ESTIMATES OF NEW PRODUCTION IN THE MID-NORTH-ATLANTIC

The principal aim of this paper is to demonstrate how the major features of primary production are influenced by climatological change. The roles played by seasonal change in mixed layer depth and the vertical distribution of a key limiting nutrient are emphasized. The model traces the sequences of primary production as the sun moves from the winter to summer solstice. Seasonal change in primary production is regulated by light at high latitudes during winter months and nutrients during summer months, where at mid and low latitudes nutrients limit production. The annual pattern of production down the central meridian reflects the vertical distribution of nitrate-nitrogen in cross-sections of the mid-ocean. In turn, this pattern of nutrient distribution reflects the density structure due to the currents and gyres of the North Atlantic. The model produces estimates of 'new primary production' which are consistent when compared with measured values. It should be useful for global estimates of primary production. © 1990 Oxford University Press.