Poster Presentation Australian Marine Sciences Association 2025 Conference

New sea-level reconstructions from southeastern Australia (#123)

Juliet Sefton 1 , Sophie Williams 2 , Liam Kruger 3 , Rafael Carvalho 4 , Ruth Reef 3 , Nicole Khan 5
  1. University of Melbourne, Carlton, VICTORIA, Australia
  2. Department of Geography, Durham University, Durham, United Kingdom
  3. School of Earth, Atmosphere, and Environment, Monash University, Clayton, Australia
  4. James Cook University, Townsville, Queensland, Australia
  5. University of Hong Kong, Hong Kong

Since the around the 1860s, global sea level has been rising – and accelerating – at a ‘unprecedented’ rate. This rise has been recorded by tide gauges and organic coastal sediment archives worldwide, and advances to understand how this rise manifests at regional to local scales are underway, particularly in the North Atlantic region. In Australia, the tide gauge record is short (mostly since 1950) and there are a limited number of sedimentary records that provide information on sea-level change. The records that do exist indicate the rate of rise in southeastern Australian exceeds the global average in the 20th century (e.g., Williams et al., 2023). We present two new sea-level reconstructions from southeastern Australia developed from saltmarsh foraminifera at King Island (Tasmania) and Venus Bay (Victoria). We develop chronologies for both sediment records using radiocarbon and lead isotopes. The fossil foraminifera assemblages at both sites indicate local sea-level rise over the past ~150 years. Spatial-temporal modelling of geological sea-level data highlights the contribution of local, regional, and global processes through space and time. This work fits into a larger effort to build a network of sedimentary sea-level records to determine a sea-level ‘budget’ in southeastern Australia.