Foam algae (Phytoplankton)

Phytoplankton is a very diverse group of tiny unicellular or colony-forming algae that can be carried along by the ocean currents. They are so small that they are not visible to the naked eye. Only when they develop en masse do they become visible in the water as algal blooms. Like plants, these algae carry out photosynthesis, converting carbon dioxide into 'body mass' with the help of sunlight.

When colonies of foam algae die, the waves whip up the slime shell in a strong wind, creating foam - you can best compare this to whipping egg whites to make whipped cream. This foam later washes up on the beaches, sometimes in massive quantities.

Although harmless in itself, the death of large quantities of foam algae does the sea no good. It can lead to a temporary lack of oxygen in the water. Dead organic material (such as algae) is broken down by bacteria, for which the bacteria use oxygen. The more algae they have to break down, the more oxygen they will consume.