Algae Strains - Not All Algae is Green

Algae is supposed to be green and slimy right?

All algae contain chlorophyll. But, not all algae is green.

Some algae have pigments that mask the green chlorophyll.  Algae exhibits different color variations because of the other photosynthetic pigments they contain.  

The major algae divisions can, for the most part, be drawn based on the algae's predominant apparent color.  

Here's a brief, "back of napkin" look at the various algae strains:

Chromista

The chromista algae contain almost exclusively marine algae and include brown algae, golden brown algae, and diatoms.

These types of algae have plastids that contain chlorophylls A and C. Brown algae is the largest of the algae types – the largest brown algae can reach over 30 meters long.

Brown algae are the source of alginate, a widely used substance valued mainly for its gelling properties.

Red Line

The red line algae is an early branch of marine algae and has plastids that contain only one chlorophyll type - chlorophyll A. The pigment phycoerythrin , a pigment that reflects red light and absorbs blue light, is responsible for this algae's red color. As you'll see in this article, other algae branches have two types of chlorophyll. 

Red line algae are the algae type that one often sees coating the wave-washed rocks along a beach and some types of red algae are also responsible for helping create many of the world's tropical reefs.

These reef-building algae types are called "coralline algae". In addition, some red line algae - which is rich in vitamins and minerals, including B vitamins and iron - serve as an important food source in Asian countries.

If you've ever eaten nori, you've eaten red algae!

Red algae are also where we get agar, a gelatinous substance that has many uses. A common use is in the scientific field, where it's used as a medium in which to suspend bacteria or other microorganisms.

Agar is particularly useful in this instance because most microorganisms are unable to digest agar. Carrageenan is another example of a substance derived from red algae and used in food.

Carrageenan is a stabilizer and can be found in milk products.

Dinoflagellates

 Dinoflagellates are unicellular organisms with many variations of form. Some dinoflagellates are capable of producing their own light through a process called bioluminescence – the same process that makes fireflies glow. Others are food sources for animals, and still others are parasites on fish or other types of protists.

One of the most obvious and dramatic effects of dinoflagellates comes from the marine species of this type of algae. It is responsible for what is called an algal “bloom”, which happens during the warm summer months when the algae are rapidly reproducing.

This causes what is commonly known as a red tide, which is called such because the water may appear to be golden or red due to the high amount of algae. 

Euglenids

There are ver 1400 known types of Euglenids, the single-celled organisms that are part of an independent line of algae. They include both the photosynthetic and the non-photosynthetic species.

Most Euglenids are found in freshwater, with just a few marine types.

Green Line

The green line of algae is the most diverse, containing over 7000 species of algae that grow in a wide variety of habitats.

Green algae is related to plants - both this algae branch and plants have chlorophylls A and B.

The green line of algae is classified as algae and not as a plant because it is aquatic and creates its own food.

Many types of algae form symbiotic relationships with other organisms. Green algae can be found living near the surface of some sea sponges.

This protects the algae from predators while providing the sea sponge with oxygen and sugars which help the sponge's growth.

What's your favorite type of Algae?