Seaweed

Seaweed is a colloquial term that loosely embraces about 10,000 species of water plants. While all seaweeds are algae, not all algae are seaweeds – as one would assume from the name, seaweed only grows in salt water. Seaweeds need light to drive photosynthesis and most require a firm attachment point or holdfast, so they commonly proliferate on rocky shorelines or in rock pools. They are categorised by colour; green seaweed grows at the shallowest point, brown grows at depths of up to 75 ft, while red grows the deepest, up to 880 ft below sea level in clear waters. All come in different shapes and sizes, from the tiny to the gigantic, waving delicate fronds, grassy strands, spikes, mosses, tubes, tangles, berry-like air bladders and ferns.

The name is an unfair misnomer. On land, we use the term ‘weed’ to refer to unwanted invaders growing in competition with and often to the detriment of cultivated plants. Not so with seaweed, which is an essential part of the underwater environment, providing food and a habitat for marine creatures. Many varieties come packed with a wealth of nutrients, minerals and health benefits, which have been used in medical, culinary, agricultural and beauty concoctions for centuries.

Though used extensively by the ancient Egyptians, Greeks and Romans for the treatment of different ailments, seaweed is most closely associated with the culinary cultures of Japan and China, where it has long formed a central part of the cuisine. Notably, Japan’s Okinawa people, who eat it daily, are the longest living population in the world.