How Water Flows Inside a Sea Sponge
Zero-Energy Deep-Sea Sponge Inspires Energy-Efficient Designs: NYU Study
The Venus flower basket sponge, a deep-sea creature, possesses an intricate skeleton that allows it to filter feed using only the faint ambient currents of the ocean depths, without the need for pumping. This discovery, made by an international research team co-led by the University of Rome Tor Vergata and NYU Tandon School of Engineering, could inspire engineers to design more efficient chemical reactors, air purification systems, heat exchangers, hydraulic systems, and aerodynamic surfaces.
The sponge’s ability to passively draw in food works only at the very slow current speeds – just centimeters per second – of its habitat. “From an engineering perspective, the skeletal system of the sponge shows remarkable adaptations to its environment, not only from the structural point of view, but also for what concerns its fluid dynamic performance,” said Giacomo Falcucci of Tor Vergata University of Rome and Harvard University, the paper’s first author.
The Sponge’s Intricate Skeleton
The Venus flower basket sponge (Euplectella aspergillum) has a delicate, glass-like outer skeleton made of silica. This skeleton is composed of a spiral staircase-like structure of fused spicules, or glass rods. The spicules are arranged in a way that creates a porous, lattice-like frame.
How the Sponge Filters Food
The sponge draws water into its central body cavity through its porous, lattice-like frame. The water flows through the sponge’s body cavity and exits through the osculum, a large opening at the top of the sponge. As the water flows through the sponge, it filters out plankton and other marine detritus. The sponge then digests the food particles.
Passive Flow Control: Zero-Energy Filter Feeding
The sponge’s ability to filter feed without pumping is due to its unique skeletal structure. The spiral, ridged outer surface of the sponge creates a pressure gradient that draws water into the sponge’s body cavity. This pressure gradient is created by the Bernoulli effect, which states that the pressure of a fluid decreases as its velocity increases.
As the water flows through the sponge’s body cavity, it encounters the sponge’s porous, lattice-like frame. This frame slows down the flow of water, which increases the pressure inside the sponge’s body cavity. The increased pressure drives the water out of the osculum.
Biomimetic Engineering Insights
The sponge’s unique skeletal structure has inspired engineers to develop new energy-efficient designs. For example, engineers have developed a new type of air filter that uses a similar porous, lattice-like structure to filter out dust and other particles. This new air filter is more energy-efficient than traditional air filters, which use fans to draw air through the filter.
The sponge’s skeletal structure could also be used to design more efficient heat exchangers, hydraulic systems, and aerodynamic surfaces. By mimicking the sponge’s ability to passively control flow, engineers could design devices that are more energy-efficient and less likely to fail.
Conclusion
The Venus flower basket sponge is a fascinating creature that has evolved a unique way to filter feed in the deep sea. Its intricate skeletal structure allows it to passively draw water into its body cavity and filter out food particles without the need for pumping. This discovery could inspire engineers to design more efficient energy-efficient technologies.
Deepika 
Divya