NATO Arctic Climate Observatory and recent observations on acoustical ambient noise in the Arctic

In 2023, Centre for Maritime Research and Experimentation (CMRE) kick-started a new scientific programme, which aims at studying the effects of climate change on the security sphere. Being the Arctic region one of the most threatened areas but also an important geopolitical hotspot, in June-July 2023 CMRE deployed three deep moorings for monitoring the acoustic-oceanographic conditions in the long term. These moorings constitute the NATO Arctic underwater Climate Observatory (NACO), and they build upon CMRE’s previous effort in 2021-2023 to study underwater acoustic noise and physical oceanographic properties in the Arctic under the Environmental and Operational Effectiveness Programme. In fact, the Arctic is undergoing a process of “Atlantification”, which is affecting not only its oceanographic characteristics, but also its acoustical ones. Wider areas currently covered by compact sea ice are expected to progressively become marginal ice zone. The moorings are equipped with passive acoustic recorders and oceanographic sensors. Although data did not show a clear relation between sea-ice concentration and noise levels in the marginal ice zone, they indicate the presence of transmissions ducts that increase the noise in the high frequencies in the subsurface area. The overall soundscape recorded in Fram Strait will be discussed, including anthropogenic activities. The biological soundscape showed seasonality evidenced by the presence of whale singing. CMRE is currently working at assessing the soundscape components with the aims of monitoring in the long term how they change in consequence of climate change, going from the physical environment (rain, wind, waves) to ecosystem and human activities.