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CRITTER CHEMISTRY
Sea Snails Shod With Iron Sulfide Scales
SOPHIE ROVNER
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COURTESY OF S. BENGTSON AND M. SEGONZNC
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A recently discovered type of sea snail that lolls at the base of black-smoker chimneys in the Indian Ocean differs from other multicellular animals by incorporating iron sulfides in its skeleton, report Anders Warén of the Swedish Museum of Natural History and colleagues [Science, 302, 1007 (2003)]. The snail's foot is covered by overlapping scales of conchiolin--a nitrogenous organic material common in mollusk shells--mineralized with pyrite (FeS2) and greigite (Fe3S4). The snails obtain their starting materials from the hydrothermal vent fluids, which are loaded with dissolved sulfides and metals.
The scales measure up to 8 mm in length and 0.2 mm in thickness. The authors speculate that the armor may protect the animals from predatory snails that employ darts to inject venom into their victims.
The researchers note that the scales and shell of the armored snail shown here are "rusty from storage in low-grade ethanol." |
