Red seaweed (maybe Agardheilla sp). 40x magnification. Darkfield microscopy.

Rhodophyta (red algae) is the largest phylum of algae with most members organisms being multicellular and living in marine environments, just like the organism in this photo. The ancestors of the rhodophytes are among the oldest known algae. In fact, fossils of red algae have been found that date back over one billion years!Red algae plays a bigger role in our day to day lives than you might think. It is the seaweed (nori) used in sushi and it is also used as a thickening agent (agar) in some ice creams! This agar is also the substance used in microbiology and biotechnology applications, for example, to make PCR and Western blot gels to run experiments on DNA, RNA, and proteins.