The Triumph of Seeds (10 page)

Guar gum comes from a scruffy-looking cluster bean grown primarily on farms in Rajasthan, India’s, “Desert State.” Botanists put it with the
endospermic legumes
, a small group whose seeds lack the hefty cotyledons we know from beans, peanuts, and other members of the pea family. Instead, guar seeds store their energy in an endosperm loaded with highly branched carbohydrates. The diagrams in a chemistry textbook make those molecules look like maps of the London Underground, but to a baby guar plant in the Rajasthan Desert, they are a simple and essential adaptation.

“These tissues play a dual role,” Derek Bewley told me. “First, they can be broken down into food, the glucose that fuels plant growth. But they also provide a protective, moist layer surrounding the embryo.” He explained how the branched molecules inside a guar seed have an incredible ability to grab water and hold on tight. For a desert plant like guar, this trick transforms every rare cloudburst into a vital germination opportunity. It’s a habit that has evolved several
times—locust beans can do it, and so can fenugreek—but always in places where the climate is dry.

Rajasthani farmers have grown guar for thousands of years, using it as a fodder for livestock and occasionally cooking up the green pods as a vegetable. But their fortunes began to change when people realized that guar-seed gum makes a palatable thickener
eight times as effective as starch. Extracted and purified, guar gum soon found its way into everything from my Almond Joy ice cream to ketchup, yogurt, and instant oatmeal. By the year 2000, India’s guar exports to the food industry topped $280 million, but that was nothing compared to the boom that lay ahead.

The term
fracking
refers to an oil and natural gas extraction process known in the industry by its full name, hydraulic fracturing. It involves drilling boreholes deep into bedrock and using pressurized fluids to break apart and hold open gas-rich seams. When the fracked well is pumped out, the valuable hydrocarbons come along for the ride. Over the past decade, this once-obscure technology has grown into a multibillion-dollar global enterprise, opening up vast new deposits of shale gas and coal-bed methane. Economists expect it to effectively end North American reliance on foreign oil, fundamentally altering the world energy market. Drillers in the United States alone now frack an estimated 35,000 wells annually. And into each one of those wells they pump several million gallons of fracking fluid, a goopy combination of water, sand, acid, and chemicals all held together by one thing: guar gum.

In Rajasthan, the wholesale price for guar has risen by more than 1,500 percent in just a few years, sometimes doubling on a weekly basis. Subsistence farmers who once fed the stuff to their cows suddenly found they could sell it for enough to buy a television, then a motorcycle. Now, many are building new houses or taking family vacations abroad. Shortages of beans in 2011 and 2012 caused several drilling operations in North America to shut down, and the stock price of oil giant Halliburton Corporation fell by nearly 10 percent the week it warned shareholders that guar prices now accounted for
nearly a third of its fracking costs and would “impact the company’s second quarter margins more than anticipated.” Tight supplies and the soaring price tag have forced many in the food industry to look elsewhere for thickeners. Not surprisingly, they’re finding alternatives in the seeds of other dry-country “endospermic” beans, including carob (from a Mediterranean locust tree), tara (from a coastal Peruvian shrub), and cassia (from the Chinese sicklepod). The fortunes of all three species—and their growers—are expected to surge on the coattails of the guar boom.

It’s doubtful that any oracle could have foreseen the great fortunes waiting to be made from grinding up guar seeds and pumping them underground. Indian crop reports as late as 2007 do not even list hydraulic fracturing as a potential market. The guar story shows how innovations in the evolution of seeds can drive innovations in their use. From a guar bean’s ability to retain water, we derive an industrial thickener, and suddenly seed energy is being used to extract fossil energy. For the oil industry, it represents something of a homecoming, since one of the most productive fracking sites in the world lies in the state of Pennsylvania, where the first commercially successful oil well was drilled in 1859. For seeds, drilling beneath Pennsylvania’s hilly countryside marks a far more ancient return.

If the goal of hydraulic fracturing were fossils instead of hydrocarbons, the wells tapping Pennsylvania’s Marcellus Shale would spout geysers of tiny snails and clamshells. They would not, however, produce a single seed. Because not only did those rocks form in a seabed devoid of plant life, they come from a time millions of years before seeds even evolved. Like any other new adaptation, seeds began as an oddity, bit players in a much larger drama. They appeared in the first years of the Carboniferous Period (360–286 million years ago), a time when most plants reproduced by spores. We know those spore plants best for what they left behind: vast swamp forests that fossilized as a shiny, black rock called coal. In Pennsylvania, coal deposits lie in the younger rocks directly on top of the shale, forming a layer so thick that it helped to fuel America’s Industrial Revolution and
inspired geologists to name an entire period
“the Pennsylvanian” in its honor. To glimpse the evolution of seeds, a fracker would simply need to drill shallower wells and start poking through the tailings.

Miners have always known they lived in a world of fossils, but scientists are starting to catch on, too. Recently, teams of paleobotanists—experts in fossil plants—have begun exploring and mapping old mine shafts, redefining our understanding of how and where seeds evolved. They’ve realized that the best way to understand a Carboniferous ecosystem is to walk through one, and the only place to do that is in a coal mine.

Seeds Unite

Scientific principles and laws do not lie on the surface of nature. They are hidden, and must be wrested from nature by an active and elaborate technique of inquiry.

—John Dewey,

Reconstruction in Philosophy
(1920)

CHAPTER FOUR

What the Spike Moss Knows

The enormous quantity of vegetable debris necessary for the formation of even a single coal bed has led to the belief that the vegetation of Carboniferous times was ranker and more luxuriant than at any other time in the earth’s history, and that it grew in enormous swamps under torrid cloudy climate conditions.

—Edward Wilbur Berry,
Paleobotany
(1920)

“I
t’s going to be pretty much impossible to get you into a coal mine,” said Bill DiMichele, telling me precisely what I did not want to hear. “Coal companies have been stigmatized by the double whammy of safety regulations and getting the blame for global warming,” he explained. They didn’t welcome new faces on his team, particularly not nosey, book-writing biologists.

This dashed my hopes of strolling through a Carboniferous forest, but I couldn’t exactly second-guess Bill’s judgment. As the curator of fossil plants for the Smithsonian, he’d been leading coal-mine expeditions for years. Together with colleagues from various universities and government agencies, Bill had discovered an ancient river valley
in Illinois, 100 miles long, where every detail of the forest was beautifully preserved in the rocky ceiling of the mine. “We simply look up and map the plants,” he told me. “See what was growing where.” He made it sound easy, but the forest emerging from those maps was anything but simple. In fact, it was redefining the whole context of seed evolution. The good news for me, he went on, was that there were plenty of places to see some of the same fossils on the surface. “Tell me what you have in mind,” he said, “and I’ll ask around.”

S
ix months later, I stood next to Bill at the bottom of a desert canyon, watching dozens of paleontologists from around the world scramble up the slope toward a dark seam in the rock. “This is only a coal bed to someone from New Mexico,” he said with a smile. But while it couldn’t match his Illinois mine in scale, the thin vein exposed on the wall above was otherwise remarkably similar: the carbonized remains of an ancient swamp forest, with beautiful examples of its plant life preserved in the surrounding rocks.

Soon the canyon echoed with hammers ringing on stone as people reached the coal and dug in. It was the first day of a conference devoted to what paleontologists call the Carboniferous/Permian Transition, a critical time in earth’s history when the climate abruptly changed from hot and humid to dry and variable. Traditionally, experts considered this a moment of triumph for seeds. The giant horsetails and other spore plants that dominated Carboniferous swamps relied on a warm, wet environment. They couldn’t adapt to the changing climate of the Permian, giving seed plants the opportunity to proliferate, overcome the spore plants, and dominate the global flora. It’s a nice story, but to Bill and a growing number of other specialists, there’s just one problem: it’s dead wrong. No one denies that spore plants declined in the Permian, but the real triumph of seeds probably came much, much earlier.

“I used to go to the field expecting certain things,” he told me, explaining how textbook knowledge can burden the mind with preconceived notions. “Now I go to the field looking. I’ve found it’s
more productive to just dig a hole and see what I find.” In thirty years as a Smithsonian paleontologist, Bill DiMichele has dug a lot of holes. Compact and fit in his khaki vest and baseball cap, he moved around the dig site in New Mexico with the efficiency of experience, rarely swinging a hammer, but always there to comment on a new find. “You guys are in it, man,” I heard him shout at one point. “You’re in it!” Bill maintains the enthusiasm of a much younger scientist, but after a few hours of conversation I understood what really lay behind his long career: insatiable curiosity. For every question I asked, he seemed to have dozens of his own. They came out in a torrent, full of fresh ideas designed to wash away layers of old thinking. Just like a paleontologist in the field, he makes his intellectual discoveries by moving a lot of rock.

This approach opened Bill’s eyes to the glimmer of something new in that Illinois coal mine. Most of it looked like a typical Carboniferous forest, dominated by tree-sized spore plants related to modern horsetails and club mosses. But whenever the ancient terrain climbed upward, even a little bit, he and his colleagues saw more fossil seed plants. And when they encountered a side channel filled with debris from further up the slope, it was a jumble of conifers. No one doubts the dominance of spore plants in coal forests, but only a minor part of the Carboniferous landscape was swampy. What was growing in the uplands, on the hillsides, in the mountains?

“Hey Bill!” someone called, and motioned us over to a slab of rock at the base of the slope. There, etched in stone, was a good summary of the story I’d come to New Mexico to see. “Nice one, Scott,” Bill said, as he leaned in for a closer look. (Though people had come to the conference from as far afield as China, Russia, Brazil, Uruguay, and the Czech Republic, the world of Carboniferous/Permian specialists is a small one, and they all seemed to be on a first-name basis.) The rock had split neatly down the center, revealing mirror images of two plant stems lying side by side—a giant horsetail in the genus
Calamites
, and an early seed-bearer called a
pteridosperm
, or “seed fern.” The calamites stood out in sharp relief, its dark ridges
and grooves like a scaled-up stalk of any modern horsetail. The seed fern’s trunk looked like lizard skin, scaly black and orange against the tan surface of the rock. Both species were long extinct, but for me, seeing them together embodied that ancient struggle between spores and seeds.

F
IGURE
4.1.  These fossils from a New Mexico coal bed sum up the ancient struggle between spores and seeds. They show the stem of a giant horsetail named
Calamites
right alongside that of an early seed fern. The plants grew side by side in the great wetland forests of the Carboniferous. P
HOTO
© 2013
BY
T
HOR
H
ANSON
.