IMAS Metadata Catalogue
2020
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Declining atmospheric CO2 concentrations are considered the primary driver for the Cenozoic Greenhouse-Icehouse transition, ~34 million years ago. A role for tectonically opening Southern Ocean gateways, initiating the onset of a thermally isolating Antarctic Circumpolar Current, has been disputed as ocean models have not reproduced expected heat transport to the Antarctic coast. Here we use high-resolution ocean simulations with detailed paleobathymetry to demonstrate that tectonics did play a fundamental role in reorganising Southern Ocean circulation patterns and heat transport, consistent with available proxy data. When at least one gateway (Tasmanian or Drake) is shallow (300 m), gyres transport warm waters towards Antarctica. When the second gateway subsides below 300 m, these gyres weaken and cause a dramatic cooling (average of 2–4°C, up to 5°C) of Antarctic surface waters whilst the ACC remains weak. Our results demonstrate that tectonic changes are crucial for Southern Ocean climate change and should be carefully considered in constraining long-term climate sensitivity to CO2.
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A numerical ocean model based on the Regional Ocean Modelling System (ROMS) framework was run for the Sorsdal ice shelf region and included modifications for ice/ocean thermodynamics and mechanical pressure, following (Dinniman et al., 2007). The model domain was discretised on a polar stereographic grid with a uniform 2 km horizontal resolution. The vertical terrain-following coordinate had 31 vertical layers with a sigmoidal layer distribution to provide higher vertical resolution at the surface and bottom regions.
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Ecosystem data was collected as part of an integrated study of the continental shelf over a 2 and a half year period between November 2015 and January 2018. Data were collected bi-monthly through the spring to autumn (November, January, March, May). Stations were situated perpendicular to shelf bathymetry, ranging in depth from ~50 m to 100 m near the edge of the shelf and were located between 5 km and 15 km from land; encompassing from south Storm Bay, past the southern tip of Bruny Island and into the Southern Ocean (south-east Tasmania, Australia). Data collected focused on each trophic level, characterizing the zooplankton community, fish schools and marine predators. The overarching aim of the study was to investigate the effects of long term warming, and a marine heatwave event on zooplankton dynamics in terms of community response variables and the flow-on effects of changing lower-trophic level dynamics for top predators.
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Voyage IN2019_V04 contributed an additional 29,000 kms2 of seafloor survey data to the Coral Sea knowledge base. From this new bathymetric data individual seamounts have been extracted and have been classified to the Geoscience Australia Geomorphology Classification Scheme. This dataset contains two layers representing the classification layers- 1) Surface (Plain, Slope, Escarpment) and 2) fine scale Geomorphology of the seamount for the Calder Seamount. Ongoing research with this survey data will provide new insights into the detailed geomorphic shape and spatial relationships between adjacent seabed features. This information will be released in future publications to show the potential of how the scale of such seafloor data can be used for predictive habitat modelling when analysed with the biological data overlays.
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This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Synthesis Study - "Interpreting pressure profiles". For specific data outputs from this project, please see child records associated with this metadata. -------------------- This project has two objectives: (i) provide a spatial explicit analysis of the relative risks posed to marine conservation values, as defined by the natural values hierarchy of Parks Australia's Monitoring, Evaluation, Reporting and Improvement (MERI) framework, by pressures that operate within Australia's Exclusive Economic Zone and state/territory waters (a "hotspot" analysis); and, (ii) provide a proof of concept of an adaptive, probabilistic assessment of the cumulative risks posed to these values, in a region determined to support the Parks Australia MERI project D7, in a manner that is consistent with the seascape-scale cumulative assessment described in the "Guidelines for analysis of cumulative impacts and risks to the Great Barrier Reef". Planned Outputs • National hotspot maps of risks posed to marine conservation values • Probabilistic assessment (written) of cumulative risks
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The AUStralian Tidal Energy (AUSTEn) project was a three year project (2018 - 2020) funded by the Australian Renewable Energy National Agency (agreement number G00902) led by the Australian Maritime College (University of Tasmania), in partnership with CSIRO and University of Queensland. The project had a strong industry support (Atlantis Resources Limited, MAKO Tidal Turbines Ltd, Spiral Energy Corporation Ltd). The aim of the project was to assess the technical and economic feasibility of tidal energy in Australia, based on the best understanding of resource achievable. For further information and output of the project, please visit the AUSTEn project website www.austen.org.au.
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The Australian Coastal Restoration Network (ACRN) database collates information about coastal restoration projects in eight different ecosystems across Australia and New Zealand: shellfish, macroalgae, seagrass, mangrove, saltmarsh, coastal wetland and coral environments. This record represents a static snapshot of the database made in March 2020. The ACRN website (https://www.acrn.org.au) may contain more recent updates to the database.
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Achived photoquadrats are available from Reef Life Survey (RLS) surveys undertaken before and after a 2016 bleaching event at all major coral reef systems in Australia. This collection was analysed by experts to annotate coral cover to the highest possible taxonomic resolution for ~40,000 images. Specific Australian Marine Parks included are Ashmore Reef, Mermaid Reef and Coral Sea. NOTE: The high resolution coral taxonomic identification data has been assimilated into the larger global RLS photoquadrats data collection, currently held by AODN. This data is intended to be published before the end of 2020. Once published, the subset of annotation data generated by this project will be published as an excerpt attached to this record.
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Voyage IN2019_V04 contributed an additional 29,000 kms2 of seafloor survey data to the Coral Sea knowledge base. From this new bathymetric data individual seamounts have been extracted and have been classified to the Geoscience Australia Geomorphology Classification Scheme. This dataset contains two layers representing the classification layers- 1) Surface (Plain, Slope, Escarpment) and 2) fine scale Geomorphology of the seamount for the Mellish Seamount. Ongoing research with this survey data will provide new insights into the detailed geomorphic shape and spatial relationships between adjacent seabed features. This information will be released in future publications to show the potential of how the scale of such seafloor data can be used for predictive habitat modelling when analysed with the biological data overlays.
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This record contains: 1. Thesis 2. The MATLAB codes of the adaptive Canny gradient-based edge detection algorithm and calculating frontal probability/density (for AVHRR data and MODIS data separately). 3. Frontal probability (probability of frontal encounter, PFE) and frontal density (FD) data over Australian hotspot regions (for AVHRR data and MODIS data separately) 4. Results of the Mann-Kendall trend test The purpose of this study is to verify the regional trends of frontal activity within the two marine hotspots near Australia and compare the performance of the two edge detection algorithms.