Biogeochemical cycling of nutrients and marine primary productivity off the Greenland coast are subject to significant changes due to climate warming and accelerated melting of glaciers. The role of meltwater input on nutrient cycling and phytoplankton production was evaluated through CTD measurements, nutrient and isotope analyses on seawater samples collected from the south-west Greenland margin and the Labrador Sea during the DY081 research expedition which took place in July 2017. We particularly focused on examining the meltwater input of nutrient silicon and its utilization by diatoms, through the analyses of seawater δ30Si (using a MultiCollector-Inductively Coupled Plasma-Mass Spectrometer), amorphous silica particulate concentration, and diatom biogenic silica production (using the radioisotope 32Si tracer).