Antarctic Bottom Water production in the past: Records from marine sediments, East Antarctica

Understanding past changes in Antarctic Bottom Water production to help predict how a warming climate will impact future ocean circulation.
Voyage No


25 Jan, 2023


02 Mar, 2023




Chief Scientist

Dr Alix Post


Geoscience Australia

Voyage summary

Research voyage from Fremantle to Hobart, traveling to the East Antarctic margin to investigate past changes in Antarctic Bottom Water (AABW) revealed by seafloor sediment records.

The voyage (called 'CANYONS') has two main scientific objectives: 1) to understand past changes in AABW production by collecting long sediment cores from the seafloor that span multiple climate periods; and, 2) develop an improved bathymetry (seafloor mapping) model to support oceanographic modelling of AABW pathways. Sediment core records of previous warmer interglacials (when Antarctic air temperatures were 2 to 4.5°C warmer than today) will provide an analogue for understanding the impact of any future changes in AABW production associated with a warming climate.

Proposed voyage track from Fremantle-Antarctica-Hobart.

Scientists will recover long sediment cores from the continental slope off Cape Darnley, East Antarctica. These will provide palaeoceanographic records over multiple glacial-interglacial cycles. This research will combine sedimentological, geochemical and biological proxies (variables that can be used to infer climate) as evidence of the nature and timing of past changes in AABW production, and associated variations in meltwater input, and the extent of the Cape Darnley polynya (open water surrounded by sea ice).

AABW has previously been associated with unique and diverse benthic (seafloor) ecosystems, including hydrocorals. Scientists will use a deep tow camera to investigate the presence and distribution of hydrocorals, and, if present, analyse their carbonate skeletons to understand past water mass variability over recent centuries, complementing sediment core records. The seafloor biodiversity assessment will provide information for future management of the proposed East Antarctica Marine Protected Area . The voyage has been approved as GEOTRACES Process Study

There are 8 other projects on this voyage:

  • #Sea2SchoolAU Education Program: bringing at-sea science into Australian classrooms via live video broadcasts during the voyage (Ms Joline Lalime, Education Queensland)
  • Evolution of marine life in Antarctica: extracting DNA from phytoplankton samples from the ancient sea floor: (Dr Linda Armbrecht , UTAS)
  • Trace metal sampling for micronutrient distributions: study of processes controlling distribution of trace metals in Antarctic waters (Dr Taryn Noble and Prof Zanna Chase , UTAS)
  • Argo and other float deployments: deployment of 7  standard and 2 biogeochemical (BGC) Argo floats, as well as 2 AAPP ice floats (Dr Kathy Gunn, CSIRO)
  • Organic aerosol characterisation in the Southern Ocean: study of aerosols over the Southern Ocean (Dr Holly Winton, Victoria University of Wellington and Dr Ruhi Humphries, CSIRO – on shore)
  • Assessment of marine biodiversity in the Southern Ocean using environmental DNA: analysis of metazoan biodiversity via eDNA sampling (Dr Leonie Suter, AAD – on shore)
  • Deep ocean camera: unique study of seafloor biota via deep ocean camera attached to CTD instrument (Dr Andy Carroll, GA)
  • Natural iron fertilization of oceans around Australia: research linking terrestrial dust and bushfires to marine biogeochemistry (Prof Andrew Bowie , UTAS on shore). 

The voyage will be led by Chief Scientist Dr Alix Post from Geoscience Australia . It is being delivered in partnership with the University of Queensland, University of Tasmania and Australian National University, in collaboration with other Australian and international universities and CSIRO.

Chief Scientist and Principal Investigator profiles are provided in the Voyage Gallery.

The science team on this voyage includes 35 participants from 9 institutions, including one international and 5 Australian universities. The voyage is also being supported by the ARC Australian Centre for Excellence in Antarctic Science (ACEAS).

COVID Protocols

To safeguard the health and well-being of participants, strict COVID protocols apply to all activities on this voyage. This includes a 5-day quarantine on shore and 2-phase PCR testing of all participants for COVID prior to boarding the vessel.

Voyage outcomes

A summary of voyage outcomes will be published approximately 3-6 months after the completion of the voyage.