https://doi.org/10.1140/epje/i2019-11792-0
Topical Review
Gyrotactic phytoplankton in laminar and turbulent flows: A dynamical systems approach
1
Istituto dei Sistemi Complessi, CNR, via dei Taurini 19, 00185, Roma, Italy
2
INFN Tor Vergata, via della Ricerca Scientifica 1, 00133, Roma, Italy
3
Dipartimento di Fisica and INFN, Università di Torino, via P. Giuria 1, 10125, Torino, Italy
* e-mail: filippo.delillo@unito.it
Received:
13
April
2018
Accepted:
8
February
2019
Published online:
20
March
2019
Gyrotactic algae are bottom heavy, motile cells whose swimming direction is determined by a balance between a buoyancy torque directing them upwards and fluid velocity gradients. Gyrotaxis has, in recent years, become a paradigmatic model for phytoplankton motility in flows. The essential attractiveness of this peculiar form of motility is the availability of a mechanistic description which, despite its simplicity, revealed predictive, rich in phenomenology, easily complemented to include the effects of shape, feedback on the fluid and stochasticity (e.g., in cell orientation). In this review we consider recent theoretical, numerical and experimental results to discuss how, depending on flow properties, gyrotaxis can produce inhomogeneous phytoplankton distributions on a wide range of scales, from millimeters to kilometers, in both laminar and turbulent flows. In particular, we focus on the phenomenon of gyrotactic trapping in nonlinear shear flows and in fractal clustering in turbulent flows. We shall demonstrate the usefulness of ideas and tools borrowed from dynamical systems theory in explaining and interpreting these phenomena.
Key words: Topical issue: Flowing Matter, Problems and Applications
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2019