The Sixth Extinction: An Unnatural History

Spencer gathered from around Castello Aragonese at first appear inert—
to my untrained eye, possibly even dead. But after a while, they set about
waggling their tentacles and scavenging for food. There is a starfish
missing a leg, and a lump of rather rangy-looking coral, and some sea
urchins, which move around their tanks on dozens of threadlike “tube
feet.” (Each tube foot is controlled hydraulically, extending and retracting
in response to water pressure.) There is also a six-inch-long sea
cucumber, which bears an unfortunate resemblance to a blood sausage
or, worse yet, a turd. In the chilly lab, the destructive effect of the vents is
plain. Osilinus turbinatus is a common Mediterranean snail with a shell of
alternating black and white splotches arranged in a snakeskin-like
pattern. The Osilinus turbinatus in the tank has no pattern; the ridged
outer layer of its shell has been eaten away, exposing the smooth, all-
white layer underneath. The limpet Patella caerulea is shaped like a
Chinese straw hat. Several Patella caerulea shells have deep lesions
through which their owners’ putty-colored bodies can be seen. They look
as if they have been dunked in acid, which in a manner of speaking they
have.
“Because it’s so important, we humans put a lot of energy into making
sure that the pH of our blood is constant,” Hall-Spencer says, raising his
voice to be heard over the noise of the running water. “But some of these
lower organisms, they don’t have the physiology to do that. They’ve just
got to tolerate what’s happening outside, and so they get pushed beyond
their limits.”
Later, over pizza, Hall-Spencer tells me about his first trip to the
vents. That was in the summer of 2002, when he was working on an Italian
research vessel called the Urania. One hot day, the Urania was passing by
Ischia when the crew decided to anchor and go for a swim. Some of the
Italian scientists who knew about the vents took Hall-Spencer to see
them, just for the fun of it. He enjoyed the novelty of the experience—
swimming through the bubbles is a bit like bathing in champagne—but
beyond that, it set him thinking.