The role of phytoplankton morphology on dominance under different turbulent regimes

  • Russell Arnott

Student thesis: Doctoral ThesisPhD


In the last forty years, harmful algal blooms (HABs) have increased in frequency, severity and distribution (Hallegraeff, 2010). As well posing a health risk to humans and aquatic organisms alike, HABs have a direct economic impact on drinking water, bathing water, tourism and fisheries with the loss of earnings and subsequent amelioration reaching billions of dollars globally (Smith et al., 2019; Sakamoto et al., 2021). While eutrophication and increasing global sea surface temperatures associated with climate change are thought be major drivers of this HAB increase, more subtle interactions between phytoplankton cells and their physical environment can also play a role in determining whether a bloom of a specific species occurs.

The overall aim of this project of this project is to ascertain to what extent morphology of the phytoplankton species studied dictates how they become dominant under different turbulent regimes. At present, there is some discrepancy between the output predictions of different ecological models and observations in the natural environment. It is hoped that this project will be able to, in part, account for these discrepancies thus improving future models. Further understanding of how turbulence and phytoplankton morphology influence resultant phytoplankton community and HAB distributions may contribute considerably to enhanced lake and reservoir management and general water quality awareness.

Initially conceived with a view of refining the marine ecosystem model developed by Portalier et al. (2016), this research aims to increase the accuracy of predator-prey interactions within the model by accounting for turbulent processes. These processes originally focussed on turbulence as a means by which to influence predator-prey contact rates; here, I aim to facilitate the inclusion of turbulence effects as a key factor influencing the dominance of different groups of phytoplankton.

This project also aims to continue to build a bridge between the realm of physical turbulence measurements and marine microbiology. While Peters and Redondo (1997) report a steep increase in the number of turbulence-phytoplankton interaction studies, there is still a tendency within the scientific community to work within carefully defined disciplinary spheres with biologists not fully appreciating the influence that turbulence can have on organisms and aquatic physicists overly simplifying biological interactions.
Date of Award25 May 2022
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorLee Bryant (Supervisor), Danielle Wain (Supervisor), Mehdi Cherif (Supervisor) & Chris Blenkinsopp (Supervisor)


  • turbulence
  • phytoplankton

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