Average chlorophyll concentration in the surface ocean (from mi-September 1997 to August 2007) from the ocean color sensor SeaWiFS (NASA). Subtropical gyres, in the center of the oceanic basins, are characterized by very low concentrations of chlorophyll a (dark blue) - Source : NASA's Earth Observatory (http:/earthobservatory.nasa.gov)
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 fusus (Photo : Sophie Marro)
