1. Occurrence and Importance
Marine macroalgae are important biological components of Earth’s oceans and are found in coastal and intertidal zones in depths where light penetration is sufficient for photosynthesis. They are classified in 1 of 3 phyla, which are named according to the color derived from major photosynthetic pigments present in their members. Members of Chlorophyta (green algae) contain chlorophyll a and b and ß-carotene. The red algae (Rhodophyta) contain phycoerythrin, an accessory pigment that provides the reddish color observed in most species of this phylum. The brown algae (Phaeophyta) contain the brown accessory pigment fucoxanthin. Within this phylum are the most structurally complex of all algae, the laminarians (Order Laminariales). Laminarians include the large, canopy-forming kelps of the world, such as the giant kelp Macrocystis pyrifera.
Macrocystis pyrifera (see Section 10900, Plate 2A:E) forms extensive coastal submarine forests that provide food, habitat, and shelter for numerous species.1 The giant kelp also is an important economic resource that is harvested commercially to obtain alginic acid, a thickening agent used in foods, cosmetics, culture media, and other products.
Therefore, it is an attractive test species for monitoring coastal water quality. Indeed, test methods using the early life stages of giant kelp have been developed and found to be sensitive to many toxicants found in the coastal environment.2–4 The Macrocystis pyrifera method has been used successfully in National Pollution Discharge Elimination System (NPDES) monitoring and compliance programs in California and other regions along the Pacific Coast of North America since 1990.5