Going ballistic in the plankton: anisotropic swimming behavior of marine protists

Schuech, Rudi and Menden-Deuer, Susanne (2014) Going ballistic in the plankton: anisotropic swimming behavior of marine protists. Limnology and Oceanography: Fluids and Environments, 4 (1). pp. 1-16. ISSN 2157-3689

Full content URL: http://dx.doi.org/10.1215/21573689-2647998

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Item Type:Article
Item Status:Live Archive


Diel vertical migrations (DVMs) of many plankton species, including single-celled protists, are well documented in the field and form a core component of many large-scale numerical models of plankton transport and ecology. However, the sparse quantitative data available describing motility behaviors of individual protists have frequently indicated that motility exhibits only short-term correlation on the order of a few seconds or hundreds of micrometers, resembling diffusive transport at larger scales—a result incompatible with DVM, which requires ballistic (straight-line) motion. We interrogated an extensive set of three-dimensional protistan movement trajectories in an effort to identify spatial and temporal correlation scales. Whereas the horizontal components of movement were diffusive, the vertical component remained highly correlated (i.e., nonrandom) for nearly all species for the duration of observation (up to 120 s and 6.1 mm) and in the absence of any environmental cues besides gravity. These persistent motility patterns may have been obscured in some previous studies due to the use of restrictive containers, dimensionally lumped, isotropic analyses, and/or an observation bias, inherent to observing free-swimming organisms with stationary cameras, which we accounted for in this study. Extrapolated over a 12-h period, conservative estimates of vertical travel ranges for the protists observed here would be 3–10 m, while diffusive horizontal motion would result in about 10 cm of travel at most. Hence, these extended observations of phylogenetically diverse swimming protists, coupled with a quantitative analysis that accounts for anisotropy in the data, illustrate the small-scale mechanistic underpinnings of DVM.

Keywords:plankton, diffusion, motility, correlation, migration, JCOpen
Subjects:C Biological Sciences > C160 Marine/Freshwater Biology
Divisions:College of Science
ID Code:16658
Deposited On:08 Feb 2015 20:24

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