|Enlarge ImageLocation of sites used for a collaborative study with Maureen Raymo (Boston University) and Jerry McManus (WHOI).
The Atlantic Ocean is characterized by a whole ocean overturning cell. Warm, salty tropical upper ocean waters flow northward in the western Atlantic. The heat loss to the overlying cold atmosphere results in a loss of bouyancy, and convection to great depths in the Labrador and Nordic Seas. These newly formed North Atlantic Deep Waters flow southward, eventually exiting the Atlantic basin. Waters that are exported must be replaced. The more vigorous the North Atlantic overturning and southward export, the more warm upper ocean waters that must flow northward to replace them.
Considerable evidence suggests that this strength of the Atlantic Ocean overturning has varied in the past, and that these variations were linked to large climatic changes in the North Atlantic region.
Much of our current work is directed towards reconstructing these past changes for key intervals in the past, and understanding the causes and climatic impacts of these changes. Understanding this link also motivates us to develop surface climate records.
David Thornalley, Lloyd Keigwin, and I have exciting results from multicores we collected south of Iceland in 2014. Stay tuned for publications.
Bill Curry and I completed a cruise Jan 24-Jan 14, 2010 to the western tropical Atlantic (~8°N) to collect long cores to study past ocean circulation. Check out our website blog.
Recent Related Publications (italics indicates student or post-doc lead author):
Oppo, D. W., W. B. Curry, and J. F. McManus, What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1?, Paleoceanography, 30, doi:10.1002/2014PA002667, 2015.Huang, K. F., D. W. Oppo, W. B. Curry, Decreased influence of Antarctic intermediate water in the tropical Atlantic during North Atlantic cold events. Earth Planet. Sci. Lett., 389, 200-208, 2014.
Thornalley, D. J. R., Blaschek, M., Davies, F. J., Praetorius, S., Oppo, D. W., McManus, J. F., Hall, I. R., Kleiven, H., Renssen, H., and McCave, I. N.: Long-term variations in Iceland–Scotland overflow strength during the Holocene, Clim. Past Discuss., 9, 1627-1656, doi:10.5194/cpd-9-1627-2013, 2013.
Oppo, D. W. & Curry, W. B. Deep Atlantic Circulation During the Last Glacial Maximum and Deglaciation. Nature Education Knowledge 3(4):1, 2012. http://www.nature.com/scitable/knowledge/library/deep-atlantic-circulation-during-the-last-glacial-25858002
Makou, M. C., D. W. Oppo, W. B. Curry, South Atlantic intermediate water mass geometry for the last glacial maximum from foraminiferal Cd/Ca, Paleoceanography, 25, PA4101, doi:10.1029/2010PA001962, 2010.
Other Related Publications
Carlson, A., D. W. Oppo, R. E. Came, A. E. LeGrande, L. D. Keigwin, and W. B. Curry, Subtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation, Geology, v. 36; no. 12; p. 991–994; doi: 10.1130/G25080A, 2008.
Came, R. E., D. W. Oppo, W. B. Curry, and J. Lynch-Stieglitz, Deglacial variability in the surface return flow of the Atlantic meridional overturning circulation, Paleoceanography, doi:10.1029/2007PA001450, 2008.
Praetorius, S. K., J. F. McManus, D. W. Oppo and W. B. Curry, Episodic reductions in bottom-water currents since the last ice age. Nature Geosciences, 449 – 452, 2008.
Came, R. E., Curry, W. B., Oppo, D. W., Broccoli, A. J., & Stouffer, R. J. North Atlantic intermediate depth variability during the Younger Dryas: Evidence from benthic foraminiferal Mg/Ca and the GFDL R30 coupled climate model, in Geophysical Monograph Series, Volume 173: Ocean Circulation: Mechanisms and Impacts (Schmittner, A., Chiang, J., Hemmings, S. Editors) pp. 247-264, 2007.
Curry, W. B. and Oppo, D. W., Glacial water mass geometry and the distribution of d13C of CO2 in the Western Atlantic Ocean, Paleoceanography, 20, PA1017, doi:10.1029/2004PA001021, 2005. pdf
Raymo, M.E., D.W. Oppo, B.P. Flower, D.A. Hodell, J. F. McManus, K.A. Venz, K.F. Kleiven, K. McIntyre, Stability of North Atlantic water masses in face of pronounced natural climate variability, Paleoceanography, 19, doi:10.1029/2003PA000921, 2004. pdf
Came, R. E., D. W. Oppo, W. B. Curry, Atlantic Ocean circulation during the Younger Dryas: insights from a new Cd/Ca record from the western subtropical South Atlantic, Paleoceanography, 18, doi:10.1029/2003PA000888, 2003.
Oppo, D. W., J. F. McManus, and J. L. Cullen, Deepwater variability in the Holocene Epoch, Nature 422, 277-278, 2003.
Marchitto, T. M., Jr., D. W. Oppo, and W. B. Curry, Paired benthic foraminiferal Cd/Ca and Zn/Ca evidence for a greatly increased presence of Southern Ocean Water in the glacial North Atlantic, Paleoceanography, 17, doi:10.1029/2000PA000598, 2002.
Oppo, D. W., L. D. Keigwin, J. F. McManus, and J. L. Cullen, Evidence for millennial scale variability during Marine Isotope Stage 5 and Termination II, Paleoceanography, 16, 280-292, 2001.
Oppo, D. W., and M. Horowitz, Glacial deepwater hydrography: South Atlantic benthic Cd/Ca and d13C evidence, Paleoceanography, 15, 147-160, 2000.
Oppo, D.W. and S. J. Lehman, Suborbital timescale variability of North Atlantic deep water during the past 200,000 years, Paleoceanography, 10, 901-910,1995.
Oppo, D. W., M. E. Raymo, G. P. Lohmann, A. C. Mix, J. D. Wright, and W. B. Prell, A d13C record of Upper North Atlantic Deep Water during the past 2.6 myrs, Paleoceanography, 10, 395-414, 1995. pdf
Oppo, D. W., and Y. Rosenthal, Cd/Ca Changes in a deep Cape Basin core over the past 730,000 years: Response of circumpolar deepwater variability to northern hemisphere ice sheet melting?, Paleoceanography, 9, 661-675, 1994.
Oppo, D.W. and S. J. Lehman, Mid-depth circulation of the subpolar North Atlantic during the Last Glacial Maximum, Science 259, 1148-1152, 1993.
Oppo, D. W., and R. G. Fairbanks, Atlantic ocean thermohaline circulation over the last 150,000 years: Relationship to climate and atmospheric CO2. Paleoceanography, 5, 277-288, 1990.
Oppo, D. W., R. G. Fairbanks, A. L. Gordon, N. J. Shackleton, Late Pleistocene Southern Ocean d13C Variability. Paleoceanography, 5, 43-54, 1990.
Oppo, D. W., and R. G. Fairbanks, Variability in the deep and intermediate water circulation of the Atlantic Ocean: Northern Hemisphere modulation of the southern ocean. Earth and Planet. Sci. Letts., 86, 1-15, 1987.