PART I - THE CULTIVATION OF LARGE BROWN ALGAE AS AN ENERGY CROP. PART II - BIOMASS FROM OFFSHORE SEA AREAS OF EUROPE
The main aim of the work was to develop a method of cultivating large brown algae in the open sea. This was successfully achieved using Alaria esculenta and Laminaria saccharina. A third species, Saccorhiza polyschides, was found to be less suitable. Cultivation took place on horizontal ropes suspended 1-10 m below the sea surface. A simple system of buoys and weights proved effective in maintaining the depth of the ropes. The system usually survived winter storms. The method involved culture of the young stages of the plants on string under controlled conditions, usually for 20-40 days. Short lengths of the string were then inserted into the rope in the sea during winter and spring. Groups of plants grew both on the string and on the rope itself at the point of attachment. The plants grew rapidly during spring and early summer. Winter seeded Alaria stopped growing in late May/early June, while spring seeded plants continued to grow until mid July. Laminaria continued to grow until early September when it was harvested. In both species production was higher in winter seeded plants than in spring seeded ones. A depth of 2 m was found to be suitable for growth of winter seeded plants. By seeding at depths of 3, 5 and 10 m (the latter rope raised to 2 m after 6 weeks) diatom growth was inhibited, resulting in increased survival of spring seeded plants, but production was still lower than from winter seeded ones. Production levels of 1.1 kg dry weight/m of rope by 10 groups of Alaria seeded at 5 cm intervals and 2.8 kg dry weight/m of rope by 5 groups of Laminaria seeded at 10 cm intervals were obtained. There were indications that these levels could be substantially increased by seeding the plants at very high densities. The organic content of the weed was 68-74% of dry weight for Alaria and 61-65% for Laminaria. Preliminary experiments suggest that both species could be stored by ensilage.
Bibliographic Reference: EUR 9990 EN (1985), MF, PART I AND PART II, 117 P. BFR 300, BLOW-UP COPY BFR 585, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124033000 / Last updated on: 1987-01-01
Available languages: en