Chemical mediation of macroalgal-herbivore interactions: Ecological and evolutionary perspectives

This chapter considers interactions between herbivores and benthic marine algae and seagrasses. It also discusses benthic cyanobacteria because many species are large, conspicuous, and common components of tropical communities, and recent studies suggest that their role is similar to that of true algae in coral reefs. The term “seaweeds” traditionally includes the macroscopic, multicellular, marine green, brown, and red algae; the benthic, filamentous blue-green algae are also sometimes considered. All seaweeds are unicellular at some stage of their life cycle (usually as spores or zygotes), and they are viewed as “primitive” photosynthetic organisms because of their simple construction and reproduction. There is a wide variation in algal classification among systematists, but the traditional divisions for algae are the Cyanobacteria (prokaryotic blue-green algae, sometimes termed Cyanophyta), Chlorophyta (green algae), Phaeophyta (brown algae), and Rhodophyta (red algae). The seagrasses are the only truly submerged angiosperms in the marine environment.