Coccolithophore bloom in the Celtic Sea
September 14, 2000
What, you might ask, are coccolithophores? They're microscopic sea organisms, a kind of phytoplankton. They may be small, but they can occur in outbreaks the size of entire countries. The light blue-green patches you see off the coast of England and Ireland are blooms of one particular species, E. huxleyi.
Coccolithophores are unique because of the scales, or coccoliths, that they shed. These tiny scales stay suspended in the water and reflect light back into space, much like what would happen if you stirred glitter or sequins into the water. This is how the SeaWiFS satellite was able to detect them in this image taken May 18, 1998. (A similar outbreak appeared in the same place a year later, not likely due to the luck of the Irish.)
We don't know why coccolithophores bloom like this, or how they affect the marine ecosystem. But now that we have satellites to map the outbreaks, we are better able to study them and determine their causes and effects. If it weren't for coccolithophores and their relatives, some of the land in this image wouldn't exist: the famous white cliffs of Dover, England, are composed of the calcium carbonate skeletons of ancient phytoplankton that were once swimming in the sea like these.