Fun Fact

At the very base of the food chain is plant plankton, these microscopic single- or multicellular algae with sometimes impressive shapes. The change in color of the water and the visible proliferation of algae occurs when these microscopic units have reached a sufficiently high concentration. These will then feed the animal plankton, composed largely of mollusc larvae (mussels and shellfish), crustaceans (shrimp, crabs) and others (sea urchins, corals, jellyfish). However, some planktonic animals spend their lives at the microscopic stage, such as daphnia and copepods. You will easily see them swarming in the stagnant water of a pond when they are illuminated by a ray of sunlight. These will then feed the fish, ducks or even whales.

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In abnormal proportions, algal blooms can have a harmful effect on the environment, by clouding the water and depleting it of oxygen, leading to an increase in its temperature. This abnormal bloom is often due to excess nitrogen or phosphate, from products that we use in agriculture or in our households, such as in detergents. While the use of phosphates in detergents is now limited in the EU, the massive use of nitrogen fertilisers in agriculture and their path to lakes and seas is still a major controversy.

Riddle

What proportion of atmospheric oxygen comes from plant plankton?

A) None, it stays in the water

B) 25%, it's so small after all

C) 50%

D) 66%, almost as much as the surface area covered by water on earth