The unusual timing of highly productive summer plankton blooms off Greenland indicates a connection between increasing amounts of meltwater and nutrients in these coastal waters. In a new study published today in the international journal Nature Communications, an international group of researchers led by the GEOMAR Helmholtz Centre for Ocean Research Kiel shows that this connection exists, but is much more complex than widely supposed. Whether increasing meltwater has a positive or negative effect on summertime phytoplankton depends on the depth at which a glacier sits in the ocean.