USAP-DC

Ocean acidification (OA) poses a serious threat, particularly to organisms that precipitate calcium carbonate from seawater. One organism with an aragonite shell that is a key to high latitude ecosystems is the pteropod. With OA, the pteropod shell will thin because the aragonite is highly soluble. As the shell thins, it changes the mass distribution and buoyancy of the animal, which will affect locomotion and through it, all locomotion dependent behavior such as foraging, mating, predator avoidance and migratory patterns. A lower shell weight will be counterbalanced by a smaller mucus web potentially decreasing ingestion rates and carbon flux rates. This interdisciplinary research relies on biological studies of swimming behavior of the pteropod mollusk Limacina helicina in their natural environments with fluid mechanics analyses of swimming hydrodynamics via 3D tomographic particle-image velocimetry and computational fluid dynamics (CFD). This work will: (a) determine how the L. helicina uses its ?wings? (parapodia) to propel itself; (b) examine whether its locomotory kinematics provide efficient propulsion; (c) identify the factors that influence swimming trajectory and ?wobble?; and (d) synthesize all data and insights into guidelines for the potential use of pteropod swimming behavior as a bioassay for OA.

The loss of these sentinels of anthropogenic increases in CO2 may result in an ecological shift since thecosome pteropods are responsible for ingesting nearly half the primary production in the Southern Ocean and also serve as a primary food resource to upper trophic levels like fish. Since locomotory data can be gathered immediately, the bioassay being developed in this proposal may serve as an early warning of the impending onset of OA effects on this important member of the plankton. Students and researchers will collaborate in a rich interdisciplinary research environment by working with a biological oceanographer, a fluid mechanics expert and a CFD expert ? coupled with the teamsmanship needed for work in the Antarctic. By setting up a one-of-a-kind 3D tomography system for visualizing flow around planktonic organisms in Norway and at Palmer Station, we increase international exchange of state-of-the-art techniques. The educational impact of the current research will be multiplied by including in the research team, undergraduate students, high-school students and underrepresented minorities in addition to graduate students.

Person	Role
Yen, Jeannette	Investigator
Mittal, Rajat	Investigator
Webster, Donald R	Co-Investigator

Antarctic Organisms and Ecosystems	Award # 1246317
Antarctic Organisms and Ecosystems	Award # 1246296

USAP-1246317
USAP-1246296_1

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Tomographic PIV measurements of swimming shelled Antarctic pteropod	None	exist
USAP-DC	Hydrodynamics of Spongiobranchaea australis	None	exist

1. Adhikari, D., D.R. Webster, and J. Yen (2016) Portable tomographic PIV measurements of swimming shelled Antarctic pteropods. Experiments in Fluids 57: 180 (17pp). (doi:10.1007/s00348-016-2269-7)
2. Murphy, D. W., D. Adhikari, D.R. Webster, and J. Yen. "Underwater flight by the planktonic sea butterfly," Journal of Experimental Biology, v.219, 2016, p. 535-543. doi:10.1242/jeb.129205 (doi:10.1242/jeb.129205)
3. Zhang, C., Hedrick, T. L., & Mittal, R. (2019). An Integrated Study of the Aeromechanics of Hovering Flight in Perturbed Flows. AIAA Journal, 57(9), 3753–3764. (doi:10.2514/1.j056583)
4. Zhou, Z., & Mittal, R. (2017). Swimming without a spine: computational modeling and analysis of the swimming hydrodynamics of the Spanish Dancer. Bioinspiration & Biomimetics, 13(1), 015001. (doi:10.1088/1748-3190/aa9392)
5. Weissburg, M. J., Yen, J., & Fields, D. M. (2019). Phytoplankton odor modifies the response of Euphausia superba to flow. Polar Biology, 42(3), 509–516. (doi:10.1007/s00300-018-02440-w)
6. Mohaghar, M., Adhikari, D., & Webster, D. R. (2019). Characteristics of swimming shelled Antarctic pteropods (Limacina helicina antarctica) at intermediate Reynolds number regime. Physical Review Fluids, 4(11). (doi:10.1103/physrevfluids.4.111101)
7. Zhou, Z., & Mittal, R. (2020). Computational modeling of swimming in marine invertebrates with implications for soft swimming robots. Bioinspiration & Biomimetics, 15(4), 046010. (doi:10.1088/1748-3190/ab8bee)
8. Zhou, Z., & Mittal, R. (2018). Swimming performance and unique wake topology of the sea hare (Aplysia). Physical Review Fluids, 3(3). (doi:10.1103/physrevfluids.3.033102)