Italian Marine Arctic Experimental Infrastucture in Ny-Ålesund, Svalbard -IMEI

Observing systems are the tool to study climate change when they provide the basic information to assess changes: time-series of good quality data. Marine observatories historically involved the collection of physical data as seawater temperature and salinity, but, in relative recent time, timeseries have been improved with relevant data about C fluxes and other climate related variables., e.g. nutrients, DMS or dissolved CO2, also thanks to improved technology of measurements. Parallel to data collection by moored instruments, time-series are also derived from regular hydrological survey and CTD casts. Although these CTD surveys do not have the robust time coverage of moorings, they are often replicated on a regular basis, resulting in a time-series. The marine observing system in Ny-Ålesund provides a full coverage of the major ocean variables relevant to monitor climate-related changes in Arctic sea water properties. It has been built around the permanent mooring Dirigibile Italia and has been improved with other measurements and observations. Italian moorings were first deployed at sea in September 2000 and 2001 in a site that was in the innermost part of the fjord at that time (Aliani et al., 2004). Melting of tidewater glaciers' ice tongues produced in big changes in Ny-Ålesund and the mooring Dirigibile Italia, which is the core of the present-day observing system, has been positioned close to the inner moraine. Sediment traps and new sensors were added to the traditional CT recorders and regular CTD surveys were performed within FIKO project during moorings maintenance, resulting in a large data set every year since September 2010 when the mooring was first deployed. These data after Quality Control will be delivered to the CNR Arctic Data Center and available for modelling. Taking advantage of the presence of Dirigibile Italia marine observatory, experiments have been performed in Ny-Ålesund about the microbial communities in seawater and about the technological exploitation of autonomous vehicles for measuring in extreme and very dangerous environments as the glacier's front, which successfully brought an instrumented AUV to touch Kronebreen glacier (Zappalà et al., 2016, 2017). Time-series of thermohaline properties from the mooring Dirigibile Italia (MDI) revealed a large seasonal variability (? = -1.82 / 6.26°C, S = 34 / 35) and from the beginning of the time-series an increasing trend in temperature (0.07 °C y-1) was measured showing constant minima, and progressively higher warm peaks. An average total mass flux (TMF) of about 20 g m-2 d-1, with the highest peaks recorded in summer-fall months (avg. flux, ~100 g m-2 d-1) and reduced fluxes in autumn-winters (avg. flux, ~7 g m-2 day-1). The terrestrial input due to the melting of glacier terminations generated an increase of the detritus, and the surface runoff introduced debris into the sea from the permafrost surface layer erosion (D'Angelo et al., 2018). All this variability may affect prokaryotic and phytoplanktonic biomass and microbial remineralization rates over short time scales (Azzaro et al., 2017; Caroppo et al., 2017). Nowadays, the Italian marine experimental platform has two pillars. The first is the marine observatory centered on the mooring(s) MDI which will deliver oceanographic data to IADC. The second pillar is the experimental platform that derives from the presence of the marine observatory, which is used for dedicated experiments. Together with Climate Change Tower atmospheric measurements, they are a solid and multidisciplinary approach to monitoring climate change in the Arctic.