Moored sediment trap arrays were deployed from September 2011 to August 2012 on both sides of the Gakkel Ridge in the Nansen and Amundsen Basins to measure vertical particle flux at 200 m and 3800 m under near complete ice cover in the Central Arctic Ocean (CAO). Although the moorings where deployed relatively close to each other and vertical flux pattern of particulate organic matter (POC) was similar, particle flux patterns of total particulate matter (TPM), of particulate biogenic silica (PbSi), and of dominant diatom species were different. Whereas in the CAO ice related diatoms mainly dominated the recognizable flux fraction, faecal material usually prevailed in traps deployed at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN in the periodically ice covered eastern Fram Strait between 2000 and 2012, pointing towards different systems of organic matter production and modification. Results of biomarker composition analyses of the sinking particles confirmed those differences related to ice cover. Molecular genetic approaches were introduced to further understand differences in protist sedimentation. Since 2014, investigations are continuing within the greater framework of the Arctic long-term observatory ‘Frontiers of Arctic Marine
Monitoring’ (FRAM) that has been established to improve our knowledge of environmental and biological data in high temporal and spatial resolution in ice covered waters.