Project Title: The biogeochemical role of diatoms in Australia’s coastal ocean
Supervisor: Dr Martina Doblin
PhD conferred: 2017
Email contact: Martina.Doblin@uts.edu.au
Diatoms may be considered the snowflakes of the sea, as their exquisite cytoarchitecture of glass distinguishes them from other phytoplankton groups. These organisms form an integral component of marine ecosystems, as they carry out approximately one-fifth of photosynthesis on Earth and dominate the phytoplankton assemblages that underpin our commercial fisheries. These microorganisms form their delicate, ornate cell walls from silica, an element derived from the weathering of rocks. Alterations in rainfall due to climate change may therefore have significant consequences for coastal phytoplankton productivity around Australia.
Laboratory studies have not been able to clearly show how diatoms and other phytoplankton functional groups will respond to Australia’s changing oceans, as observed responses under controlled conditions may not be reflective of their behaviour in natural systems. For example, recent research has shown wild-type strains of cyanobacteria are able to assimilate nitrate where cultured strains could not.
To address this knowledge gap, my project aims to gain an in-depth understanding of the biogeochemical functioning of diatoms in different regions of Australia’s coastal ocean. I will measure phytoplankton mediated biogeochemical transformations of carbon, nitrogen and silica in the coastal zone, with the data being taken up into biogeochemical models currently being developed by CSIRO.