Kelp at Dundrum Bay, Northern Ireland. © Matt Lemon Photography. All Rights Reserved.
Kelps are large seaweeds (algae) belonging to the brown algae (Phaeophyceae) in the order Laminariales. There are about 30 different genera. Kelp grows in underwater forests in shallow oceans, and is thought to have appeared in the Miocene, 23 to 5 million years ago. The organisms require nutrient-rich water with cool temperatures between 6 and 14 °C (43 and 57 °F).
Alga of the year: Multiple uses of the kelp product alginic acid
In 2007, the phycology section of the German Botanical Society who conduct research on algae nominated the kelp Laminaria as ‘Alga of the year’. Together with other large macroalgae, Laminaria species form unique ecosystems which seem to be like the “rainforests of the sea”. These forests represent important habitats and nursery grounds for a large range of marine animals such as crustaceans and fish. Sea urchins, gastropods (slugs and snails) and marine isopods depend on kelps as their food source. Small, broken-off pieces of algal biomass are decomposed by microbes and serve as food for planktonic animals that filter tiny particles out of the water. Off Helgoland kelp forests grow in depths up to 10 m, and in the Mediterranean as deep as 120 m. On the Norwegian coast they extend over many thousands square kilometres.
Because of its unique properties, the natural ingredient alginic acid is used as a stabiliser in the food, cosmetic and pharmaceutical industries: instant-desserts, tomato ketchup and yoghurts, as well as ice-creams and cream cakes maintain their stability with the help of alginic acid. Alginic acid more and more replaces bovine-derived gelatine which has been suspected to transmit BSE. Since alginic acids can not be metabolised by humans, they are contained in many dietary and slimming products. Alginic acid also has applications in biotechnology, for example the separation of substances. Alginic acid is used as a stabilising agent and emulsifier in crèmes, lotions, toothpaste, massage gels and shampoos in the cosmetics and pharmaceutical industries. Calcium alginate is used as a wound-healing agent because it helps to stop bleeding. Also, imprints of dentures are made from alginic acid.
Kelp as a source of renewable energy
Kelp has a high growth rate – some genera can grow as fast as half a metre a day – and its decay is quite efficient in yielding methane, as well as sugars that can be converted to ethanol. It has been proposed that large open-ocean kelp farms could serve as a source of renewable energy.
Many millions of pounds are being invested in seaweed research from Vietnam to Israel to Chile because producing biofuels in the sea removes at a stroke many of the serious problems with conventional biofuels. Though important as greener alternatives to oil, many biofuels are produced from food crops, such as corn and sugar, which drives up global prices in a world where a billion people are already hungry. Biofuel production also consumes increasingly scarce freshwater and the worst examples – those from palm oil – can produce more carbon dioxide than diesel. “Seaweed does not have any of those problems,” says Phil Kerrison, marine scientist at the Scottish Association for Marine Science (Sams). Seaweed farming has even been shown to clean up the pollution from fish farms and kelp grows far more quickly than land plants, turning sunlight into chemical energy five times more efficiently.
According to Professor Mike Cowling, chief scientist at the Crown Estate, “it seems that seaweed could play an important role in providing a secure and reliable supply of green energy, particularly for coastal and island communities.” His colleague Professor Laurence Mee, director of Sams, believes large-scale seaweed farming will become a reality because global competition for resources is intensifying on an increasingly crowded planet. “We have the highest commodity prices in history and we are running out of places to grow things.”