Pelagia - Fearsome Jellyfish
Mauve jellies move in droves, their nasty stings feared by swimmers.

Diatoms - Life in glass houses
Champions of photosynthesis, these unicellular organisms appeared at the time of dinosaurs.They produce a quarter of the oxygen we breathe.

The Glider

The seasonal evolution of the chlorophyll a concentration as seen by a « water color » satellite (SeaWifs) in the Atlantic Ocean.

Siphonophores - The longest animals on the planet
Cousins of corals, siphonophores are colonies of specialized individuals called zoids. Some catch and digest their prey, others swim, or lay eggs or sperm.

Dinoflagellate Ceratium gravidum. In the video one can observe the movement of one of the two flagella. (Video : Sophie Marro)