This is a culture flask being shaken in front of a video camera. The dark whorls are actually light backscattering off elongated microbes locally aligned with the turbulent flow. Video / Marcos, Seymour, Luhar, Durham, Mitchell, Macke and Stocker from the paper, "Microbial alignment in flow changes ocean light climate," PNAS Early Online Edition, Feb. 21, 2011. Read a news story about this at http://cee.mit.edu/news/releases/2011/microbial-alignment