A dictionary definition of the word ‘weed’ reads ‘a valueless plant growing wild’. When using the word ‘seaweed’ to define our marine algae, nothing could be further from the truth. We have a vast range of plants thriving all around our coasts which have enormous potential.

There are records of seaweed harvesting in Ireland dating back to the Pre-Norman 12th Century. It provided, in the form of dilsk or dulse and carrageen moss a nutrient-rich food source, and a fertiliser in the form of kelp and bladder wrack.

From the 18th century, ash was extracted from kelp in special kilns dotted along the western seaboard. The ash was spread on the soil as a fertiliser and also used in the making of both soap and glass. It provided a valuable source of iodine.

In solution, iodine is a powerful anti-infective and is often used to treat open wounds. It is also nutritionally vital for the proper functioning of the thyroid gland.

Since the 1940s, seaweed has been harvested, dried and milled for use as an animal feed additive and a liquid plant food. The algae ascophyllum nodosum also known as knotted wrack, is harvested all along the west coast as the main ingredient in a high-performance fertiliser.

This liquid feed is exported all over the world and is used in agriculture and horticulture, as well as on sports grounds and golf courses. This seaweed is rich in alginates, which are derivatives of alginic acid, a long-chained hetropolysaccharide. Over 100,000 tonnes of this seaweed are harvested per year.

The red algae or rhodophyte agrose provide the agar which is so sought-after as a growth medium for micro-organisms and for biotechnological applications. Mankind has yet to invent a better growth medium. Agar from Irish waters is exported to bioresearch laboratories worldwide.

Currently, fresh seaweed is harvested in Ireland for use in horticulture, agriculture, cosmetics and food additives, as well as for biotechnology and as biofuel.

Algae fuel, biofuels made from seaweed, are causing government agencies and innovative energy companies to examine the commercial viability of algaculture: the farming of algae as a massive source of energy.

Microalgae have a much faster growth rate than crops grown on land. Using seaweed as an energy source means land needed for food production is not transferred to biomass use for energy crops.

Also, the per-unit yield of lipids (oil) from seaweed is believed to be seven to 30 times as great as the next best crop. Seaweeds can produce up to 60% of their biomass in the form of oil.

Thankfully, the research and development of algae fuel is proceeding at a frenzied pace, with the big players diving in. On January 8th last, a Continental Airlines twin-engine commercial jet consuming an equal mix of algae fuel and normal aircraft fuel in an unmodified engine took to the air.

The flight was the first by US carrier to use an alternative fuel source. The International Air Transport Association’s goal is for its members to have a 10% input of alternative fuel by 2017.

On the 19th June, a joint research and development project for Ireland, Northern Ireland and Scotland was announced by Northern Ireland Energy Minister Arlene Foster. This research into converting marine algae into a new green energy solution may well prove vital in the future, when fossil fuels have all been exhausted.

It is time to look at the plants which live in our tides with the respect they deserve and maybe lose the ‘weed’ word.