What is Brown Algae ?
Phaeophyta are commonly known as brown algae; precisely because they are - guess what? - brown in color! They are brown because they contain brown colored pigments, such as fucoxanthin, in addition to green chlorophyll to help in photosynthesis.
Brown algae are among some of the most common seaweeds, and are abundant almost everywhere along the temperate coastal areas of the world. Some of the larger brown algae form underwater kelp "forests," which are actually farmed and harvested for products extracted from their cell walls. The kelps that form these forests, such as Macrocystis shown below, grow rapidly and can reach over 100 meters in length. Like any other forest, the kelp forests, along with their accompanying marine invertebrates, fish, birds and marine mammals, make up unique and interesting ecosystems.