H2020 project "AtlantOS", 29 Nov - 1 Dec 2016 workshop The workshop, held at the IO PAN in Sopot brought together 15 experts (and two remote participants) in biogeochemical observations and modelling from several countries around the Atlantic: Brazil,United States, Norway, Ireland, United Kingdom, Belgium, France, Germany and Poland. Comparing the targets developed during this workshop with the current observing capabilities will enable a comprehensive gap analysis (as part of AtlantOS Task 1.2) aimed at providing recommendations for designing optimized and enhanced Atlantic Ocean observing system.