Let's Do What Plants Do

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Morton delivers, but he takes his time in the driver's seat, first spending a rather luxuriant 300 pages on molecular biology and geophysics. Morton himself calls his book "long" and "odd." It is eccentrically divided into three sections. The first, titled "In the span of a man's life," explains the significant, often inspiring, recent scientific discoveries that yielded the secrets of the chloroplast. "In the span of a planet's life" addresses the ways in which water and nutrient cycles have shaped our world, and the last section, "In the span of a tree's life," focuses on the two centuries it has taken complex plant-eaters -- us -- to disrupt the hard-won carbon cycle.

It all comes back to carbon.

The miracle of plants is that they can take this element out of inorganic stuff and make something organic with it: sugars, which provide the fuel that drives every life process on earth. To create this chemical energy, plants need carbon dioxide and hydrogen, which they get by splitting water into its elemental parts using energy from the sun. The waste product, luckily for us, is oxygen. Scientists knew this by the turn of the twentieth century, but they didn't really know how it worked.

It wasn't until the advent of particle physics that scientists could peer inside the photosynthetic process using radioactive isotopes. In one of his usually interesting asides, Morton points out that the "Rad Lab" at the University of California, Berkeley, which manufactured the most useful isotope, carbon-14, later isolated plutonium as part of the Manhattan Project. After the war, Andrew Benson and Melvin Calvin, two chemists, arrived at the Berkeley lab and started growing algae in big flattened flasks they called lollipops. The scientists fed the algae glowing carbon-14 and watched in awe as the chloroplasts folded the inorganic carbon into 5- and 7-carbon sugars in a complex process that became known as the Calvin-Benson cycle.

They also discovered a critical catalyzing protein called rubisco, which is, as Morton writes, "responsible for knitting the dead carbon dioxide of the earth's atmosphere back in the living tissues of its vegetation." But the big breakthrough came through a better understanding of photons -- the energy particles that escape from the sun as the result of random fusion reactions. Eight minutes after a photon leaves the sun it bumps into a green chlorophyll pigment inside a leaf. There it turns into usable energy by igniting an electron-transfer chain that splits water and creates sugar and oxygen. Through this process, replicated billions of times every day in billions of plants the world over, the earth breathes. Over 2.4 billion years, this process created the  atmosphere that envelops our planet today.

I know what you're thinking: here comes the grim part. Yes, we have seriously damaged the earth's carbon feedback loop, with some dire knowable and many unknowable consequences. But Morton is a pretty straightforward guy, and he leaves apocalypse to the novelists. With a boyish faith in science, he believes that photosynthesis -- or, more specifically, as yet undiscovered photosynthesis-inspired sources of energy -- will come to our rescue.

Continued...