Annie Bourbonnais

I am the co-chief scientist on P18, leg 1. My research involves two main components. First, I am in charge of He (helium) and T (tritium) sampling on-board. He is an inert and conservative gas. We can use the volcanic isotopic signature of He, which has a higher ³He/⁴He than the atmosphere, as a tracer of ocean mixing and circulation. Furthermore, we can use both ³He and T as a dating tool to determine the ventilation time-scale for water masses (from a month to a few decades). 

Second, I am interested in using dissolved gases and nitrogen stable isotopes to elucidate nitrogen cycling in the ocean, particularly, in Oxygen Deficient Zones (ODZs). During this cruise, I will be collecting samples for determining the concentrations and isotopic compositions of dissolved O₂, N₂ and Ar, as well as NO₃^- and NO₂^- (both d¹⁵N and d¹⁸O).  I will also be collecting samples for N₂O isotope and isotopomer analysis. N₂O is a potent greenhouse gas and its isotope and isotopomer composition will inform us about production processes.