ABSTRACT

Coastal shelf seas receive nutrients from a diverse range of sources including oceans, rivers and atmosphere, local water-column and sea-bed recycling of biologically produced organic compounds. Centric diatoms would seem to be the characteristic life-form of the pelagic biome in northwest European seas, in which the metaphorical understorey is of small phytoflagellates, which can fluorish when the main vegetative cover is cleared. The biological uptake of iron is influenced both by iron chemistry in sea water and the cellular uptake mechanisms. The organic matter made, and the chemical elements harnessed by, these phytoplankters, supports a pelagic food web leading by way of herbivorous protozoa and small invertebrates to carnivorous larger invertebrates, fish, and sea mammals and birds. A unique feature of the North Sea project was that a consistent grid of stations was worked in the southern North Sea once a month for fifteen months.