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Red Algae

Several thousand species of red algae have been identified and are classified together in the division Rhodophyta. Most are multicellular marine varieties that predominantly inhabit tropical and subtropical areas, though some are unicellular and prefer different habitats.

Red Algae

The color of red algae, which is sometimes blue rather than red, is due to the presence of phycobilin pigments. These accessory pigments aid in photosynthesis and mask the green chlorophyll pigments also present in the algae. The life cycle of red algae is complex, and the majority of rhodophytes reproduce sexually. Both male and female gametes are nonmotile.

Red algae are important in a number of ways. Some varieties known as coralline algae secrete calcium carbonate and are heavily involved in the building of tropical reefs. Other rhodophytes are commercially valuable, especially in the food industry. In traditional Asian cuisine, for instance, Porphyra species (commonly referred to as nori) are often incorporated into dishes. Other types of red algae are used in products such as ice cream and pudding as an alternative to gelatin. Red algae products can also be found in the laboratory; the agar that frequently serves as a culture medium is derived from several different types of red algae.

Contributing Authors

Nathan S. Claxton, Shannon H. Neaves, and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.