Culture of marine algae using a re-circulating sea water system
© Biologischen Anstalt Helgoland 1970
1. A description is given of a re-circulating sea water system used to supply water for the culture of algae. Sea water is stored in two large storage tanks. From these, water is pumped to a header tank and then flows by gravity to experimental benches in the laboratory. After use, water is returned to the storage tanks. Nontoxic materials are used throughout the system.
2. It is not possible to control the temperature of the laboratory sea water. Although the temperature fluctuation of the laboratory sea water and the surface water of the Menai Straits follow a similar pattern throughout the year, the temperature of the laboratory sea water was always higher than that of the Menai Straits for the year 1967–1968. The difference between the two water masses is least (0.6°–1.8° C) from September–December and greatest (3.0°–4.6° C) from January to March. From April to August the difference varies from 2.4°–3.6° C.
3. Suspended matter is removed from the sea water by allowing sedimentation to occur in the storage tanks and by means of simple filters.
4. The principal disadvantage of using this type of system is the inevitable contamination of cultures by organisms present in the water. The number and species of contaminants depended on the season and the amount of illumination they received.Prasinocladus marinus (Cienk.)Waern.,Pringsheimiella scutata (Reinke)Marchew.,Enteromorpha spp., various diatoms and filamentous and encrusting Phaeophyceae were the main contaminants above 1,075 lux. At intensities below this, species of Cyanophyceae were the main contaminants.
5. The sea water system described has been found satisfactory for the culture of algae for experiments of short duration, and for keeping algae in a healthy condition for long periods.