Final PhD Seminar: Threats to phytoplankton productivity in the antarctic marine ecosystem from a changing climate
Speaker: Katherina Petrou
Supervisor: Prof. Peter Ralph
The Antarctic marine ecosystem is unique and highly dynamic. It undergoes dramatic changes seasonally, involving the transition and changing proportion of specialised niche habitats including open ocean, sea ice and meltwater environments. Phytoplankton are key players in the structure and functioning of the Antarctic ecosystem, instrumental in the regions biogeochemical cycling, carbon provisioning to the food web, and major contributors to global primary production and carbon sequestration.
Understanding the physiological plasticity of Antarctic phytoplankton is essential to determining the effects that global change is likely to have on regional productivity. The ability for marine phytoplankton to acclimate rapidly to the changed conditions depends on the species’ physiology and plasticity.
This thesis investigated the processes of light acclimation, photoprotection and photoinhibition in Antarctic microalgae under different environmental stressors. It explored and compared the photophysiological strategies and responses of Antarctic phytoplankton from the sea ice, meltwater and pelagic habitats to environmental change. Heterogeneity in the photoprotective capacity amongst dominant Antarctic diatom species was revealed, providing new insight into links between ecological niche adaptation, species distribution and functioning.