The diurnal vertical migration of motile phytoplankton through temperature gradients1

In experiments in a 10 m, thermally stratified seawater column, Cachonina niei crossed a 5°C gradient during a 4‐m diurnal vertical migration, while Amphidinium carteri remained in the upper, isothermal, part of the water column during a 1‐m diurnal vertical migration. The experiments confirm that some marine dinoflagellates have access to subthermocline nutrient pools. These same species may also exhibit spatial and temporal patchiness in response to countercurrent flow across the thermocline.