Artificially generated turbulence: A review of phycological nanocosm, microcosm, and mesocosm experiments

Building on a summary of how turbulence influences biological systems, we reviewed key phytoplankton-turbulence laboratory experiments (after Peters and Redondo (1997) and Peters and Marrasé (2000)) to provide a current overview of artificial-turbulence generation methods and quantification techniques. This review found that most phytoplankton studies using artificial turbulence feature some form of quantification of turbulence; it is recommended to use turbulent dissipation rates (ε) for consistency with physical oceanographic and limnological observations. Grid-generated turbulence is the dominant method used to generate artificial turbulence with most experiments providing quantified ε values. Couette cylinders are also commonly used due to the ease of quantification, albeit as shear rates not ε. Dinoflagellates were the primary phytoplanktonic group studied due to their propensity for forming harmful algal blooms (HAB) as well as their apparent sensitivity to turbulence. This study found that a majority of experimental set-ups are made from acrylate plastics that could emit toxins as these materials degrade under UV light. Furthermore, most cosm systems studied were not sufficiently large to accommodate the full range of turbulent length scales, omitting larger vertical overturns. Recognising that phytoplankton-turbulence interactions are extremely complex, the continued promotion of more interdisciplinary studies is recommended.