The FRAM (FRontiers in Arctic Marine Monitoring) Ocean Observing System uses a multi-platform approach for year-round multidisciplinary ocean observations in harsh and often ice-covered Arctic ecosystems in Fram Strait and the central Arctic. The implementation by the Alfred Wegener Institute started in 2014 and is currently being finalized. FRAM builds on ~20 years of time-series observations in the area, including the LTER Observatory HAUSGARTEN and an oceanographic mooring array crossing Fram Strait at ~79°N. Observations of physics, biogeochemistry, and ecology extend from the sea ice to the seafloor. Measurements and sampling is carried out with moorings, benthic installations, ice-tethered, and mobile platforms (e.g., under-ice ROVs, AUVs, benthic crawlers, moored winches) in combination with regular research vessel campaigns. Most GOOS-EOVs are recorded to address Global Change and the Arctic amplification in terms of warming, decreasing sea ice extent, and acidification, and the effects on biological and biogeochemical processes, biodiversity, and ecosystem functions. The observational approach is introduced and multidisciplinary observations are shown to demonstrate its strength: Water-column recordings by physical and biogeochemical sensors in the marginal ice zone are combined with observations on particle fluxes and plankton communities from particle traps and automated samplers. Connected to benthic time-lapse imaging as well as ship-based observations of planktic and benthic communities, and benthic biogeochemistry show how surface water productivity patterns are reflected in all ecosystem compartments down to the seafloor. These data sets in combination with existing physical and ecological observations, allow analyses of inter-annual variability and long term changes of Arctic ecosystems as well as predictions of future ecosystem functions and health.