The Food Production in the Sea and the Annual Cycle of Faeroese Marine Birds

Abstract

the winter period is not sufficiently strong for an effective CO2 assimilation of the plankton algae, even in the uppermost water layers. Off the coasts of the Faeroes the phytoplankton production begins in May and does not cease until in August or even September. The considerable length of the period in which phytoplankton production takes place is due to the fact that in these waters a pronounced mixing of the surface water with deepsea water, rich in nitrates and phosphates, takes place during the whole summer. In areas with stabilized water-masses, without any upwelling of bottom-water, the phytoplankton production will cover one month only. After the dead winter-period, in which the planktonic algae are practically absent-being represented only by scattered spores and cells-large quantities of nutritive salts are present in the surface water layers and give rise to a vigorous