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26 November, 2010

Abyssal Vent


In an effort to educate my deprived children--they have no broadcast or cable TV to tell them what's what--I recently introduced them to the 20th Century nature show, complete with the voice of David Attenborough. Regrettably, it was just his voice, no shots of his cavorting about the globe in old-school high tops.

I say 20th Century, although Blue Planet was aired in 2001, and I may as well address that discrepancy before some bored and bitter internerd acts like he noticed it first. To begin with, a year or two off ain't nothing in the scheme of things, and for an archaeologist it's dead-on. Second, the images you see on there are 20th Century, you only watched it later, you moron; editing and all the post production takes time. Third, and really the only important point in the bunch: Blue Planet is a decent nature show, a species that arose and flourished in the last century, but is in grave danger of extinction now.

And even if they make their way to a house or hotel with cable TV, the kids aren't likely to run across a similar beast. In the doddering final quarter of the last millenium, demigods like Attenborough and Page narrated masterpieces of the nature show genre while the rest of civilization fell, finally landing in the ilk of shark week, cryptozoology, and extreme animals. They read scripts laden with actual information founded in science, scripts with the confidence to sit silent while clever editing and sublime photography (itself patient and informed enough to be at the right place at the right time) conspired to tell the tales.

Anyway, we sat there watching the episode on the deep, dwellers in the dark zone. Benthic beasties beyond the reach of the sun, subsisting on the droppings of the well-lit seas above. Browsing the drifts of marine snow, filtering morsels and motes flung down toward them by currents, ambushing and hunting each other. But ultimately, or so we though and were taught through most of the last century, ultimately all life depended on the sun. Critters with no notion of the sun depended on its by-products for life, and when its flame faltered, all would perish.


If you got National Geographic you knew by 1980, if you were a marine biologist you knew earlier (maybe), but the glacial pace of textbook revision in the age of paper made sure that nobody else knew about this fact for many more years: along the great oceanic rift zones occurred some vents spewing hydrogen sulfide that were teeming with life. Polychaete worms, vast mats of bacteria, mussel beds, weird crabs (which is saying a lot),...all of these freaks living off of chemical energy. No sun, no photosynthesis, no herbivores, a food chain completely unlinked from all the others.

Then, a few years later, abyssal surveys in the Gulf of Mexico found "cold seeps," chemicals oozing up through the ocean floor to form lakes, their shores lined with communities of extremophiles, creatures capable of sucking life from methane, which I hope you will pronounce in the Attenboroughian way, "MEE-thane." [And yeah, I said 'lake' and 'methane,' o ignant internerd, because at that depth, the gases stay liquid.]

I have not yet heard how these unique ecosystems, having freed themselves from the vagaries of topside weather and the thousand other risks up there, have coped with the Deepwater Horizon Spill. Just when you've perfected the art of living off one kind of poison, along come a river of something else. Damn, evolution used to be easier before the humans got out of hand.

Anyway, as I am sure you can all see by now, the point of this whole entry is of course this: Life can arise where the sun don't shine, it can live on farts alone. And if sulfurous exhudations and mee-thane are all it takes to support a rich community of creatures, then long after the sun goes cold, life will hang on tenaciously around my own abyssal vent. There is hope beyond that most frightening of ends.

Assuming my supply of beans holds out.

* Oh, and since I don't get down there much myself, I lifted the photo of some extremophiles from:
(2005) Tubeworm May Live Longer by Cycling Its Sulfur Downward. PLoS Biol 3(3): e108. doi:10.1371/journal.pbio.0030108

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