(Spiruline, Chlorella, Algues bleu vert, Algues brunes)
Generally, you make the difference between macro and micro algae as follows:
Macro algae are multicellular marine algae which form a real plant. They have a stem and leaves. Depending on water depth they are brawn, red or green.
Marine algae stick with their root on rock and are completely rinsed from sea water. They are 4000 different marine algae but only a few suitable for human consumption. Algae contain valuable nutrients, among others lots of trace elements including one very important: iodine. Another essential element is algin used in various matters especially in food production.
Macro algae are different.
They are one cell algae. Spirulina, Chlorella or also blue green algae are very popular in this variety. They are cultivated in fresh water tanks. The "algae bloom" which is driving at certain seasons in coastal regions is also one of the microalgae.