Studies on the growth and nitrogen assimilation of the bloom dinoflagellate Gyrodinium aureolum Hulburt

Growth experiments were carried out with laboratory culturesof Gyrodinium aureolum. Physiological studies on CO₂ fixationand nitrogen nutrition were undertaken with a natural populationdominated by the same organism. These studies suggested thatthe population was in a late stage of bloom development andsuffering from a degree of nitrogen limitation. The relevanceof the ammonium enhancement of dark CO₂ fixation as a techniquefor determining the nitrogen status of phytoplankton is discussedas are the difficulties involved in extrapolating results fromlaboratory studies to field situations.