Diapositiva PPT
The spring bloom at mid-latitudes:
- In winter, there is convective mixing down to a deep thermocline. Phytoplankton is transported up and down: very few time at the photic layer Ŝ low productivity.
- In spring, with the stablishment of a shallower thermocline, phytoplankton most of the time at the photic layer (+ increased luminosity) Ŝ explosive growth: the bloom
- After some time, zooplankton grows and grazes phytoplankton (zooplankton bloom). Later, nutrients become depleted, and phytoplankton scarce. The bloom dies.
- In autumn, with the destruction of the shallow thermocline, convective mixing brings nutrients to the photic layer Ŝ smaller autumn bloom.