Characteristics of Algae
You may have seen the green scum on the surface of a pond or the green film on the sides of an aquarium. If you have ever visited the ocean, you may also have seen seaweed washed up on the beach. Both this green scum and seaweed are algae. Algae can be both unicellular, form colonies, or be multicellular. They also can use the process of photosynthesis to produce their own food because they all contain chlorophyll in their cells.
Algae is classified into five main divisions: green algae, brown algae, red algae, diatoms, and dinoflagellates. Here are the characteristics of each of these types of algae.
Green Algae
- Live in both fresh and salt water.
- Many exist as long filaments, or strings.
- Produce most of the oxygen we breath.
- Some species pollute public water systems by poisoning the water and producing a foul smell.
Brown Algae
- Live only in salt water.
- Color results from combination of green and brown pigments.
- Represent the largest species of algae.
- Used as food.
- Produce algin, a gummy substance used in making cosmetics and ice cream.
Red Algae
- Live only in salt water.
- Color results from combination of blue, red, and green pigments.
- Used as food.
- Produce carrageen, a thickener used in ice cream and pudding.
Diatoms
- Live in both fresh and salt water.
- Have glassy cell walls, which form a two-part shell that fits together like two halves of a Petri dish.
- Form the base of the marine food chain.
- Large deposits of diatomaceous earth found in many places were formed from the remains of diatoms.
- Used to make cleansers, pool filters, and toothpaste.
Dinoflagellates
- Live only in salt water.
- Have two flagella: one for locomotion and one for steering.
- Often appear red.
- Some release toxins into the water, causing a "red tide" that often kills large numbers of fish and other marine life.