IMAS Metadata Catalogue
2020
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The Indonesian Throughflow (ITF) is connects the Pacific Ocean and the Indian Ocean in the tropics. The ITF plays an essential role in ocean circulation and regional climate: it hosts strong mixing that can change water-mass properties, influences the sea surface temperature in both oceans and affects the global ocean volume and heat transports. The ITF transports water properties across Indonesian Seas characterized by complex topography with most of the water entering through two main inflow straits, Makassar and Lifamatola straits, and exiting into the Indian Ocean through three main outflow straits, Ombai, Lombok and Timor straits. The ITF shows variabilities on different time scales, including decadal, interannual, seasonal and intra-seasonal. The ITF variability on intra-seasonal time scales is driven by remotely generated Kelvin and Rossby waves that propagate into the Indonesian Seas from the Indian Ocean and Pacific Ocean. This project focuses on the variability driven by Kelvin waves that propagate into Indonesian seas through three main outflow straits (Ombai, Lombok and Timor). We use a global ocean model and a high-resolution regional ITF model to characterize these variabilities at different depths and in different straits. We also use the mooring observations from the INSTANT program to validate the ocean models.
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This resource includes bathymetry data for Elizabeth and Middleton Reef within Lord Howe Marine Park collected by Geoscience Australia during the period 31 January to 6 February 2020 on the Australian Maritime College vessel, TV Bluefin. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with the Institute for Marine & Antarctic Studies (University of Tasmania), NSW Department of Primary Industries, University of Sydney (Centre for Field Robotics) and Parks Australia. The purpose of the survey was to collect baseline information for benthic habitats within the National Park Zone (Middleton Reef) and Recreational Use Zone (Elizabeth Reef) of the marine park. These data will support ongoing environmental monitoring within the Temperate East Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included seabed mapping using multibeam sonar (Kongsberg EM 2040C HD, 300 kHz), seabed imagery acquisition by Autonomous Underwater Vehicle (AUV Sirius), sediment samples (grab) and imagery of demersal fish communities by baited remote underwater video (BRUV). This dataset comprises two bathymetry grids derived from multibeam sonar data gridded at 5 m spatial resolution, covering a combined area of 312 km2 including the transit. A detailed report on the survey is provided in: Carroll, A et al. 2020. Australian Marine Park Baseline and Monitoring Survey: Post Survey Report, Middleton and Elizabeth Reefs, Lord Howe Marine Park. Report to the National Environmental Science Program, Marine Biodiversity Hub. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia
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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 Sula 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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Trace element (TE) concentrations of juvenile Short-tailed Shearwaters collected on Great Dog Island, Tasmanian in 2017.
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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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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 Fregetta 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 - "National trends in coral species following heatwaves". For specific data outputs from this project, please see child records associated with this metadata. -------------------- This project engaged coral taxonomic experts to annotate existing Reef Life Survey (RLS) photoquadrats taken across northern Australia before and after major disturbances, to allow: • Quantification of the spatial and species-level responses of Australian corals to the 2016 and 2017 marine heatwave and mass bleaching events (and cyclones that occurred during this period). • Identification of the species most threatened by warming and cyclones, and species likely to respond best to restoration efforts. • Contribution to a coral-specific analysis to the next national State of the Environment report. Planned Outputs • Dataset on % cover of corals to highest taxonomic resolution possible from surveys around northern Australia before and after the 2016 mass bleaching event.
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Ocean currents are strongly controlled by seafloor topography. Recent studies have shown that small-scale features with slopes steeper than 0.05° significantly affect subsurface eddy velocities and the vertical structure of ocean circulation patterns. Such slope gradients represent the majority of the present-day oceanic basins. Modeling past oceanographic conditions for key climate stages requires similarly detailed paleo seafloor topography grids, in order to capture ocean currents accurately, especially for ocean models with sufficient resolution (<0.1°) to resolve eddies. However, existing paleobathymetry reconstructions use either a forward modeling approach, resulting in global grids lacking detailed seafloor roughness, or a backward modeling technique based on sediment backstripping, capturing realistic slope gradients, but for a spatially restricted area. Both approaches produce insufficient boundary conditions for high-resolution global paleo models. Here, we compute high-resolution global paleobathymetry grids, with detailed focus on the Southern Ocean, for key Cretaceous and early Cenozoic climate stages. We backstrip sediments from the modern global bathymetry, allowing the preservation of present-day seafloor slope gradients. Sediment isopach data are compiled from existing seismo-stratigraphic interpretations along the Southern Ocean margins, and expanded globally using total sediment thickness information and constant sedimentation rates. We also consider the effect of mantle flow on long-wavelength topography. The resulting grids contain realistic seafloor slope gradients and continental slopes across the continent-ocean transition zones that are similar to present-day observations. Using these detailed paleobathymetry grids for high-resolution global paleo models will help to accurately reconstruct oceanographic conditions of key climate stages and their interaction with the evolving seafloor.
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This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Project A15 - "Conservation status of tropical inshore dolphins". No data outputs are expected for this project. -------------------- This project is solely for a desktop review of peer-reviewed publications, research projects, and reports (e.g. EIAs) associated with major port developments 2013-2019.
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The final lithospheric breakup of the Australian-Antarctic rift system remains controversial due to sparse geological constraints on the nature of the basement along the ocean-continent transition zones. We present new interpretations of multichannel seismic reflection transects, as well as new petrological data of dredged mantle rocks along the East Antarctic margin (Seamount B, offshore Terre Adélie). By combining both datasets, we show that a 50–100 km wide domain of cold (900°C), fertile subcontinental mantle was exhumed along the non-volcanic Antarctic margin. The dredged peridotites preserve characteristics similar to mantle xenoliths found in syn- to post-rift volcanism at the eastern end of the Australian margin (Victoria and Tasmania), indicating the sampling of a common fertile subcontinental mantle during rifting between Australia and Antarctica. Seamount B represents the initial stages of exhumation of cold subcontinental lithosphere along an ocean-continent transition during rifting. This thick mantle domain was likely affected by syn-rift melt impregnation at high-pressure (8 kbar), leading to the formation of plagioclase-pyroxenites. Overall, the combination of continental rifted blocks, a 50-100 km wide domain of volcanic-poor subcontinental mantle and (ultra)-slow spreading implies that ocean-continent transition zones along the Australian-Antarctic margins represent a recent analogue to ocean continent transition zones from the Jurassic Western Tethys. Additionally, evidence of syn-rift melt stagnation at high pressure suggests that magmatism along the Australian-Antarctic rifted margins was sufficient to form magnetic anomalies that can be used as isochrons despite their formation in lithosphere other than mature, steady-state ocean crust.