PhD Student

Delphi Ward


Evaluating the likelihood of critical transitions in Southern Ocean ecosystems

Effective ecosystem-based management requires that we manage for potential future ecosystem dynamics as well as current dynamics. This is made more challenging if the potential dynamics of a system include a critical transition – a sudden shift from one stable state to another. Critical transitions, or regime shifts, have occurred in a number of marine ecosystems in recent decades, often with devastating consequences for the people and species that depend on those ecosystems. In the Southern Ocean changes have occurred at multiple levels of the ecosystem in the recent past – due to environmental change and human activities – but there is not yet evidence that these changes constitute regime shifts. My project will address two components of this problem: 1) the detection of regime shifts and 2) evaluating the susceptibility of Southern Ocean ecosystems to critical transitions. Firstly, I am developing a method for detecting regime shifts from sparse data collected on repeat transects (e.g. Southern Ocean Continuous Plankton Recorder data). I am particularly interested in the role of feedback loops in ecosystem dynamics. So the second part of my PhD, will explore large-scale feedback loops in Southern Ocean ecosystems with the aim of evaluating the likelihood of ecological tipping points.



Dr Jessica Melbourne-Thomas

Professor Mark Hindell
Dr. Simon Wotherspoon
Professor Craig Johnson


Authorised by the CEO of the Antarctic Climate and Ecosystems Cooperative Research Centre October 2019.

The ACE CRC was established and supported under the Australian Government’s Cooperative Research Centres Program.

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