagines a future where biologists could even develop specific strains of cyano to transform all aspects of industrial production. The bacteria could eventually replace petroleum, and aid in the production of chemicals like polypropylene, which is used in the synthesis of everything from rope and lab equipment to thermal underwear and durable plastic-food containers. Famed scientist and U.S. secretary of energy Steven Chu has talked about replacing the oil economy with a biofuel “glucose economy.” But Pakrasi and his colleagues in I-CARES have refined this notion even further, and speculate about a global algae economy whose engines run on photosynthesis.
Pakrasi, who
studied physics in India before coming to the States for his Ph.D. in biology, says he often looks to India and China for inspiration when he thinks about how to implement the discoveries he’s making in the lab. “It’s hard to [test new energy systems] here or in Europe because these countries have stable infrastructures that are already built. We’re always trying to catch up, to retrofit,” he mused. “But in China or India, it seems like every millisecond they are setting up new structures. These are the places where the technology we’re developing here can be applied directly.” Under Pakrasi’s guidance, I-CARES has developed strong relationships with universities in India and China, and researchers in St. Louis collaborate with colleagues across the world. They’re even reaching out beyond the sciences, to bring in experts in ethics and sociology. “As scientists, we’re good at coming up with technical solutions,” Pakrasi said, “but as far as the policy and human angles, we have to collaborate with [other branches of the university too.]”
I-CARES is the kind of institution that we’ll be seeing more often at universities and in industry, combining people from many disciplines to come up with global solutions to problems that straddle the line between science and society. Already, the U.S. Department of Energy has funded a massive effort in California, the Joint Center for Artificial Photosynthesis, whose aims are similar to I-CARES. Its team of over a hundred scientists, many based at Caltech and the Lawrence Berkeley National Laboratory, aims to develop a way to extract clean energy from sunlight, water, and carbon, just the way plants do.
This futuristic collaborative research could one day save the world. And it grew out of the simple cyanobacteria and its best lesson, which is to adapt and diversify by taking advantage of a sustainable form of energy. In the next chapter, we’ll learn about another life-form with an extraordinary survival mechanism—one that may have helped bring it back from the brink of extinction. You might say that this animal, the gray whale, lives by memory alone.
12. REMEMBER: SWIM SOUTH
GRAY WHALES JUST look like survivors. Their slate-colored skin is crusted with barnacles, and their huge, scarred jaws curve downward in what seem to be permanent grimaces. Bottom-feeders who mostly eat tiny crustaceans, these creatures nevertheless have a reputation as formidable fighters. Only packs of orcas and humans usually dare to hunt them, and accounts going back several centuries describe the deadly wrath of grays pursued by whalers. In 1874, the whaler and naturalist Charles Melville Scammon wrote about his experiences hunting grays. He recalled, “Hardly a day passes but there is upsetting or staving of boats, the crews receiving bruises, cuts, and, in many instances, having limbs broken; and repeated accidents have happened in which men have been instantly killed, or received mortal injury.” Grays, he explained, possessed “unusual sagacity,” which made them a hard target—especially when the animals’ intelligence was coupled with their 35-to-50-foot lengths, 80,000-pound bodies, and “quick and deviating movements.”
Despite their ferocity, grays have one vulnerability. Every winter, they migrate thousands of kilometers from the safety of their Arctic Ocean feeding grounds to a series of warm lagoons in Baja California, Mexico. One of the most popular spots is nicknamed Scammon’s Lagoon, after the whaler. Theirs is close to the longest migration taken by any animal on the planet, and the whales will encounter many predators and treacherous conditions along the way. Then, after a winter spent having children (and making them) in the lagoons, they begin the trip back up the coast again, often tailed by their young. Though both the Arctic Ocean and Mexican lagoons are relatively sheltered from predators by natural barriers, the long migrations in between leave the whales exposed to danger for months at a time. How do they manage?
The gray whale travels on one of the longest migrations of any animal in the world. (illustration credit ill.9)
Grays have evolved a number of features that seem to protect them during their migrations. Remarkably, the whales never stop swimming during these journeys. Their brains “sleep” by shutting down only one hemisphere at a time, so one part of the gray’s brain is always awake to keep it moving in the right direction. Even more unbelievably, grays rarely pause to feed during their migration. Instead they live on stored energy. They’ve spent the entire summer grazing on the Arctic seafloor, building up a thick layer of energy-storing blubber which they burn through during the roughly seven-month round-trip to Mexico. Grays eat by taking giant bites of dirt and sifting tasty crustaceans out through the baleen filters in their mouths. This is why they’re often seen with big, muddy smears on their lips after they eat. Marine biologists often jokingly call them the cows of the sea. Grays spend half the year eating so that they can spend the other half migrating and reproducing.
It’s likely that grays have been living this way for the many millennia since they first evolved 2.5 million years ago. Grays are also slightly less complex than some other cetaceans, which has led some biologists to speculate that they are a more ancient species. They don’t “sing” by creating complex harmonies like humpback whales do. They emit what scientists call moaning noises that can be heard only at close range—unlike humpback songs, which can be heard for kilometers underwater. Though grays are able learners, as Scammon observed over a century ago, they don’t exhibit a lot of social behavior like their cetacean cousins the dolphins. Instead of swimming in pods, they prefer to migrate in loose, ever-changing groups of two or three. Many travel alone. Still, grays have maintained what could be called a tradition, their great migration, that gets passed from one generation to the next. This isn’t a matter of mere instinct. Scientists believe it’s something that each new generation of juveniles must learn from the adults, like passing along a map that is vital to the survival of the species. It’s therefore no exaggeration to say that grays survive by relying on their memories. Without memory, they would never find food, nor enjoy a mating season.
Humans nearly drove gray whales to extinction in the early twentieth century, but thanks to one of the earliest conservation agreements in the world, the gray population today has rebounded to what it may have been before whalers thinned the animals’ ranks. The story of gray whale survival offers us two lessons. It teaches us the importance of passing along knowledge from one generation to the next, and it shows us one sure way to stop extinction in its tracks.
Migrations and Memory
People have been observing gray whales for centuries, but there are still many aspects of these creatures’ lives that remain a mystery. Often, we only catch glimpses of their behavior when the whales are in trouble, straying from their usual paths. This was certainly the case in 1988, when an Inuit whaler spotted a group of three grays stranded in the Arctic waters. It was so late in the season that ice had blocked their path out to the northern Pacific. Grays begin their southern migration when the Arctic starts to freeze. If they stay to graze a little too long, they get boxed in by ice that’s formed over the top of the ocean. With no room for the animals to surface and breathe, the straggler grays drown. It happens to a few whales every year, and locals are used to seeing their bodies wash ashore after the ice retreats in summer. But these grays hadn’t drowned yet—in fact, all three (including a small calf) were surfacing to breathe out of a small open hole in the ice. Footage of their struggle to survive captured national attention, bringing television crews and scientists flocking to the small Alaska town where the creatures were stranded.
A young biologist named Jim Harvey came too, trying to reconcile the behavior of these grays with what he’d seen before. These three were clearly working together to share the airhole and survive, though typically grays are solitary creatures. What’s more, the grays seemed to figure out that the humans jumping up and down on the ice around their hole wanted to help them. Eventually, after forces from both the Soviet Union and the United States got involved in the quest to free the whales, the grays followed an icebreaker out to the open sea. Harvey, now a professor at Moss Landing Marine Laboratories (MLML) on Monterey Bay, has spent
the decades since the incident studying marine mammals and other creatures that make a home on the shoreline.
When I visited Harvey at MLML, a cluster of artfully designed, recycled wood buildings built just a few yards from the waters of the bay, the door and windows in his office were thrown open. Outside, seabirds skimmed over the sunny water, and grass furred the sand dunes. Further out to sea, sea lions barked and frolicked in waters where the grays travel twice a year. For decades, Monterey Bay has been a prime spot for gray whale observation—it seems to be a favorite place for the whales. Here they swim very close to shore, making it easy to take population counts and watch them in the wild.
From decades of observation, it’s become clear that the whales don’t choose just one group of companions for the whole migration. “They’ll be with a bunch of animals, forming and changing groups all the time,” Harvey told me. “It’s like being in a bicycle race. You can draft behind [the leader], and it’s nice to be in a group because the guy in front is usually paying attention. I think gray whales do that, too. They trade positions in terms of paying attention.” Harvey had just come in from a run along the water, where he’d followed a narrow trail between MLML, a few other local marine-biology labs, and the undeveloped coastline.
His mind still on the dynamics of racing, Harvey pondered a question that is hotly contested among biologists. How, exactly, do the grays learn to navigate their way along all those thousands of kilometers of coastline? “I’m purely speculating,” he said, “but I think they’re following each other, and somebody else follows them, and they remember it.” When I asked whether they’re communicating directions with sound, too, he shook his head. “I’m sure they don’t talk to each other. They’re just following each other.” Young whales always make the trip with an animal that has gone before.
Scatter, Adapt, and Remember: How Humans Will Survive a Mass Extinction Page 14