Due to its position as the principal connector of the major ocean basins, the Southern Ocean strongly impacts climate, sea level, biogeochemical cycles and biological productivity on a global scale. Any change in the region thus has global ramifications. Recent scientific advances suggest that change is indeed already underway. The Southern Ocean is warming and freshening throughout most of the ocean depth1,2, and major currents are postulated to be shifting south in some regions, causing regional changes in sea level3,4 and shifts in the distribution of organisms5. These changes, and enhanced upwelling due to strengthening winds, have resulted in the supply of additional heat to the rim of Antarctica in some sectors, increasing melt rates of glacial ice6,7 and impacting strongly on marine ecosystems8. Further, the future of the Southern Ocean carbon sink is a topic of vigorous debate1,9,10, with the Southern Ocean taking up a large percentage of anthropogenic carbon, resulting in an increase in acidity of 30%11. Complex feedbacks in the Southern Ocean will impact on the future trajectory of the climate system and ecosystem, but these are currently poorly understood, hindering our predictive skill.
The SOOS will focus its efforts on collecting data that will address six Science Themes, which were identified as being the most compelling scientific and societal challenges that relate to the Southern Ocean.
A number of steps are required to reach the ultimate goal of a sustained, multidisciplinary, and internationally coordinated observing system. First and foremost is the identification of the Essential Ocean Variables and Ecosystem Essential Variables that are required to address the key issues outlined in the SOOS Scientific Themes. Following this, a quantification of the required observations, and development of a sampling strategy for each variable is required. The SOOS will be working with many international programmes and projects to develop these strategies.