The name plankton is derived from the Greek adjective πλαγκτός (planktos), meaning errant, and by extension, wanderer or drifter,^[5] and was coined by Victor Hensen in 1887.^[6][7] While some forms are capable of independent movement and can swim hundreds of meters vertically in a single day (a behavior called diel vertical migration), their horizontal position is primarily determined by the surrounding water movement, and plankton typically flow with ocean currents. This is in contrast to nekton organisms, such as fish, squid and marine mammals, which can swim against the ambient flow and control their position in the environment.