Friday Fellow: Red Euglene

by Piter Kehoma Boll

Don’t be as fool as the Egyptian Pharaoh in the myth of the Plagues of Egypt. If you happen to find a lake with red water, as in the picture below, it is certainly not blood. It’s simply… a toxic alga!

Sometimes one may find the waters of a like turned red. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

Sometimes one may find the waters of a lake turned red. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

The creature responsible for this coloration is today’s Friday Fellow: Euglena sanguinea, or the red euglene, a microscopic freshwater protist with a worldwide distribution. This unicellular organisms has a red color due to the presence of astaxanthin, a pigment also found in some fish, like salmon, and in crustaceans, like shrimp and crayfish. Some birds may also have this pigment in their feathers. In red euglenes, astaxanthin acts as a protection against ultraviolet radiation, so that the higher the amount of UV radiation, the redder the algae become.

A fraction of a population of red euglenes under the microscope. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

A fraction of a population of red euglenes under the microscope. Photo extracted from naturamediterranea.com/forum/, posted by user Carlmor.

When the conditions are adequate, usually due to high temperatures and high amounts of nutrients, the red euglene may overpopulate and cover the entire surface of water bodies, making it appear red. Water pollution, especially from domestic wastewater, is one of the main causes of nutrient increase in water bodies and thus a direct cause of many algal blooms.

The red euglene is known to produce euglenophycin, a very potent ichthyotoxin, i.e., a compound that is toxic to fish. As a result, red euglene blooms can lead to high fish mortality, making it an organism of major concern to fish breeders.

– – –

References:

Gerber, S.; Häder, D-P. 2006. Effects of enhanced UV-B radiation on the red coloured freshwater flagellate Euglena sanguineaFEMS Microbiology Ecology, 13(3): 177-184. DOI: 10.1111/j.1574-6941.1994.tb00064.x

Wikipedia. Euglena sanguinea. Available at <https://en.wikipedia.org/wiki/Euglena_sanguinea&gt;. Access on  January 07, 2016.

Zimba, P. V.; Rowan, M.; Triemer, R. 2004. Identification of euglenoid algae that produce ichthyotoxin(s). Journal of Fish Diseases, 27: 115-117.

Advertisements

Leave a comment

Filed under Algae, Conservation, Ecology, Friday Fellow, Pollution

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s