Divergence in temperature stress management between coastal and East Australian current (EAC) phytoplankton populations.
In June 2015, 27 scientists took part in a 3 week ocean voyage aboard the brand new Australian research vessel, the RV Investigator. The main objective of the expedition was to study sub-mesoscale processes - billows and eddies - along the productive shelf influenced by the East Australian Current. Dr Olivier Laczka is presenting the results obtained for one of the multiple projects conducted during this voyage. Microbial communities from the EAC and a coastal site (north of Smokey Cape) were incubated along a temperature gradient (spanning 32 to 15.5 °C) to examine their capacity to deal with departures from in situ temperature (~22 °C). Intracellular stress within picoeukaryote populations was examined using a fluorescent stain targeting Reactive Oxygen Species (ROS). Stained samples were examined with a flow cytometer (excitation wavelength 488 nm). The goal of this study was to assess whether EAC microbial communities are more thermally tolerant than coastal microbial communities and determine whether general oxidative stress patterns could be used as a signature of water mass origins.