The Effects of Jellyfish Motion of Stratified Layers (2016)

Undergraduate: Grace McLaughlin

Faculty Advisor: Laura Miller
Department: Biology

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My research was conducted around the question of whether or not jellyfish contribute to ocean mixing. This is something that is of interest to many scientists around the world because the better we understand how our ocean's waters circulate, the better we can predict how they will behave in the future. In addition to this, studying how jellyfish interact with fluid helps to understand their overall role in the ocean's ecosystem. I have been looking specifically at how two species of jellyfish, upside down jellyfish (Cassiopea) and moon jellyfish (Aurelia aurita), mix stratified layers of different densities. I did this by first making the layers and marking one of them with fluorescent dye and then allowing the jellyfish to mix the water. Qualitative information was gathered as the dye was observed to mix, and quantitative data was obtained by using a conductivity probe to measure density/salinity changes. The second part of my research involved using a PIV laser system to analyze how the jellyfish mixed the fluid. Significant mixing was observed compared with tanks that did not have the jellyfish present, although the moon jellyfish demonstrated some reluctance to move through a density layer.