Climate Change and Earth-Ocean-Atmosphere Systems.
Alexander Piotrowski is accepting applications for PhD students.
Alexander Piotrowski is available for consultancy.
Reconstructing the Ocean-Climate Link with Geochemical Tracers
The primary focus of my research is to understand the link between ocean circulation and climate over recent earth history. The global ocean overturning is an important component of the earth’s climate system because the deep ocean hosts a large reservoir of carbon dioxide that exchanges with the atmosphere on short timescales, and its circulation also transports heat across the face of the planet. 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.
My research group at Cambridge uses radiogenic isotopes, including those of Nd and Pb, and other geochemical tools, at globally distributed sites to gain a big picture view of past ocean geochemistry. A number of my studies have used Nd isotopes to examine South Atlantic deep water sourcing changes during glacial–interglacial transitions (Piotrowski et al., 2005, Science), and glacial millennial-scale variability (Piotrowski et al., 2008, EPSL). My research group is measuring Nd isotopes records at key locations in the deep ocean, including the the Atlantic (Piotrowski et al., EPSL 2012, Roberts et al., EPSL 2010, GCA 2012, Howe et al., Geology 2016) Indian Ocean (Piotrowski et al., EPSL 2009, Wilson et al., EPSL 2012) and Pacific (Noble et al., EPSL 2013, Hu et al., EPSL 2016). My research group also was the first to relate how past changes in water-mass source to changes in the circulation strength in the North Atlantic using neodymium isotopes and proxies of deep ocean circulation including 231Pa/230Th (Roberts et al., Science 2010), allowing a better understanding of the dynamics of past ocean circulation changes and its link to palaeoclimate changes. As a result of these studies a coherent picture of global thermohaline circulation changes during the last glacial cycle is emerging from our robust dataset (Howe et al., Nature Communications, 2016, Hu et al., EPSL 2016). We are also interfacing geochemical measurements of dissolved chemistry with that of detrital sediment to investigate past changes in terrestrial weathering, sediment input to the ocean, and transport within the ocean circulation system.
David Wilson (2007 – 2011), Nd and Pb isotopes to reconstruct deep Indian Ocean.
Taryn Noble (2007 – 2011), Southern Ocean sediment sourcing and flux.
Natalie Roberts (2008 – 2012), Nd isotopes and Pa/Th proxies in North Atlantic deep water.
Jake Howe (2011–2015), Reconstructing past changes in Atlantic Deep Water Circulation.
Rong Hu (2012 – 2017), Glacial-Interglacial changes in Pacific Nd and Pb isotopes.
Yuting Li (2012 – present), Sediment input and transport to the deglacial North Atlantic.
Thomas Williams (2012 – present), Glacial Southern Ocean circulation
Christina Larkin (2016 – present), North Atlantic Nd isotopes and weathering inputs
Geochemistry ; palaeoclimate reconstructions
All publications can be found in the publications database here
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., Fairbanks, R.G., 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.
Piotrowski A.M., Galy, A., Nicholl, J.A.L., Roberts, N.L., Wilson, D.J.,Clegg, J., and Yu, J., (2012), Reconstructing deglacial North and South Atlantic deep water source using foraminiferal Nd isotopes, Earth and Planetary Science Letters 357-358, 289-297.
Roberts, N.L., Piotrowski, A.M., McManus, J., Keigwin, L., (2010) Synchronous deglacial overturning and water mass source changes, Science, 327 (5961). pp. 75-78.
Howe J.N.W., Piotrowski, A.M., Mulitza, S., Noble T.L., Chiessi C.M., Bayon, G., (2016) North Atlantic Deep Water Production during the Last Glacial Maximum Nature Communications 7, 11765.
Hu, R., Piotrowski, A.M., Bostock, H.C., Crowhurst, S., Rennie V., (2016) Variability of Neodymium Isotopes associated with planktonic foraminifera in the Pacific Ocean, Earth and Planetary Science Letters 447, 130-138.
Henry, L.G., McManus, J.F., Curry, W.B., Roberts, N.L., Piotrowski A.M., Keigwin, L.D., (2016) North Atlantic ocean circulation and abrupt climate change during the last glaciation, Science, 353, 6298, 470-474.
Howe, J.N.W., Piotrowski, A.M., and Rennie V.C., (2016) Abyssal origin for the early Holocene pulse of unradiogenic neodymium isotopes in Atlantic seawater, Geology doi:10.1130/G38155.1