The intertubes are abuzz with the newest findings released by NASA, explaining the discovery of a new form of life, one that incorporates arsenic throughout its biochemistry as a replacement for phosphorus. Alien biochemistry! Tribbles! Horta! It could all be out there! I hate to be the wet blanket at the Gene Roddenberry party, but there’s less here than meets the eye.
I just got done watching the NASA online presentation, and what I saw was a slick production meant to spur excitement in NASA, an agency that is increasingly under fire for its mission failure and mission creep.
The experiment described is actually fairly common biochemical research: you take some bacterial sludge, isolate the bacteria, grow their populations, expose them to something toxic, deprive them of certain nutrients, and you see if some of them are pre-adapted to survive. As the Post explains, the researcher “took mud from the briny as well as toxic lake into the lab and began growing bacteria in Petri dishes. She gradually replaced phosphate salt with arsenic until the surviving bacteria could grow without needing the phosphates at all.”
Big whoop. I did similar research as a lab tech in grad school, to see if I could find pre-adapted bacteria that could break down highly toxic chemicals. Some always did. But in such experiments you can’t know whether the mutation that allowed this to occur happened in your lab, or whether such organisms exist at any numbers in the wild. Here’s how it works: you hit a large population with something lethal, and sure, you’ll kill a bunch, maybe most, but natural mutation rates combined with a large population means that you’re unlikely to kill them all. Pretty soon, survivors repopulate, and they’re resistant to what killed off so many of their dearly departed kin. Repeat that often enough, and you can select for organisms very different from what’s in the wild. Nature does this constantly in some of the most extreme environmental conditions imaginable, on Earth, and no doubt elsewhere.
But even if such pre-adapted critters are in the wild, you can’t know if they actually utilize this novel biochemistry, or whether they’re simply pre-adapted through random mutation. And there was no mention of the researchers going back and sampling Mono Lake to see if these arsenic-adapted bacteria exist in the wild.
NASA is presenting a routine microbiological experiment as some kind of Earth-shaking discovery that will revolutionize the world—even our understanding of life, the universe, and everything (and justify more life-hunting space probes). Bunk. Biologists have long known that life adapts to a vast range of environmental conditions and available nutrients. This is particularly true in the microbial world, where sheer numbers and natural mutation rates create an evolutionary survival machine that rarely fails—think about antibiotic or pesticide resistance.
There is really only one interesting implication from this new discovery: It shows how desperate NASA is for positive press, and the extent they’ll go to in order to secure it. They must have spent many tens of thousands of dollars for that slick, propagandistic press conference, with its fancy graphic simulations and video productions.