The deep prolific kelp beds whose tops lie like thick glossy bands across the tidal zone at lowest water, are the home, protectors and nourishers to a range of sea fauna and flora; from fish, sea squirts, sponges, starfish, soft corals and invertebrates to red seaweed epiphytes that grow along their stipes. At the edge of the low tide line are the wavy sugar kelps (Saccharina latissima) and Furbellows (Saccorhiza polyschides), followed in deeper succession by wispy Dabberlocks (Alaria esculenta) and long olive blades of Oarweed (Laminaria digitata) in the sublittoral zone, culminating in bigger kelps forests of Cuvie (Laminaria hyberborea), whose leathery leaves prefer life well beneath the waves.
Kelp has been harvested for centuries along the coast of Scotland for a variety of purposes. Cast kelp was collected and used on fields as fertiliser, but also distributed as food stuff for livestock. In the late 18th and early 19th centuries, coastal communities established a thriving industry creating alkalines in the form of ash (potash and soda) for soap and glass manufacture by burning and lixiating kelp along the beaches – a major industry in the Western Hebrides and Orkney up until the 1830’s. In the 1840’s kelp was also found to have a very high iodine content (containing ten times as much as Fucus species), and became the universal source of this essential element responsible for the synthesis of thyroid gland hormones.
Eating kelp provides a much richer source of protein, potassium, magnesium and other trace elements and minerals than most vegetables. It is also rich in the omega-3 fatty acid EPA and can aid nutrition and absorbtion by acting as a natural cleanser for the intestines. Various health experts recommend kelp to prevent heart disease and to lower cholesterol, it works to reduce inflammation, and as with wracks, the alginates also help to reduce the amount of fat the body digests thus acting as an aid against obesity.
Several studies have also found that kelp extracts appeared to show some activity against HIV in cell culture and that both Saccharinas and Laminarias contain fucodin, a complex polysaccharide that can acts as an anti-tumour and anti-cancer agent inhibiting and promoting the destruction of cancer cells.
Alginic acid is an important constituent of the cell walls of brown seaweeds and it is mainly responsible for their tensile strength and elasticity, essential for survival in turbulent seawater. Discovered in Japan in the late 1650s or 1660s, Scottish chemist E.C.C. Standford first derived alginates from British kelp in the 1880s.
Alginates quickly became a key ingredient in preparation of modern food stuffs allowing longer shelf life and wider distribution. Tips of living kelps and a variety of Rhodophyta were gathered and processed to make the agar used to stabilise dry cake and biscuit mixes, thicken soups, make ice cream gel and toothpaste smooth. In East Lothian, between 1949 and 1956, a nascent kelp industry was trialed by the Institute of Seaweed Research in Musselburgh, using boats fitted with grapples to ‘fish’ for the seaweed. However, the project was abandoned when local farmers protested at the harvesting of one of their age-old sources of crop fertilisers.