The primary reactions in photosynthesis—the first steps in plants’ conversion of sunlight energy into energy stored in carbohydrates—are incredibly efficient. And in a new study in Nature, chemists reveal that they may have found part of the reason why: quantum mechanics.
A couple years ago, scientists first showed in bacteria proteins that the electrons were moving according to a quantum mechanical phenomenon called coherence, rather than abiding by the classical laws of physics. But where those early experiments had been cooled to 77 kelvins (–196 degrees Celsius)—this experiment was the first conducted at room temperature, 294 K, to replicate such effects [Scientific American]. Thus, the new study, which was done on marine algae, suggests this phenomenon can occur in a living biological system.
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Part animal, part plant, bright green, and totally bizarre: Meet the sea slug Elysia chlorotica.
Biologists already knew that this organism, native to the marshes of New England and Canada, was a thief that somehow pickpocketed genes from the algae it eats. At last week’s meeting of the Society for Integrative and Comparative Biology in Seattle, researcher Sidney Pierce said he has found that the slugs aren’t just kleptomaniacs—they use the pilfered genes not only to make chlorophyll, but also to execute photosynthesis and live like a plant. Said Pierce: “They can make their energy-containing molecules without having to eat anything,” Pierce said. “This is the first time that multicellular animals have been able to produce chlorophyll” [LiveScience].
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In a salty hot spring near Mono Lake, California, researchers have found two new species of bacteria that use arsenic for photosynthesis, and require no oxygen to fuel the process. Researchers say the bacteria may be similar to those that existed on primordial Earth where oxygen was scarce, and may illustrate an important stage of how early life developed in mineral-rich waters over 2 billion years ago.
Arsenic is well-known for its toxicity; it was used so often as tool for homicide in the 1800s that it earned the nickname “king of poisons” [The Scientist]. Yet the newly discovered bacteria can not only tolerate the element, they require it to survive. One of the first steps most organisms perform in photosynthesis is to split water molecules, creating oxygen. Oxygen donates energy in the form of electrons to other molecules, setting off a chain reaction that eventually results in the building of sugars for the organism’s own food. For the red and green bacteria found in Mono Lake, arsenic plays the role of oxygen [Science News].
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Who knew that a white spruce in northern Canada, a red maple in Pennsylvania, and a mahogany tree in Puerto Rico have so much in common? Their environments are certainly very different, with icy winds buffeting the spruce tree’s needles and hot, humid air bathing the mahogany tree’s leaves. But despite these external variations, a new study shows that inside each tree leaf (or needle) it’s always just the right temperature for the delicate and vital process of photosynthesis, and the leaves are responsible for keeping that thermostat steady.
The findings, published in Nature [subscription required], show that trees all across North America favor the temperature of 70 degrees Fahrenheit for the photosynthesis process, which uses sunlight to convert carbon dioxide into oxygen and sugars. To keep in that comfort zone, they’ve come up with some clever adaptations. Trees release water, and during hot times, that botanical sweat cools them down. And trees that grow in cold places tend to cluster their leaves. These tight formations can affect the rate at which leaves lose heat on cold days, just as fingers pressed together in mittens stay warmer than fingers separated by space in gloves [Science News].
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