The giant green anemone (Anthopleura xanthogrammica) in which the unicellular Elliptochloris sp. resides.
Green Seaweeds | 73
Identifying Pacific Seaweeds
Description
These plants are microscopic but can be dense enough in number to appear as a green stain on shells and rocks. The most eagle-eyed of read-ers may detect these minute plants as green dots within bladed red seaweeds such as Mazzaella (p. 127) and Mastocarpus (p. 112).
Habitat & Distribution
‘Codiolum’ and ‘Chlorochytrium’ inhabit bladed and crusty red seaweeds, as well as calcareous structures such as rocks and the shells of bar-nacles and mussels.
A rock stained green by the presence of many ‘Codiolum’ or ‘Chlorochytrium’ unicells.
Left: ‘Codiolum’. Right: Cross-section of Schizymenia showing positioning of ‘Chlorochytrium’ (c). RFSG
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.
Red Seaweeds | 75
Identifying Pacific Seaweeds
weed, but once you become familiar with the basic forms of red, green and brown seaweeds, colour will not be so important. Off-colour reds often have a little of their true colour near the point of attachment. Also, because of their unique intercellular connections, red seaweeds have a rubbery elasticity not found in other seaweeds. You can feel this by gently tugging a fleshy individ-ual, also known as the “boingy-boingy test.”