12 Photosynthetic Stramenopiles I

Introduction and Diatoms

In contrast to the leafy green environment experienced by humans, many other organisms occupy a predominantly brown or golden-brown world. A brown canopy of giant kelps shelters sea otters, urchins, many kinds of fish, and other inhabitants of kelp forests. Bushy thickets of brown Turbinaria seaweed growing on tropical reefs are favored by the dinoflagellate Gambierdiscus. Other microscopic organisms live within films of golden diatoms growing on shoreline rocks of diverse aquatic habitats. Such brown seaweeds, golden-brown diatoms, and similarly pigmented relatives are classified together with several clades of heterotrophic protists into the supergroup Stramenopila. This chapter begins with an overview of the photosynthetic stramenopiles and then focuses on the diatoms. Additional groups of photosynthetic stramenopiles are the subjects of Chapters 13 and 14.