Research Student 2011
Climate Change and Earth-Ocean-Atmosphere Systems
Project Title: Pluri-Proxy Reconstruction of Quaternary Atlantic Ocean Circulation; Constraining the Use of Neodymium Isotopes as a Water Mass Trace.
Project Description: The circulation patterns of the deep Atlantic Ocean are thought to play an important part in the climate system. Exactly how this circulation has varied throughout the past is not, however, well understood. Various paleoceanographic proxies, which are usually chemical measurements made on certain phases of deep-sea sediments, have been measured on sediment cores from throughout the Atlantic to try and improve this understanding. These proxies suffer from various limitations, including being susceptible to changes external to ocean circulation, for example changes in the carbon cycle may affect the δ13C of benthic foraminifera. To overcome these limitations radiogenic isotopes with residence times in the ocean on the order of water mass mixing have been employed as water mass tracers. One such element used for this purpose is the rare earth element neodymium, which can be extracted from the coatings of foraminifera preserved in sea floor sediments.
My research focusses on increasing our understanding changes in Atlantic Meridional Overturning Circulation since the Last Glacial Maximum through the measurement of new neodymium records from both the eastern and western Atlantic Ocean. In conjunction to this I will be measuring lead isotopes, which are thought to have a shorter residence time in the ocean, in an effort to distinguish more localised chemical inputs. Contrasting these two proxies should aid in improving our understanding of both ocean circulation as well as how neodymium behaves in sea water and thus how it can be used as a water mass tracer.
Supervisor: Alex Piotrowski