Importance of deep mixing for initiating the North Atlantic spring bloom

The phytoplankton spring bloom is one of the most important recurrent events in the sup-polar part of the Atlantic Ocean. The classical idea is that the bloom is controlled by nutrients and light, but recent observations challenge this hypothesis. During repeated visits to stations in the deep Icelandic and the Norwegian Basins and the shallow Shetland Shelf (26 March to 1 May 2012), we investigated the succession and growth dynamics of microscopic grazers prior to the bloom. We demonstrate that deep mixing of the water column play an important role for predator-prey interactions and that a released grazing pressure could initiate the bloom