Fluid Dynamics Study of Oceanic Organisms in Antarctica
Dr. Deepak Adhikari - an University of Minnesota Aerospace Engineering and Mechanics graduate - recently set out on a post-doctoral research expedition in Antarctica in order to study how fluid dynamics of swimming organisms provide early warning on ocean acidification.
"The goal of our research team is to develop a behavioral assay to provide an early warning on the effects of ocean acidification," said Adhikari. "This is achieved by selecting a planktonic species in the Polar Regions that is vulnerable to ocean acidity, and then studying the changes in bio and fluid mechanics of their propulsion."
In particular, Adhikari and his team are interested in planktonic pteropod (Limacina helicina) - also known as sea butterflies - because they have aragonite shells that dissolve as ocean acidity increases. As their shells get thinner, weight and buoyancy of the pteropod changes causing them to swim differently. With a team of biologists and engineers, Adhikari traveled to Antarctica in pursuit of studying these organisms.
"We used tomographic particle image velocimetry (PIV) and multi-camera imaging technique to get the 3D flow velocity field and kinematics of the swimming organisms," said Adhikari. "Tomographic PIV is an advanced technique used to measure volumetric flow velocity field."
Adhikari learned about this technique as a PhD student in Professor Ellen Longmire's lab. He designed a portable tomographic PIV set up, and implemented it successfully at Palmer Station, Antarctica in April - May 2014.
"Since many of these planktonic organisms are very delicate, transporting them alive from Antarctica to United States is difficult," said Adhikari. "This made it necessary for us to take all our equipment to Antarctica."
The results obtained from tomographic PIV will be analyzed to learn more about pteropod swimming. Furthermore, the experimental data will allow their CFD collaborators at Johns Hopkins University to compute and compare the flow field.
To learn more, visit the United States Antarctic Program (USAP) project details website: http://www.usap.gov/scienceSupport/sciencePlanningSummaries/2013_2014/scienceSummariesAction.cfm?formAction=detail&ID=610