Watch this sea snail flutter through the ocean just like a butterfly
Meet the sea butterfly. Unlike most species of zooplankton that occupy the all-important base of the marine food web, this sea snail earned its nickname by behaving more like an insect, fluttering its wings from top to bottom and contorting its tiny body to propel itself upward through the water column.
Nearly all other species of zooplankton use their limbs like paddles to move through the water, according to a new study in the Journal of Experimental Biology.
You May Also Like
In the study, researchers from Georgia Tech collected hundreds of the tiny mollusks from the Pacific Ocean and used high-speed cameras to record their movement, seeking to figure out precisely how and why the sea butterfly behaves like such an insect-plankton hybrid, or in the scientists' words, "a remarkable example of convergent evolution."
What they found, using high-speed photography, was that the sea butterfly moves through the water similarly to how tiny insects like thrips and fruit flies fly through the air: by flapping its wings in a figure-eight pattern.
"Our measurements strongly indicate that L. helicina uniquely employs lift-based swimming instead of drag-based swimming used by nearly all zooplankton," the study states.
The scientists discovered that the sea butterfly stands alone in contorting its body in ways that complement its strokes through the water to accentuate lift.
"Snails evolutionarily diverged from flying insects 550 million years ago,” said Donald Webster, a Georgia Tech engineering professor, in a press release. “Hence, it is amazing that marine snails are using the same figure-eight wing pattern that is typical of their very distant airborne relatives.”
Both the sea butterfly and particular insect species use a Weis-Fogh clap-and-fling mechanism (named after the Danish zoologist who first described it), during which it claps its wings together and then rapidly flings them apart to generate enhanced lift.
However, the sea butterfly sets itself apart by rotating its body 60 degrees as it performs its power stroke, making sure the weight of its shell doesn't cause it to sink to the bottom of the ocean.
“Insects and birds don’t typically rotate their bodies in a similar manner to generate lift,” Webster said. “By rotating their shell during each stroke, sea butterflies put their wings in a position to always generate upward thrust and fly forward."
One of the motivations for this study is to determine how sea butterflies and other pteropods may respond to increasingly acidic ocean waters.
Oceans are absorbing more carbon dioxide because of the burning of fossil fuels for energy. When dissolved into seawater, carbon dioxide eventually forms carbonic acid, which has many impacts, including impeding some species' ability to create and maintain their calcium carbonate-based shells.
According to Georgia Tech, scientists hope to conduct research on how ocean acidification-related changes in shell composition and fluid viscosity will affect the sea butterfly's ability to rotate and fly upward.
The team is also interested in using the biomechanics of this creature to help engineers create tiny autonomous robots that swim in the ocean, gathering data as they do so.
Andrew Freedman is Mashable's Senior Editor for Science and Special Projects. Prior to working at Mashable, Freedman was a Senior Science writer for Climate Central. He has also worked as a reporter for Congressional Quarterly and Greenwire/E&E Daily. His writing has also appeared in the Washington Post, online at The Weather Channel, and washingtonpost.com, where he wrote a weekly climate science column for the "Capital Weather Gang" blog. He has provided commentary on climate science and policy for Sky News, CBC Radio, NPR, Al Jazeera, Sirius XM Radio, PBS NewsHour, and other national and international outlets. He holds a Masters in Climate and Society from Columbia University, and a Masters in Law and Diplomacy from The Fletcher School at Tufts University.
