Crysomallon squamiferum, commonly known as the scaly-foot gastropod, was discovered in 1999 in the Kairei “black smoker” field on the Central Indian Ridge, at a depth of 2420 metres. The shell is uniquely structured to crack when hit, but in a way that absorbs energy. Image Credit: Fisheries Meiwa
Deep-sea snail shell structure yields hints for new protective body Armour
A discovery deep in the Indian Ocean, along a volcanic rift known as a "black-smoker" is just now coming to light in its significance as a natural protective structure against pinching and piercing blows. The attention is being brought by a couple scientists doing research at the Massachusetts Institute of Technology (MIT) on structures that could help in the development of the next generation of protective human body Armour.
What has the focus of this attention on a deep-sea snail (Crysomallon squamiferum, commonly known as the scaly-foot gastropod) is its unique shell which is made up of the snail's ability to incorporate iron sulfide particles into its shell, and in a skirt along the edges for protection against the blows it receives from predator deep-sea Crabs.
The Crysomallon squamiferum, commonly known as the scaly-foot gastropod is small. It is only about two to three centimeters in length. Image Credit: Department of Microbiology - NC State University
This excerpted and edited from the New Scientists -
Deep-sea snail shell could inspire next-gen armour
New Scientists - 20:00 18 January 2010 by Shanta Barley
Christine Ortiz at the Massachusetts Institute of Technology and her colleagues studied the snail's three-layered shell to find out how it defends itself from crab attacks.
To assess the shell's strength and stiffness, they penetrated it with diamond-tipped probe – applying the same amount of force that an attacking crab's claws might use. They then used the data to model the shell's layers and launched a virtual crab attack on it.
It turns out that the snail employs some unique tricks to protect itself. For example, the shell's outermost layer consists of strong particles of iron sulphide created in the hydrothermal vents, each around 20 nanometres across, embedded in a soft organic matrix secreted by the snail. This structure is designed to crack when hit, but in a way that absorbs energy.
Cracks spread only by fanning out around the iron sulphide particles. This "microcracking" not only absorbs energy, it also ensures that larger cracks do not form. What's more, the particles of iron sulphide may blunt and deform intruding claws, the study suggests.
A thick, spongy middle layer acts as padding to dissipate further the energy of the blow. This makes it less likely that the mollusc's brittle inner shell, which is made of calcium carbonate, will crack.
The middle layer may be an important adaptation to life at a deep-sea hydrothermal vent, suggests Cortiz: the acidic water near black smokers dissolves calcium carbonate and so can quickly enlarge fractures.
The three-layer design could be used to improve body armour "without the addition of excessive weight", says Ortiz.
The idea of coating armour in iron-based nanoparticles that dissipate the energy of a blow by generating microcracks is "largely unexplored in synthetic systems" and particularly promising, says Cortiz.
Helmets, motorbikes and Arctic pipelines that collide with icebergs, leading to costly oil spills, could also benefit, says Cortiz, who is also exploring the armour systems deployed by the marine molluscs known as chitons, sea urchins, beetles and a fish known as the Senegal bichir.
So, in the not so distant future ... here on this Oblate Spheroid, one will be riding their Harley-Davidson at a speed something other than a snail's pace, not clad in "leathers" but sporting the colors of rust cast off from embedded iron-based nanoparticles.