Algae

Algae are simple plants that grow mostly in water.  Many fish feed on algae.  Pollution can cause algae to  multiply.  A single algae is called an alga.  Some algae are microscopic!!

Blue-Green Algae

Some kinds of blue-green algae form slippery, dark, coatings on rocks along the shores of rivers, lakes, and oceans.  A few species of blue-green algae may poison fish, cattle, and other animals that drink water consisting of these organisms.

Brown Algae

There are a lot of Brown Algae along the seashores in temperate zones.  Algin, a gummy substance obtained from kelp, is used to thicken cosmetics, ice cream, mayonnaise, and other products.  Some types of  brown algae were once widely used as fertilizer and a source of iodine.

Green Algae

Green Algae can grow in freshwater and saltwater.  A lot of Green Algae are microscopic and grows in lakes, ponds, and streams.  Some scientists are experimenting with growing Green Algae for food, but most algae don't have high food value.

Red Algae

Red Algae are mostly found in subtropical seas.  Red Algae can sometimes grow with coral and a few species live in freshwater. Some Red Algae have blue as well as green and red pigments.   Japanese people eat a red algae that they call nori.  It is usually sold as dry as paper.