Delta13C of particulate organic material in the Southern Ocean
Privatdozentin Dr. Uta Desy Elisabeth Passow
University of California Santa Barbara
Marine Science Institute
The purpose of this proposal is to identify the exact cause(s) of the anomalously low and variable Southern Ocean δ13Corg and in light of these assess the reliability of δ13C as a paleo-proxy. To effectively answer the proposal theme, main goals of our 3 year project were: (1) Identify the phytoplankton species primarily responsible for the light δ13Corg values observed in the Southern Ocean. (2) Identify possible conditions (size, growth environment) leading to the production of such light material. (3) Analyze the relationships between δ13Corg and other isotopic compositions (δ15N, δ30Si) which are used as paleo-proxies. (4) Assess the value of δ13Corg as a paleo-proxy in view of the above findings. Analysis of cruise data should be complete by the end of 2008/start of 2009. Culture experiments on Southern Ocean diatoms have begun, at different CO2 levels to assess impact on fractionation and uptake kinetics in collaboration with the Membrane Inlet Mass Spectrometry (MIMS) group at AWI. Furiher experiments with the MIMS are planned for 2009, as is analysis of the δ30Si samples collected on ANT-XXIV/3. Release of funds for the third year is requested to allow review of the main PhD goals in light of field and laboratory data in comparison with observations and analyses by other members of the bundle 'Trace elements and their isotopes in the Southern Ocean during the International Polar Year". A large amount of time will be spent on writing the thesis and publications.
Beteiligte Person: Professor Dr. Dieter Wolf-Gladrow, Ph.D.
term from 2007 to 2010