Most of the organisms living in the oceans are tiny, but they have a big effect on ocean mixing, according to a new study in Nature. Bioengineers from CalTech investigated this effect in Palau by adding a fluorescent dye to water near jellyfish to see what would happen when the jellies swam through. To the scientists' surprise, the dye traveled along with the jellyfish for long distances. Jellyfish and other marine organisms regularly migrate to the ocean surface during the day. Extrapolating from their experiment, the bioengineers calculated that the amount of mixing from this migration is as much as a trillion watts of energy, about equivalent to the effects of the winds and tides.