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74 | Red Seaweeds

Red Seaweeds

Red seaweeds make up the majority of seaweed species, with more than 7,000 species now recognized worldwide (up from roughly 5,500 at the time of the original Pacific Seaweeds). Approximately 400 of the 600 or so seaweed species noted for our survey area are red seaweeds. These seaweeds vary morphologically from simple filaments to intricate, fleshy plants. Their most elaborate form is expressed as dorsal-ventrality, or having a distinguishable front and back. Here we present 121 species representing the diversity in our area.

“Red” algae can appear greenish, yellowish, brownish, red (including pink) or purple. Red, their basic colour, is the result of the dominant pigment phy-coerythrin (Greek=algal red) and associated phycocyanin (Greek=algal blue). When this pigment complex is destroyed or diminished by stressful conditions of intense light, high temperature and/or low nutrients, the masked pigments responsible for green and brownish colouration are expressed, thus giving the seaweed an off colour. At first this may cause confusion in identifying a sea-

A cacophony of red seaweed species appears at low tide.