Oceanography The Official Magazine of
The Oceanography Society
Volume 25 Issue 03

View Issue TOC
Volume 25, No. 3
Pages 26 - 37

OpenAccess

The Changing Carbon Cycle in the Southern Ocean

By Taro Takahashi , Colm Sweeney , Burke Hales, David W. Chipman, Timothy Newberger, John G. Goddard, Richard A. Iannuzzi , and Stewart C. Sutherland 
Jump to
Article Abstract Citation References Copyright & Usage
Article Abstract

Various human activities, including fossil fuel combustion and forest clearing, emit about eight petagrams (or billion tons) of carbon in the form of CO2 into the atmosphere annually. The global ocean absorbs about two petagrams of CO2, and about a half of that amount is absorbed by the Southern Ocean south of 30°S, thus slowing the rapid accumulation of CO2 in the atmosphere. Partial pressure of CO2 (pCO2) is a measure of the chemical driving force for the CO2 exchange between the ocean and the atmosphere. This paper discusses its space and time distribution over the Southern Ocean. The major sink zone for atmospheric CO2 is located in a latitude belt between 30°S and 50°S, where the biological utilization of CO2 and cooling of warm subtropical waters flowing southward produce low seawater pCO2. Strong winds in this zone also enhance the ocean’s uptake. Although the source-sink conditions vary over a wide range through the seasons in the areas south of 50°S, this zone is a small sink on an annual average. Winter observations show that surface water pCO2 values in the source region for Antarctic Intermediate Water have increased at a rate faster than the atmospheric increase rate, suggesting that the ocean CO2 sink intensity has been weakening for several decades and has changed from a net sink to a net source since 2005. The results of ocean general circulation-biogeochemistry model studies are found to be consistent with the observations.

Citation

Takahashi, T., C. Sweeney, B. Hales, D.W. Chipman, T. Newberger, J.G. Goddard, R.A. Iannuzzi, and S.C. Sutherland. 2012. The changing carbon cycle in the Southern Ocean. Oceanography 25(3):26–37, https://doi.org/10.5670/oceanog.2012.71.

References
    Arrigo, K.R., and D.N. Thomas. 2004. Large scale importance of sea ice biology in the Southern Ocean. Antarctic Science 16(4):471–486, https://doi.org/10.1017/S0954102004002263.
  1. Arrigo, K.R., and G.L. van Dijken. 2007. Interannual variation in air-sea flux in the Ross Sea, Antarctica: A model analysis. Journal of Geophysical Research 112, https://doi.org/10.1029/2006JC003492.
  2. Bakker, D.C.E., M. Hoppema, M. Schröder, W. Geibert, and H.J.W. de Baar. 2008. A rapid transition from ice covered CO2–rich waters to a biologically mediated CO2 sink in the eastern Weddell Gyre. Biogeosciences Discussions 5:1,205–1,235, https://doi.org/10.5194/bgd-5-1205-2008.
  3. Bakker, D.C.E., H.J.W. de Baar, and U.V. Bathmann. 1997. Changes of carbon dioxide in surface waters during spring in the Southern Ocean. Deep-Sea Research Part II 44:91–127, https://doi.org/10.1016/S0967-0645(96)00075-6.
  4. Bates, N.R., D.A. Hansell, C.A. Carlson, and L.I. Gordon. 1998. Distribution of CO2 species, estimates of net community production and sea-air CO2 exchange in the Ross Sea polynya. Journal of Geophysical Research 103(C2):2,883–2,896, https://doi.org/10.1029/97JC02473.
  5. Bender, M.L., D.T. Ho, M.B. Hendricks, R. Mika, M.O. Battle, P.P. Tans, T.J. Conway, B. Sturtevant, and N. Cassar. 2005. Atmospheric O2/N2 changes, 1993–2002: Implications for the partitioning of fossil fuel CO2 sequestration. Global Biogeochemical Cycles 19, GB4017, https://doi.org/10.1029/2004GB002410.
  6. Böning, C.W., A. Disper, M. Visbeck, S.R. Rintoul, and F.U. Schwartzkopf. 2008. The response of the Antarctic Circumpolar Current to recent climate change. Nature Geoscience 1:864–869, https://doi.org/10.1038/ngeo362.
  7. Boutin, J., L. Merlivat, C. Henocq, N. Martin, and J.B. Sallee. 2008. Air-sea CO2 flux variability in frontal regions of the Southern Ocean from CARbon Interface OCean Atmosphere drifters. Limnology and Oceanography 53(5, part 2):2,062–2,079, https://doi.org/10.4319/lo.2008.53.5_part_2.2062.
  8. Chipman, D.W., J. Marra, and T. Takahashi. 1993. Primary production at 47°N and 20°W in the North Atlantic Ocean: A comparison between the 14C incubation method and the mixed layer carbon budget. Deep-Sea Research Part II 40(1/2):151–169, https://doi.org/10.1016/0967-0645(93)90011-B.
  9. Dong, S., J. Sprintall, S.T. Gille, and L. Talley. 2008. Southern Ocean mixed-layer depth from Argo float profiles. Journal of Geophysical Research 113, C06013, https://doi.org/10.1029/2006JC004051.
  10. Downs, S.M., A. Gnanadesikan, S. Griffies, and J.L. Sarmiento. 2011. Water mass exchange in the Southern Ocean in coupled climate models. Journal of Physical Oceanography 41:1,756–1,771, http://journals.ametsoc.org/doi/abs/10.1175/2011jpo4586.1.
  11. GLOBALVIEW-CO2 (Cooperative Atmospheric Data Integration Project - Carbon Dioxide). 2006. CD-ROM, NOAA CMDL, Boulder, Colorado. (Also available on Internet via anonymous FTP to ftp.cmdl.noaa.gov, Path: ccg/co2/GLOBALVIEW.)
  12. Gruber, N., M. Gloor, S.E. Mikaloff Fletcher, S.C. Doney, S. Dutkeiwicz, M.J. Follows, M. Gerber, A.R. Jacobson, F. Joos, K. Lindsay, and others. 2009. Oceanic sources, sinks, and transport of atmospheric CO2. Global Biogeochemical Cycles 23, GB1005, https://doi.org/10.1029/2008GB003349.
  13. Gurney, K.R., D. Baker, P. Rayner, A.S. Denning, and TransCom 3 L2 modelers. 2008. Interannual variations in regional net carbon exchange and sensitivity to observing networks estimated from atmospheric CO2 inversions for the period 1979 to 2006. Global Biogeochemical Cycles, 22, GB3025, https://doi.org/10.1029/2007GB003082.
  14. Hales, B., D.W. Chipman, and T. Takahashi. 2004. High-frequency measurement of partial pressure and total concentration of carbon dioxide in seawater using microporous hydrophobic membrane contactors. Limnology and Oceanography Methods 2:356–364, https://doi.org/10.4319/lom.2004.2.91.
  15. Hales, B., and T. Takahashi. 2004. High-resolution biogeochemical investigation of the Ross Sea, Antarctica, during the AESOPS (U.S. JGOFS) Program. Global Biogeochemical Cycles 18, GB3006, https://doi.org/10.1029/2003GB002165.
  16. Jacobson, A.R., S.E. Mikaloff Fletcher, N. Gruber, J.L. Sarmiento, and M. Gloor. 2007. A joint atmosphere-ocean inversion for surface fluxes of carbon dioxide. Part 2: Regional results. Global Biogeochemical Cycles 21, GB1020, https://doi.org/10.1029/2006GB002703.
  17. Kanamitsu, M., W. Ebisuzaki, J. Woollen, S.-K. Yang, J.J. Hnilo, M. Fiorino, and G.L. Potter. 2002. NCEP-DOE AMIP-II Reanalysis (R-2). Bulletin of the American Meteorological Society 83:1,631–1,643. (The updated data to 2005 were downloaded on March 22, 2005, from ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis2/gaussian.grid.)
  18. Le Quéré, C., C. Rodembeck. E. Buitenhuis, T. Conway, R. Langenfelds, A. Gomez, C. Labuschagne, M. Ramonet, T. Nakazawa, N. Metzl, and others. 2007. Saturation of the Southern Ocean CO2 sink due to recent climate change. Science 316:1,735–1,738, https://doi.org/10.1126/science.1136188.
  19. Le Quéré, C., T. Takahashi, E.T. Buitenhuis, C. Rodenbeck, and S.C. Sutherland. 2010. Impact of climate change and variability on the global oceanic sink of CO2. Global Biogeochemical Cycles 24, GB4007, https://doi.org/10.1029/2009GB003599.
  20. Lenton, A., and R.J. Matear. 2007. Role of the Southern Annular Mode (SAM) in Southern Ocean CO2 uptake. Global Biogeochemical Cycles 21, GB2016, https://doi.org/10.1029/2006GB002714.
  21. Lizotte, M.P. 2001. The contributions of sea ice algae to Antarctic marine primary production. American Zoologist 41:57–71, https://doi.org/10.1093/icb/41.1.57.
  22. Lovenduski, N.S., N. Gruber, S.C. Doney, and I.D. Lima. 2007. Enhanced CO2 outgassing in the Southern Ocean from a positive phase of the Southern Annual Mode. Global Biogeochemical Cycles 21, GB2026, https://doi.org/10.1029/2006GB002900.
  23. Manning, A.C., and R.F. Keeling. 2006. Global oceanic and land biotic carbon sinks from the Scripps atmospheric oxygen flask sampling network. Tellus 58B:95–116, https://doi.org/10.1111/j.1600-0889.2006.00175.x.
  24. Metzl, N., C. Brunet, A. Jabaud-Jan, A. Poisson, and B. Schauer. 2006. Summer and winter air-sea CO2 fluxes in the Southern Ocean. Deep Sea Research Part I 53:1,548–1,563, https://doi.org/10.1016/j.dsr.2006.07.006.
  25. Metzl, N. 2009. Decadal increase of oceanic carbon dioxide in Southern Indian Ocean surface waters (1991–2007). Deep Sea Research Part II 56:607–619, https://doi.org/10.1016/j.dsr2.2008.12.007.
  26. Mikaloff Fletcher, S.E., N. Gruber, A.R. Jacobson, S.C. Doney, S. Dutkiewicz, M. Gerber, M. Follows, F. Joos, K. Lindsay, D. Menemenlis, and others. 2006. Inverse estimates of anthropogenic CO2 uptake, transport, and storage by the ocean. Global Biogeochemical Cycles 20, GB2002, https://doi.org/10.1029/2005GB002530.
  27. Moore, J.K., and M.R. Abbott. 2000. Phytoplankton chlorophyll distributions and primary production in the Southern Ocean. Journal of Geophysical Research 105:28,709-28,722, https://doi.org/10.1029/1999JC000043.
  28. NCEP/DOE 2 Reanalysis Data. 2005. Ice field data provided by NOAA/OAR/ESRL PSD, Boulder CO, via web site: http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis2.gaussian.html.
  29. Newberger, T. 2004. Underway pCO2 System Users Manual, Palmer 2004 pCO2 System. Lamont-Doherty Earth Observatory, Palisades, NY, 23 pp., http://www.ldeo.columbia.edu/res/pi/CO2/carbondioxide/text/Palmer_PCO2_man_1_2.pdf.
  30. Orsi, A.H., T. Whitworth III, and W.D. Nowlin. 1995. On the meridional extent and fronts of the Antarctic Circumpolar Current. Deep Sea Research Part I 42:641–673, https://doi.org/10.1016/0967-0637(95)00021-W.
  31. Quay, P., R. Sommerup, T. Westby, J. Sutsman, and A. McNichol. 2003. Changes in the 13C/12C of dissolved inorganic carbon in the ocean as a tracer of anthropogenic CO2 uptake. Global Biogeochemical Cycles 17(1), 1004, https://doi.org/10.1029/2001GB001817.
  32. Rubin, S.I. 2003. Carbon and nutrient cycling in the upper water column across the Polar Frontal Zone and Antarctic Circumpolar Current along 170°W. Global Biogeochemical Cycles 17, 1087, https://doi.org/10.1029/2002GB001900.
  33. Rubin, S.I., T. Takahashi, D.W. Chipman, and J.G. Goddard. 1998. Primary production and nutrient utilization ratios in the Pacific Sector of the Southern Ocean based on seasonal changes in seawater chemistry. Deep Sea Research 45:1,211–1,234, https://doi.org/10.1016/S0967-0637(98)00021-1.
  34. Sabine, C.L., R.A. Feely, N. Gruber, R.M. Key, K. Lee, J.L. Bullister, R. Wanninkhof, C.S. Wong, D.W.R. Wallace, B. Tilbrook, and others. 2004. The oceanic sink for anthropogenic CO2. Science 305:367–371, https://doi.org/10.1126/science.1097403.
  35. Sarmiento, J.L., and N. Gruber. 2006. Ocean Biogeochemical Dynamics. Princeton University Press, Princeton, NJ, 503 pp.
  36. Signorini, S.R., and C.R. McClain. 2009. Effect of uncertainties in climatologic wind, ocean pCO2, and gas transfer algorithms on the estimate of global sea-air CO2 flux. Global Biogeochemical Cycles 23, GB2025, https://doi.org/10.1029/2008GB003246.
  37. Sweeney, C. 2003. The annual cycle of surface CO2 and O2 in the Ross Sea: A model for gas exchange on the continental shelves of Antarctica. Pp. 295–312 in Biogeochemistry of the Ross Sea. G.R. DiTullio and R.B. Dunbar, eds, Antarctic Research Series, vol. 78, American Geophysical Union, Washington, DC, https://doi.org/10.1029/AR078.
  38. Sweeney, C., E. Gloor, A.R. Jacobson, R.M. Key, G. McKinley, J.L. Sarmiento, and R. Wanninkhof. 2007. Constraining global air-sea gas exchange for CO2 with recent bomb 14C measurements. Global Biogeochemical Cycles 21, GB2015, https://doi.org/10.1029/2006GB002784.
  39. Takahashi, T., and D.W. Chipman. 2012. CO2 transport in deep waters off Wilkes Land. Oceanography 25(3):24–25, https://doi.org/10.5670/oceanog.2012.70.
  40. Takahashi, T., S.C. Sutherland, R. Wanninkhof, C. Sweeney, R.A. Feely, D.W. Chipman, B. Hales, G. Friederich, F. Chavez, C. Sabine, and others. 2009. Climatological mean and decadal changes in surface ocean pCO2, and net sea-air CO2 flux over the global oceans. Deep Sea Research Part II 56: 554–577, https://doi.org/10.1016/j.dsr2.2008.12.009.
  41. Takahashi, T., S.C. Sutherland, and A. Kozyr. 2011. Global Ocean Surface Water Partial Pressure of CO2 Database: Measurements Performed During 1957–2010 (Version 2010). ORNL/CDIAC-159, NDP-088(V2010). Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, https://doi.org/10.3334/CDIAC/otg.ndp088(V2010).
  42. Wanninkhof, R. 1992. Relationship between wind speed and gas exchange. Journal of Geophysical Research 97:7,373–7,382, https://doi.org/10.1029/92JC00188.
  43. Weiss, R.F. 1974. Carbon dioxide in water and seawater: The solubility of a non-ideal gas. Marine Chemistry 2:203–215, https://doi.org/10.1016/0304-4203(74)90015-2.
  44. Worby, A.P., C.A. Geiger, M.J. Paget, M.L. Van Woert, S.F. Ackley, and T.L. DeLiberty. 2008. Thickness distribution of Antarctic sea ice. Journal of Geophysical Research 113, C05S92, https://doi.org/10.1029/2007JC004254.
Copyright & Usage

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.