Down Under(ground) – Introducing the Australian Critical Zone Observatory Network

The growing global network of Critical Zone Observatories provides exciting insights into how terrestrial and subsurface environments are interconnected, emphasising the value of understanding the Critical Zone as a vertically integrated system.  Yet this network is situated overwhelmingly in the frequently young and post-glacial or glacially-influenced landscapes of the Northern Hemisphere.  The Southern Hemisphere offers diverse landscapes with geologic parent materials spanning the Archaean to the Cenozoic, which have experienced little glaciation relative to the Northern Hemisphere.  The Australian Critical Zone Observatory Network was established in 2020 to provide insights into the structure and functioning of such landscapes on the ancient, chemically depleted, dry and diverse Australian continent. Five sites have been established with a common suite of instrumentation and operating principles, and are working collaboratively to develop Critical Zone datasets in landscapes ranging from rainforest to eucalyptus woodlands, dryland mallee, tropical savannah and rain-dependent agricultural lands.

This talk will introduce the OzCZO – the Australian Critical Zone Observatory Network, the five sites, their instrumentation and opportunities for scientific research within and by making comparisons among the sites.  It will then share some of the initial observations being collected at one of the observatories – the ancient lateritic landscape of the Avon Critical Zone Observatory.  We will illustrate how CZ structure, illuminated by bore logs and geophysics, organises soil physical and chemical properties across the landscape, and reveal how these properties then feed into land management decisions, hydrological functioning, and large-scale ecological health.  The Avon CZO is located within a biodiversity hotspot in the South-West of Australia, where the health of land and waters, and the ecosystems and agricultural production that depend on them, is threatened by both dryland salinity and a drying climate – with outcomes all mediated by the Critical Zone.

All data from OzCZO will be publicly available for use, and the sites are intended to act as an open platform where researchers can develop and test their ideas.  Given the scope for valuable cooperation and comparisons across these sites, we invite researchers at EGU to engage with OzCZO and keep progressing towards a global Critical Zone science.