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Thursday, August 9, 2012

Extremophile Planet

The Red Planet

Like millions of other Earthlings, my heart thrilled as Curiosity made improbable contact with the surface of the Red Planet. The upright ape pries open another nut, I thought to myself. Our niche expands again.

The first photos from Mars look like turn-of-the-century pinhole camera images of an alien and exotic land. They suggest a window to a past, seen “through a shattered glass, darkly.” We are here to look for shards of the past, fragmentary glimpses of what once flourished here. Maybe Curiosity will tell us about life on Mars, and maybe Mars will tell us something about life on our own blue marble.

Mars appears blasted, utterly inhospitable. It’s easy to conclude that life made no start on this barren rock, that no spark ignited the complex dance of carbon. Life may be unique to Earth. But the more we learn about the Red Planet, the less ‘unique’ Earth seems to be. Like claims about humanity’s top rung on the four-legged hairy ladder of life, our place at the planetary table seems a little less secure. The boundary between us and them sidles ever closer.

First photos from Curiosi

Mt. Sharp : NASA
Mars has a lot in common with us, besides being a great home for our discarded electronics. Though its surface is now too cold and dry to support known life forms, it was once a wet place, with many of the conditions we hold sacred to life. Liquid water may still exist below the surface, and with it, simple microbes or photosynthetic bacteria.

Mars' south pole contains huge amounts of frozen water, and recent changes in craters and sediment deposits suggest that liquid water flows sporadically on the surface. Flash-flood gullies and subsurface geysers may offer a safe retreat for microbes and even simple plants, sheltering them from solar radiation. Scientists of some repute suggest that transient dark spots recorded in NASA’s fly-by imagery represent bacterial colonies. As springtime sunshine penetrates the ice, these organisms stir and photosynthesis begins. Pockets of liquid water form, protected from instant vaporization until exposed to the ruthless Martian surface. Once revealed, our cosmic brethren desiccate and blacken. 

Blasted Martian landscape
If life is a simple matter of electrified chemistry, we should find multiple births in life’s cradle. But every Earthling shares a common genetic ancestry, and it seems that the “vital spark from inanimate matter to animate life happened once and only once, and all living existence depends on that moment.” You can’t just zap the primordial soup and create life.There are a few more ingredients in our self-replicating confection.

The most fundamental is the cell membrane, collecting and concentrating life’s raw ingredients into tiny reactive beakers. Second, our inert bubble needs a spark: a source of energy to defy, at least temporarily, the laws of thermodynamics. Life must acquire energy rather than lose it if it is to find perpetual motion.

On Earth, bacteria break down molecules and consume their energy. The  methanogens eat methane and wash it down with water. Other bacteria dine on sulphur, or survive on water alone. These ancient children feed on the primal matter of Earth. These are the extremophiles, lurid “colored smears on the surfaces of rocks” that make their homes in Earth’s forsaken places: boiling sulfuric volcanic vents, lightless ocean seeps, and the scalding flatulence of explosive geysers. They are gifted problem-solvers from a time before the Sun’s power was unlocked, and rich subjects for Biomimicry. Chances are, if we find life on Mars, it will be a similar case of arrested development. In fact, our methanogens grow beautifully on simulated Martian soil. Who knows, maybe someday their extremophiles will inspire our innovations.
Possible water-formed gullies on Mars

On the third rock from the Sun, Earthlings went even further. By striking a flint on the now-ubiquitous green pigment, chlorophyll, they tamed fire. With each iota of light energy captured, a little green creature puffed a single breath of life-giving oxygen into the larval atmosphere, to be gobbled up by the oxidizers of this New World. They spread and puffed away, until finally, the photosynthetic bacteria produced oxygen faster than it could be locked away. Our original life-givers still quietly exhale today in the far-away acidic and saline lakes where grazing snails fail. Life creates conditions conducive to life, and so cooperation and collaboration were there from the beginning. Judging from our own planet, we might expect to find an entire interconnected ecosystem dining on light energy and methane just below the Martian surface. 

Polar ice cliffs: NASA/HiRISE Team
At some point, Earth’s inhabitants got vastly more creative still, and our evolutionary history radically diverged from the scientists’ most wildly imagined Martian fantasies. On Earth, multi-celled creatures evolved and invented sex. Today, most Earthlings scramble distinct sets of genetic information together and dole them back out in fresh combinations to their children, testing each one on our big blue lab.

Are we all Martians? Bobak 'Mohawk Guy' Ferdowsi
If we do find a Martian, what are the chances this rare mutation (life) occurred independently? Isn’t it more likely that our neighbor down the street is a sister from a different father, especially since our rovers idle at the Martian curb as we speak? Our ancient climates were similar: could life flit between them like finches in the Galapagos? A billion tons of Martian rock has surfed the cosmic current to our shores, and some microbes and even lichen can survive such space journeys. If life blew to Earth on a Martian wind, like dandelion fluff across the Pacific, the spark that binds us is still singular and special. Life remains “nothing less than the transformation of matter itself,” forging indifferent elements into a vital, self- regenerating system, the elusive perpetual motion machine. 

Such journeys evoke Columbus-era species-swaps, like Pocahontas’ descendants returning home from a life-altering vacation. Maybe all of us, from slime mold to spider to ape, are born of distant ancestors whose separated-at-birth children toil on beneath the Martian ice. You can’t help but think the ones left behind got the short end of the stick. How much more miraculous are Earth’s ecologies compared with even the richest Martian ecosystem? Where are the rainforests, with over 600 insect species in a single tree, each with a pocket penknife of surprising talents? Where on Mars will we find ten million species or more coexisting in bewilderingly interconnected networks? Where does life beget conditions conducive to life? Curiosity’s blasted vision suggests we won’t find it. “In the beginning, there was dust, and one day the great, improbable experiment of life will return to dust” and primeval cells like those we imagine on Mars will once again “spread their colored slime over the Earth, even as creatures of complexity and elegance know their last days.” Until then, let’s enjoy our vacation.

All quotes and much inspiration are from Richard Fortey’s fantastic evolutionary memoir, Life.

Wednesday, August 1, 2012

Team Banana

Last month, in Tlapacoyan, our team was challenged to create a better way to pack fruit and get it to Mexico City with less spoilage. Yihad Ghattas is our meticulous Colombian urban planner. Our architect, Roberto Ferrar, is from Mexico City, and I am the biologist. We start by asking what kinds of fruit are grown in the region. What are the real problems faced by the growers? We interview several locals. The range of fruit is bewildering, varying fantastically in size, durability, and requirements for ripening, humidity, and temperature. Lychee, mango, oranges, limes, grapefruits, papaya, avocado, pumpkins, mamey, sapote, guanabana, melons, and even coffee…how can we possibly come up with a solution for all these? Chucho, a former grower, tells us that the most important fruit in the region is the banana. And the Tlapacoyans are not happy about the way it is grown.

Tlapacoyan is a region of stunning beauty, beloved by its people. Here, the Rio Bobo churns forcefully through a dramatic primeval landscape of ancient figs and giant ferns, dotted with colorful orchids and bromeliads, dripping with pulsing slime molds, and laced with the intricate webs and nets of an endless array of skillful and patient hunters. Team Banana picks its way carefully through coursing streams of leafcutter and army ants to get to Bobo’s sandy, bouldered shore, framed by towering trees, and littered with the corpses of hundreds of plastic bags.
Banana bags and monoculture

Covering the penca

Over the ceaseless rumbling of the river and the deafening buzz of cicadas, Chucho tells us how to grow bananas. A single violet ‘penca’ balloons perversely from each tree. These are sequestered from insects with a transparent blue baggie, which has the added function of concentrating levels of the banana’s own ethylene, thus hastening ripening. The grower cleaves the penca from the tree with his machete, and the purple bruise fades to sickly chartreuse as the bags are peeled off and discarded, sometimes catching the air to sail off like jellyfish. The bananas are plunged into the ‘carburo,’ a kind of liquid charcoal that serves as artificial ripener, and divided into family-sized bunches. These are placed into a second baggie, stacked into cardboard boxes, and loaded onto an open truck. The trucks rumble off, in a thick cloud of diesel exhaust, toward the enormous distribution center in Mexico City. Days later, the trucks return with the boxes and plastic baggies (which the distributor does not want), and more jellyfish make their way to the shore.The banana trees are planted in endless monotonous waving rows, right to the edge of the jungle. It takes a full year for these ragged shoots to produce. Once the tree yields its solitary fruit, it dies, and the fecund forest floor becomes barren, the soil degraded. The richness of the rainforest depends on the incessant rhythm of scurrying feet, scrambling mouths, and pulsing decay. When this dance is interrupted, the nutrient cycle stops. It is difficult to start the music back up.

 The Tlapacoyans want to feed their families, which extend voluminously backward and forward in time to include ancestors and grandchildren. Their livestock grazes peacefully between the ancient temples, sacred ball-fields, snaking stone walls and manicured waterways built by the Old People three thousand years ago, in a past that still seems present. And not because they left their plastic bags lying around.

Our task becomes repelling insects, ripening quickly, and packing efficiently, while considering the integrity of the land and maintaining a living for the growers. The bananas must be ready to sell on arrival. The faster the growth-to-market cycle, the more money to be made. Profit, People, Planet, the three 'P's. Especially Profit. It’s time to biologize the question: How does Nature protect, pack, and preserve? We brainstorm a long list of possible organisms and structures, and observe that Nature goes into high gear protecting, preserving, and packing its most precious cargo. Packets of priceless information are horded jealously in genetic vessels of all kinds: eggs and larvae, nests of birds and colony insects, seeds, pods, and cones, even spittlebug foam.

We discard coconuts in favor of honeycomb, a brilliantly lean modular system for protecting larvae, preserving nectar, and packing honey. The hexagon permits no wasted space, and cells and bubbles naturally form hexagons when pressed together. Buckminster Fuller, the genius behind the geodesic dome, knew this. A honeycomb of lightweight, durable, locally available, and ultimately biodegradable bamboo boxes will stack perfectly in the trucks. We can even fold them down for the return trip, using a simple locking rod patterned on the flamingo knee joint. Roberto turns engineer, working the numbers, making blueprints, and constructing a passable model from BBQ skewers and scotch tape.  

Our Champions: the Bonete pod and the multi-storied forest

More champions: Sea sponge and spider web

Can we combine this with a peapod duffel-bag structure on the penca to keep out the insects? We walk through the forest, searching for suitable seedpods. We come up with Jacaratia mexicana, the Bonete. This tree grows in the seasonal rainforest, and sports a tough cone-like waterproof ‘berry’, which in cross-section appears as a pentagon. Moisture collects on the exterior and is shunted away to the ground. The berry stays dry until the seeds are ready; the pod breaks free, falls into the moist ground below, and dehisces at huge force, splitting its sides to fire the seeds out for germination. Can we make a bag inspired by the Bonete?

And what about ripening? At home, I tuck unripe fruit in a brown paper bag next to a red apple. The apple emits ethylene, ripening its companion. We find Jose Carlos Cervera, a young Yucateco botany professor who spends his days measuring the exact gaseous inputs and outputs of a couple of individual succulent plants. Grown far too intimate with the secretions of his subjects, Jose hates plants. He’s our man: he tells us about the wide assortment of 'climacteric' fruit that produce ethylene: peppers, pumpkins, bananas, avocados, all locally available. We can grow these alongside the bananas, mimicking the multi-storied forest around us, and simply chuck a few into each box as we pack. But which one? Peppers like to be dry, and avocados are big and shady. Nobody seems enthusiastic about sapote. We settle on pumpkins, grown throughout the year, available in many sizes, and thriving on neglect. In fact, the ancients traditionally planted maize this way, alongside squash and beans, which fix nitrogen into the soil.

Honeycomb and flamingo knees

We need to pull this system of disparate parts together. The sea sponge comes to mind: a porous bag of tissues inside a tough exterior tube. Water draws nutrients through the tube, to be filtered for consumption by the porous bag. Or spider webs, passively filtering insects while the breeze passes through. We can use these strategies to keep insects out, while drawing ethylene in. Our plan emerges: a mesh bag, surrounded by a waxy canvas tube, is tied over the developing penca. The bottom mesh receives ethylene from the pumpkins growing below, while denying entrance to insects. The penca is cut down and separated into bunches. Our hexagonal bamboo structure goes into the bag, and the bananas are packed into it, along with a few small pumpkins. The bag is closed and loaded onto the truck. After unloading, the units are folded down so other items can be brought back to sell in Tlapacoyan. When the grower returns home, he is greeted by the delicious smell of frijoles, platanos, y calabaza. Con mucho gusto, Tlapacoyan!
Team Banana: Roberto Ferrer, myself, and Yihad Ghatta