The authors fail to explain a necessity for their device. Within the text there was no mention of any relevant, previous research which could have utilized such a device. There was no mention of plankton motility studies. Additionally, the methods and device set-up description were quite vague. The capabilities and limitations of the device were poorly described as well.
In short, from what was provided in the text, I could not understand how the device is relevant for plankton studies.