Brown algae, also known as kelps, are a group of seaweeds in the order Phaeophyta. They attach to rocks on the sea bottom by a tissue known as their holdfast, from which their flexible stems (known as a stipe) and leaf-like tissue (or fronds) grow into the water column. In some species, the fronds are kept buoyant by gas-filled bladders. Kelp tissues are extremely tough only the strongest storms are capable of tearing their fronds or ripping their holdfasts from the rocky bottom. When this happens, however, large masses of kelp biomass can float around as debris known as "paddies," or wash onto the shore as "wrack."

In some temperate marine habitats, large species of brown algae can be extremely abundant. These ecosystems are known as kelp forests. Because they are extremely productive ecosystems, and have a great deal of physical structure...