Bladder wrack

When: All year round

Scientific name: Fucus vesiculosus

Gaelic name: Propach

Length: Fronds vary in length from less than 10cm up to 90cm

Where: Along the rocky shores of the Firth of Forth

There have probably been many times when you've wandered along a rocky shoreline, pottering past the humble seaweeds strewn over the rocks, or floating a little sadly in the pools, not giving them a second thought. Bladderwrack is one of the most common seaweeds found along the coast of the North Sea, and has been of great cultural and ecological value for centuries!

Often growing in large clumps along the intertidal area of the shore, bladderwrack is an easy presence to overlook when strolling along the coast. This species is a type of marine algae, commonly referred to as seaweed. In the water, it provides shelter for many marine invertebrates such as tube worms and snails. Bladderwrack grows in fronds from a central point that is attached to a rock or other solid surface; the fronds can vary in length and colour, from vibrant green to a murky brown. Each frond has a central vein, with the frond often forking at the end to accommodate two large air bubbles. These air bubbles help the algae to float, meaning that is it high in the water and able to absorb sunlight for photosynthesis. The air sacs also contain mechanisms that allow the seaweed to reproduce.

Bladderwrack is rich in a variety of chemicals and nutrients such as potassium, calcium and magnesium. It also contains high levels of iodine, and was in fact the original source of this chemical, used for medical treatment in the early 1800s. Because bladderwrack is so nutrient rich, it has been the subject of many fad diets and health supplements over the years. It was also used as a soil fertiliser, with farmers harvesting great amounts from the coast and dumping it on land to rot, allowing the nutrients to go into the soil and help fertilise the crops. There was even a New Year's Day tradition in some areas of Scotland whereby folk would gather a large heap of the seaweed and dump it on their veg patch, bringing the sea to the land and making way for a fine yield later in the year.

Another favourite pastime in the colder months for youngsters was to sneak a handful of bladderwrack into the fire, waiting for the loud 'POP!' from the bursting air bubbles to startle older relatives who may have been dosing off by the hearth. Who knew seaweed was so versatile, functioning as both a valuable agricultural resource and a sneaky prank! There are a whole other range of uses and fantastic facts about bladderwrack to discover. Visit http://www.wildlifetrusts.org/species/bladder-wrack to learn more!

Photo: Teun Spaans, Wikimedia commons