SOOS SCIENCE

The Southern Ocean

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 depth^1,2, and major currents are postulated to be shifting south in some regions, causing regional changes in sea level^3,4 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 ice^6,7 and impacting strongly on marine ecosystems⁸. Further, the future of the Southern Ocean carbon sink is a topic of vigorous debate^1,9,10, 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.
 

Implementing the SOOS

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.
 

Cited References

1. Böning, C.W., et al., 2008: The response of the Antarctic Circumpolar Current to recent climate change, Nature Geoscience, 1: 864–869.
2. Gille, S.T., 2008: Decadal-scale temperature trends in the Southern Hemisphere Ocean, Journal of Climate, 16: 4749-4765.
3. Sokolov, S, and Rintoul,S.R., 2009a: Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths, Journal of Geophysical Research, 114(c11): C11018. 
4. Sokolov, S. and Rintoul, S.R., 2009b: Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 2. Variability and relationship to sea surface height, Journal of Geophysical Research, 114(c11): C11019.
5. Cubillos, J.C., et al., 2007: Calcification morphotypes of the coccolithophorid Emiliania huxleyi in the Southern Ocean: Changes in 2001 to 2006 compared to historical data, Marine Ecology Progress Series, 248: 47-54.
6. Jacobs, S.S., 2006: Observations of change in the Southern Ocean, Philosophical Transactions of the Royal Society A, 364: 1657-1681.
7. Jacobs, S.S.,et al., 2011: Stronger ocean circulation and increased melting under Pine Island Glacier ice shelf, Nature Geoscience, 4: 519-524.
8. Schofield, O., et al., 2010: How do polar marine ecosystems respond to rapid climate change? Science, 328: 1520-1523.
9. Le Quéré, C.L., et al., 2007: Saturation of the Southern Ocean CO2 sink due to recent climate change, Science, 316: 1735-1738.
10. Meredith, M.P., et al., 2012: Sensitivity of the overturning circulation in the Southern Ocean to decadal changes in wind forcing, Journal of Climate, doi: 10/1175/2011JCLI4204.1
11. Rintoul, S.R., et al., 2012: The Southern Ocean Observing System: Initial Science and Implementation Strategy, Scientific Committee on Oceanic Research and Scientific Committee on Antarctic Research, ISBN: 978-0-948277-27-6