Red Algae Profiles

Saltwater, Marine, and Calcified Red Algae Properties

The Rhodophyta (red algae) are a distinct eukaryotic lineage characterized by the accessory photosynthetic pigments phycoerythrin, phycocyanin and allophycocyanins arranged in phycobilisomes, and the absence of flagella and centrioles. This is a large assemblage of between 2,500 and 6,000 species in about 670 largely marine genera that predominate along the coastal and continental shelf areas of tropical, temperate and cold-water regions. Red Algae are ecologically significant as primary producers, providers of structural habitat for other marine organisms, and their important role in the primary establishment and maintenance of coral reefs. Some red algae are economically important as providers of food and gels. For this reason, extensive farming and natural harvest of red algae occurs in numerous areas of the world.

Red marine algae have been a valued food in Asia for thousands of years due to its highly nutritious qualities. Carrageenans, a family of polysaccharide compounds extracted from algae, have been studied for their unique properties. In vitro studies show that carrageenans aid in a cell's natural defense by significantly minimizing the binding of unfriendly proteins to the cell's surface.

Among the algae that can invade freshwater ponds and aquaria, red algae from the division Rhodophyta can be the most frustrating. This furry, thread-like flora attaches to various aquarium surfaces including the edges of plant leaves, filter tubes and even gravel. It may have many colors (purple, gray-green, black) and resembles beard hair or fur.

In Asia, rhodophytes are important sources of food, such as nori. The high vitamin and protein content of this food makes it attractive, as does the relative simplicity of cultivation, which began in Japan more than 300 years ago. Some rhodophytes are also important in the formation of tropical reefs, an activity with which they have been involved for millions of years; in some Pacific atolls, red algae have contributed far more to reef structure than other organisms, even more than corals.

Red algae have a number of general characteristics that in combination distinguish them from other eukaryotic groups:

• Absence of flagella and centrioles.
• Floridean starch as a storage product and the storage of starch in the cytoplasm.
• Phycoerythrin, phycocyanin, and allophycocyanin as accessory pigments.
• Unstacked thylakoids in plastids.
• No chloroplast endoplasmic reticulum.

Preventing and Eliminating Red Algae:

The principle methods are: pre-treatment of plants with bleach, reduction of water column nutrients, algae eating animals and copper algicide.