This chapter examines the interplay of physical and ecological energetics between the coastal zone and the shelf proper and along- and across-shelf, including processes occurring at the shelf-open ocean boundary. The flow of energy and nutrients through food webs differs greatly among continental shelves, driven largely by differences in carbon fixation. Tidal fronts occur on numerous shelf regions, but the beststudied fronts are those occurring on the northwest European continental shelf, where tidal energy is strong, particularly in the southern North Sea and in the waters around the British Isles. The persistence of shelf-sea fronts in summer results in the enhancement of primary productivity with, inevitably, an increase in the numbers of potential pelagic consumers. Nutrient concentrations in the water column are generally higher in the northern than in the southern North Sea, reflecting input from the North Atlantic, but there have been significant changes over the past few decades.