Southern ocean nutrients and their links to climate change: insights from the elemental and isotope signature of diatoms

Diatoms are an important primary producer group and currently account for 40% of global primary production. The sequestration of carbon into the deep ocean by diatoms makes them key players in the modulation of atmospheric CO2 levels and global climate.

There is growing evidence from both laboratory and field experiments to show that zinc is actively involved in modulating the uptake of CO2 in marine diatoms via the enzyme carbonic anhydrase.

The overarching objective of this project is too to reconcile our evolving understanding of the role zinc plays in controlling diatom production in Southern Ocean waters, and how this relates to their ability to sequester and export CO2 from surface waters.

Specific objectives:

  1. Investigate the factors that influence zinc acquisition and use by diatoms and how this manifests through to pCO2 uptake, organic matter formation and frustule building.
  2. Determine the role iron limitation has on the cycling of zinc and silicon in the Southern Ocean surface waters and how this relates to the global distribution these two elements via mode and intermediate water export to low latitude.
  3. Constrain the poorly understood importance of the cadmium in the Southern Ocean, its relevance to diatoms production when zinc and iron concentrations are low, and how it relates to pCO2 uptake, organic matter formation and carbon export to the deep ocean.

Project funds are available. If you are interested in the project please contact