Those of you familiar with Blindsight‘s Scramblers may remember this quirk about their physiology: they didn’t keep all their metabolism on the inside.
“I don’t think Rorschach’s magnetic fields are counterintrusion mechanisms at all. I think they’re part of the life-support system. I think they mediate and regulate a good chunk of scrambler metabolism… If I’m right, I’m not even dealing with complete organisms here.”
I kept it all fuzzy and hand-wavey — microscopic shards of magnetite in scrambler cells, dancing to the precise twitch of Rorschach’s filigreed magnetic fields — because I didn’t in truth have any idea how an inside/outside metabolism would really work. I thought it was a really cool idea, though.
Count on Nature to think of it a few billion years before I did. Are you ready for metal-breathing microbes?
I wasn’t, not until last Thursday. That’s when I received an e-mail from one Jake Cohen, a dude who gets more out of my writing than some might consider normal. It happens, occasionally: someone drops a line mentioning that Blindsight inspired her degree in cognitive linguistics, or that an idea gleaned from Starfish allowed him to commit the perfect murder, or that Maelstrom‘s take on digital wildlife informed some project over at Lawrence Livermore that no one’s allowed to talk about1. Jake, a microbiologist by trade, admitted to being especially fond of my rifters books. He pointed me to the Harvard lab where he’s about to start a PhD on hydrothermal vent ecology, and I dutifully clicked the link to check it out.
Which is where I encountered the photo caption “Extracellular electron transfer experiments at 1 kilometer below sea level in the Monterey Canyon”, slipping past almost too quickly to notice on Prof. Girguis’s splash page.
Extracellular electron transfer? Does that mean what I think it does?
I wrote Jake back, and yes: yes it does. But don’t take my word for it, or even his: say hello to Shewanella oneidensis — a bacterium that, while facultatively aerobic, can get by in anoxic environments by breathing metals2. Here’s the money shot:
“…can also thrive without the gas if it must, thanks to energy-generating chemical reactions that transfer electrons from inside its cells to outside minerals that contain metals such as iron.”
—or, to quote my newfound go-to guy at Harvard, “[it] works mostly like a regular electron transport chain, except instead of the terminal electron acceptor being inside the cell, those bacteria use a carrier molecule to pick up those electrons and shuttle them outside of the cell to an acceptor they’re growing on.” Apparently this also raises certain commercial possibilities in the biobattery department.
Inside/outside metabolism. Holy shit.
I wish I’d known about this while I was writing Blindsight. You can be damn sure it’s going to make a walk-on in Echopraxia, though.
1 I exploit these folks mercilessly, trading on their goodwill by hitting them up for expertise the next time I want to write about something without having to get a goddamn degree in it first.
2The Science article contains an alleged link to the original PNAS online paper, but it’s broken, and PNAS’s own early-edition abstracts for the 25th don’t seem to list it. Don’t know what’s up with that.