Sequential inorganic chemical analysis of a core from Slapton Ley,Devon, UK

Numerous species of seaweed have been successfully cultivated in the sea for commercial purposes. Although considerable experimental work has been done on on-shore cultivation systems, none of these has yet proved to be economically viable on a sustained basis; nevertheless, such cultivation systems offer the potential for productivities greater than can be achieved in other systems. In on-shore systems, factors other than light can be controlled and provided at saturation levels. As density of biomass is controllable, all the light entering the cultivation system is absorbed. This results in efficient conversion of light energy to biomass when only light is limiting; moreover, density, rather than growth rate, is the major factor determining productivity. As growth of seaweeds in on-shore systems is only vegetative, there is no interruption for reproduction or maturation of the plants, and all of the net production can be recovered. Seaweeds have, though, relatively low percentage carbon composition, compared with terrestrial plants, and this may result in apparent high productivities based on dry matter.