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Red euglena

Euglena sanguinea


Euglenoids are solitary cells that have characteristics of both animals (movement and ingestion of nourishment) and plants (chloroplasts). The red pigment helps protect the cells from light that is too intense and then makes the water look red.


Pond in local nature reserve


The red euglena can turn green as well and then it may look as if it is no longer in the pond. It can be an indicator of organic pollution.

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Maria dB
Maria dB 10 months ago

Well, thanks for the nomination, Mark! It is an unusual organism. When I first spotted it, I saw birds drinking from the water and wondered if they would get sick but that does not appear to have happened. I guess the red color makes it look like it might have contaminated the water.

Mark Ridgway
Mark Ridgway 10 months ago

Your spotting has been nominated for the Spotting of the Week. The winner will be chosen by the Project Noah Rangers based on a combination of factors including: uniqueness of the shot, status of the organism (for example, rare or endangered), quality of the information provided in the habitat and description sections. There is a subjective element, of course; the spotting with the highest number of Ranger votes is chosen. Congratulations on being nominated!

Mark Ridgway
Mark Ridgway 10 months ago

Weird and wonderful.

Leuba Ridgway
Leuba Ridgway 11 months ago

Good to know Maria. Thanks.

Maria dB
Maria dB 11 months ago

Hi, Leuba! I have looked online to see if there is a connection but it appears they are just different species of Euglena. Encyclopedia Britannica comments: "Some species, especially E. viridis and E. sanguinea, can develop large toxic populations of green or red “blooms” in ponds or lakes with high nitrogen content." So perhaps they just share that characteristic in contrast to some other species. Thanks for your comment!

Leuba Ridgway
Leuba Ridgway 11 months ago

I've only ever heard of Euglena viridis. Is there any connection between E.vridis and the green form of E.sanguinea- do you know?
Apparently E.viridis at times form a green film on ponds.
Interesting spotting Maria.

Maria dB
Spotted by
Maria dB

North Carolina, USA

Spotted on Nov 28, 2019
Submitted on Jan 26, 2020

Spotted for Mission

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