Plankton community respiration and bacterial metabolism in a North Atlantic Shelf Sea during spring bloom development (April 2015)

•We present temporal evolution of plankton metabolism at short temporal scales (≤5 days).•Concurrent increase in primary production and plankton community respiration during a bloom event.•Free-living bacteria are not the major producers of CO2.•Locally synthesized organic carbon sufficient to fulfil bacterial carbon demand in euphotic waters.•Bacterial growth efficiency varied during the evolution of the spring bloom.