Largest alga
giant kelp Macrocystis pyrifera
60 metre(s)
Not Applicable ()

The largest species of alga is the giant kelp Macrocystis pyrifera, a species of seaweed belonging to the taxonomic class Phaeophyceae, the brown algae. The longest verified specimen attained a total length of 60 m. However, there are unverified records of even longer specimens. It lives near rocky shores in the Pacific Ocean.

This giant species of kelp can grow up to 60 cm per day, which constitutes a growth speed of almost 3 cm per hour, and it can reach its total, maximum length of 40–60 m in a single growing season. Indeed, it is the fastest growing marine plant on Earth.