Production in the autumn dependslargely on which comes first: the shortdays and weak sunlight that bring lightlimitation, or surface cooling and storms, which increase the mixing of nutrients. If the days are cool and sunny, for example,a strong wind can mix up nutrients whilethe phytoplankton still have enough lightto perform photosynthesis. If so, there will be a burst of production known asthe
fall bloom
(Fig. 15.28
b
). If warm,mild conditions persist late into the fall