Glass sponges.In 2001, during an oceanographic expedition in Hawai, a big population of the marine sponge Sericilophus hawaiicus was discovered. This sponge is also known as “glass sponge”, because its skeletal elements spicules are made of silica (glass). These sponges live at depths of around 400 meters.
The team, scientists from the USA, Canada and Spain, developed several tests “in vivo”, using an oceanographic submarine (PISCES V) from the Hawaii University. One of the scientists was Manuel Maldonado, from the Centro de Estudios Avanzados de Blanes (CEAB) of the CSIC. Maldonado collected samples of the sponges to keep studying in the future their skeleton.
Most sponges have skeletons with spicules of sizes between few micrometers and one millimeter. But the “glass sponge” has bigger spicules, some of them giant, with sizes reaching up to 50 centimeters.
It is well known that silica has a good capacity to transmit light. Nevertheless, when scientists did analyze the properties of these spicules transmitting light, the outcome was astonishing. The spicules behaved as an outstanding efficient optical fiber: not only could guide internally the light-beam without losses, but also generated new light with a different wavelength.
The “glass sponge” has large spicules, some of them giant, with sizes reaching up to 50 centimeters
This property is known in Photonics as “supercontinuum generation in the light transmission”, meaning that the spicules not only can transmit internally the light received without losses but they also broad the spectrum and project at the other end a light beam with a wider spectrum.
The structural properties that give spicules these properties are not well known yet. Nevertheless, as Maldonado explains, “we hypothesize that two characteristics could explain the behavior: firstly, the high isotopic purity of the spicules of silica, which could favor the light transmission and, secondly, contrarily to optical fibers, the silica in sponges is nanostructurally embedded with organic materials (chitin), organized in an internal structure that favours the supercontinuum generation”.
Scientists keep researching in the project PBS, in order understand the properties that would explain the notable optical properties of these sponges and to apply in the future generation of computers and optical fiber.