Ethological dynamics in diorama environments

Planktonic foraminifera are planktonic organisms that float in the ocean while forming a heavy shell (test) made of calcium carbonate. In addition to morphological features such as long spines, planktonic foraminifera can extend and reticulate their pseudopods outside their tests, and it is assumed that they adapt to floating life by increasing resistance to seawater. However, whether such floating mechanisms work has not been verified experimentally or theoretically. In this study, I focus on both the "non-sinking mechanism" by cellular behavior and the “buoyant mechanism" by intracellular components to understand the floating strategy of marine testate protists. Specifically, I aim to clarify what makes planktonic foraminifera planktonic by combining vertical migration experiments in a diorama environment, intracellular observations, and theoretical models.