Final conference, Rome October 11, 2016 Temporal variability of particle fluxes and bottom density-driven currents on the Storfjorden continental slope (Svalbard) Leonardo Langone1, Stefano Aliani1, Alessandra D'Angelo1, Federico Giglio1, Stefano Miserocchi1, Manuel Bensi2, Vedrana Kovacevic2, Michele Rebesco2, Laura Ursella2, Davide Deponte2, Anna Wåhlin3 1CNR-ISMAR, Italy, leonardo.langone@ismar.cnr.it 2OGS, Italy 3University of Gothenburg, Sweden Introduction The offshore SW Svalbard Archipelago (Fig. 1) is a region where Atlantic waters, considerably warmer than the locally-formed dense waters, flow northwards embedded in the so-called West Spitsbergen Current (WSC) through the eastern side of the Fram Strait. They keep this region nearly ice-free even during winter season. Additionally, dense waters formed during winter through freezing and brine rejection fill the bottom of the Storfjorden polynya. After their generation, they flow down to the continental slope, and then, geostrophically adjusted move northwards along the isobaths. The cascading of the brine-enriched shelf water can reshape the sea bottom and transport large quantities of water, sediment and associated organic matter, and gases (mainly CO2 and dissolved O2) toward the deep-sea environment. In particular, two contourite depositional systems were discovered in the area: the Isfjorden and Bellsund contourite drifts (Rebesco et al., 2013). Sanchez-Vidal et al. (2015) have investigated from July 2010 to July 2011 the environmental processes driving the sinking of particles and organic matter along the Storfjorden slope, by using 4 moorings equipped with automatic sediment traps, current meters and temperature and salinity recorders. Higher lithogenic ﬂuxes and coarsening of settling particles in late winter–early spring have been forced by a seasonal WSC intensification. An increased arrival of ice rafted detritus by sea ice transport from the southern Spitsbergen coast along with terrestrial organic matter was also observed during winter. In spring–summer, phytoplankton blooms have augmented the biogenic compounds (opal, organic carbon and calcium carbonate) of the downward particle fluxes (Sanchez-Vidal et al., 2015). Several studies suggest that reduced sea ice extent and thickness caused by global warming are likely to increase the export of marine organic matter as a result of a longer phytoplankton growing season and enhanced under-ice productivity (Arrigo et al., 2008). To acquire a better understanding of these processes and assess the impact of climate change on the cycling of organic carbon (OC), including shifting the relative magnitude of the main OC sources, further long-term observations in polar continental margins are considered necessary. In the framework of different projects (Eurofleets2-PREPARED and BURSTER, Premiale-ARCA and PNRA-DEFROST) and in a common effort between CNR-ISMAR, OGS and University of Gothenburg, the mooring S1 has been re-deployed in June 2014 and serviced annually by using the RVs G.O. Sars, Helmer Hansen and Polarstern. Although the experiment is still in progress, first results are presented in the following section. Results The mooring S1 is specifically devoted to investigate near-bottom processes. For this reason, instruments are placed close to the seabed (Fig.1). From the bottom, an Aanderaa RCM8 current- meter at ~20 m is tethered to the mooring line, just 5 m below the automatic McLane sediment trap. At the same depth, a SBE16plus recorder of temperature, conductivity and turbidity is mounted. At the mooring top, a downward looking RDI 150 kHz ADCP is placed.