Research: Reconstructing the Ocean-Climate Link with Geochemical Tracers

The primary thrust of my research is to understand the link between ocean circulation and climate over recent earth history.  I am specifically interested in reconstructing changes in deep water mass source and structure and determining how these are linked with changes in deep ocean nutrient contents and overturning rate.  I primarily use the chemistry of sediment and authigenic precipitates preserved in the marine sedimentary record to reconstruct these past changes. 

Recently, I have been using neodymium (Nd) isotopes to produce high resolution records necessary to reconstruct glacial–interglacial and millennial–scale variability, including a number of studies that examined South Atlantic deep water sourcing changes during deglacial circulation changes (Piotrowski et al., 2004 EPSL), glacial–interglacial transitions (Piotrowski et al., 2005, Science), and glacial millennial-scale variability (Piotrowski et al., 2008, EPSL).

My research group at Cambridge is currently using radiogenic isotopes, including those of Nd and Pb, and elemental concentrations, in marine sediment samples at globally distributed sites to gain a wider view of past ocean geochemistry.  Our recent paper (Roberts et al., 2010, Science) was the first to compare past changes in water mass source and structure using Nd isotopes, to changes in the circulation strength using Pa-231/Th-230 from the Bermuda Rise (MacManus et al., 2004), and showed that millennial-scale and glacial-interglacial changes in ocean circulation had different dynamics. 


 

Ph.D. students –                     

David Wilson (2007 - present), utilizing Nd and Pb isotopes of Fe-Mn leachates and foraminifera to reconstruct deep Indian Ocean water mass chemistry and sourcing during the last two glacial cycles.  Also examining the chemical kinetics of Nd mobilization from marine sediments during acid reductive leaching of sediments (co-supervisor:  A. Galy)

Taryn Noble (2007 - present), reconstructing past changes in Southern Ocean sediment sourcing and flux using radiogenic (Sr, Nd, Pb) and U-series isotopes (co-supervisor N. McCave, in collaboration with L. Robinson WHOI and J. McManus LDEO)

Natalie Roberts (2008 - present), combining Nd isotopes and Pa/Th proxies to reconstruct North Atlantic deep water structure, source, and overturning strength (co-supervisor J. McManus LDEO, in collaboration with L. Keigwin and W. Curry WHOI) 

I am also co-supervising Oliver Shorttle (2009 - present), who is measuring Nd, Sr, and Pb isotopes on Icelandic samples to reconstruct deglacial changes in melt generation (primary supervisor is J. MacLennan)

 

Publications:

Roberts, N.L., Piotrowski, A.M., McManus, J., Keigwin, L., (2009) Synchronous deglacial overturning and water mass source changes, Science, 327 (5961). pp. 75-78.

Westbrook, G. K., Thatcher, K. E., Rohling, E. J., Piotrowski, A.M., Pälike H., Osborne A. H., Nisbet E. G., Minshull T. A., Lanoisellé M., James R. H., Hühnerbach V., Green, D., Fisher R. E., Crocker A. J., Chabert A., Bolton C., Beszczynska-Möller A., Berndt C., Aquilina A., (2009) Escape of methane gas from the seabed along the West Spitsbergen continental margin, Geophysical Research Letters, 36, L15608. 

Piotrowski, A.M., Banakar V. K., Scrivner A. E., Elderfield H., Galy A., and Dennis A.,  (2009)  Indian Ocean Circulation and Productivity during the Last Glacial Cycle, Earth and Planetary Science Letters 285, 179-189.

Yu J., Elderfield H., and Piotrowski, A.M. (2008) Seawater carbonate ion-d13C systematics and application to glacial–interglacial North Atlantic ocean circulation, Earth and Planetary Science Letters 271, 209-220.

Piotrowski, A.M., Goldstein, S.L., Hemming, S.R., and Fairbanks, R.G., and Zylberberg, D.R. (2008) Oscillating glacial northern and southern deep water formation from neodymium and carbon isotopes, Earth and Planetary Science Letters 272 394–405.

Kissel C., Laj C., Piotrowski A. M., Goldstein S. L., and Hemming S. R. (2008), Millennial-scale propagation of Atlantic deep waters to the glacial Southern Ocean, Paleoceanography, 23, PA2102, doi:10.1029/2008PA001624

Major, C.O., Goldstein, S.L., Ryan, W.B.F., Lericolais G., Piotrowski, A.M., Hajdas, I. (2006), “The co-evolution of Black Sea level and composition through the last deglaciation and its paleoclimatic significance”, Quaternary Science Reviews.

Piotrowski, A.M., Goldstein, S.L., Hemming, S.R., and Fairbanks, R.G., (2005) “Temporal relationships of carbon cycling and ocean circulation at glacial boundaries”, Science  307, 5717, 1933-1938. 

Piotrowski, A.M., Goldstein, S.L., Hemming, S.R., and Fairbanks, R.G., (2004) “Intensification and variability of ocean thermohaline circulation through the last deglaciation”, Earth and Planetary Science Letters 225, 205-220.

Bory, A., Biscaye, P. E., Piotrowski, A.M., and Steffensen, J. P., (2003) “Mineral dust composition in the Greenland ice sheet and its provenance: How uniform?”, Geochemistry Geophysics Geosystems, 4, 12, 2003GC000627.

Piotrowski, A.M., Lee, D.-C., Christensen, J.N., Burton, K.W., Halliday, A.N., Hein, J.R., and Gunther, D., (2000) “Changes in erosion and ocean circulation recorded in the Hf isotopic compositions of North Atlantic and Indian Ocean ferromanganese crusts”, Earth and Planetary Science Letters 181, 315-325.

 

Older Publications by Dr Alex Piotrowski


Publications: 2006-Present

Last updated on 22-Jun-10 09:21