Fig. 1

2018 spring phytoplankton bloom at Helgoland Roads and associated datasets. Estimated biovolumes of abundant phytoplankton taxa (stacked colored areas) as assessed by microscopy and of total cell counts (TCC) of DAPI (4′,6-diamidino-2-phenylindole)-stained bacteria (black line). Complete data was sampled until the end of May. Additional data for June is shown to visualize the end of the bloom but does not include TCC and Dinophyceae biovolume information. The core sampling period from March 1 until May 31 is indicated by a gray area on the abscissa. Additional data including abundances of non-photosynthetic plankters are provided in Additional file 2: Fig. S1 and Additional file 3. Associated omics sampling dates are indicated by colored circles at the bottom