Sugar kelp is a common kelp seaweed found in shallow seas around our coasts. It grows attached to rocky seabeds using root-like holdfasts. It grows at depths up to 30m and are found mainly on sheltered shores, including in deep rockpools. Unlike other kelp seaweeds, Sugar kelp has one long ribbon like frond on a short thin stipe (like a stem). This long, wide frond is crinkled throughout and gives the seaweed its other name of Sea belt. The short stipe is very flexible so that it bends and keeps the frond submerged in shallow water to prevent it from drying out on low tides. Sugar kelp grows particularly quickly in early spring and gets its name from the sweet white powder (mannitol) that comes to the surface as the seaweed dries.
How to identify
Sugar kelp is a large 'kelp' seaweed, dark browny-green, with a single broad frond that has a distinctive crinkly and wavy edge.
Distribution
Common on rocky shores all around our coasts.
Did you know?
Sugar kelp was once used to give a weather forecast! Dried fronds would be hung outside and used to predict the weather using the air humidity. If the frond stayed dry, the day would be fine; if it softened and went limp, rain was on the way. This gives it another common name of Poor Man's Weather Glass!
