Experimental-ecological investigations onPhaeocystis poucheti (Haptophyceae): cultivation and waste water test
- H. Kayser1
© Biologischen Anstalt Helgoland 1970
1. The planktonic North Sea algaPhaeocystis poucheti was cultivated in the laboratory. The influence of light, temperature and nutrients was investigated by employing several culture methods. The influence of industrial and domestic waste water was also studied.
2. TheP. poucheti forms both colonies and free, motile or nonmotile, single cells. The single cells have the tendency to attach themselves to solid surfaces and, from there, to release continuously new free single cells and small colonies into the ambient water.
3. The multiplication rates of the two planktonic stages and of the sessile stage ofP. poucheti have been determined and their quantitative inter-relations studied under various culture conditions.
4.P. poucheti was cultivated in “Erdschreiberlösung”, “Schreiberlösung” and pure sea water. The cultures were set up (a) in petri dishes, (b) in 1 or 10 l bottles without renewal of nutrients as mass cultures, and (c) in turbidostats, limiting cell density to a constant optimal level by the daily removal of old, and the addition of new, culture medium.
5. Under conditions which ensure a permanent supply of fresh culture medium and a low cell density, the colony stage predominates over the single cell stage. However, if maximum cell density is reached in a nutrient enriched culture medium, the single cell stage is favored, whilst the colony stage very quickly decreases in number. In pure sea water the colony stage predominates all the time.
6. Cultivation in “Schreiberlösung” results in maximum cell densities of about 400,000 cells/ml in the colony stage, and of about 2,000,000 cells/ml in the single cell stage. Cultivation in pure sea water leads to maximum cell densities of about 100,000 cells/ml in the colony stage and of about 18,000 cells/ml in the single cell stage. Under optimum conditions the rate of multiplication in the planktonic stages reaches two cell divisions per day.
7. Industrial waste water (consisting primarily of H2SO4 and FeSO4) from a titanium dioxide factory favors the growth of the colony stage ofP. poucheti in a dilution of 1 part waste water : 100,000 parts “Schreiberlösung”. A dilution of 1 : 4,000 significantly reduces the multiplication rate of colonies. A dilution of 1 : 2,250 is lethal.
8. After addition of unfiltered domestic sewage (from the sewage outflow on Helgoland) in concentrations of 1–5 parts sewage water to 1,000 parts sea water a vigorous development of the colony stage is followed very quickly by damage to the colonies. The single cell stage, however, shows (in these sewage water concentrations) slightly increased multiplication rates all the time. In concentrations up to 10 parts sewage water to 1,000 parts sea water the toxic effect predominates in both stages.