IMAS Metadata Catalogue
2020
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We utilize the sea level fingerprint module - ISSM’s Solid Earth and Sea level Adjustment Workbench (ISSM-SESAW), developed by NASA/Jet Propulsion Laboratory (JPL), to provide high-resolution sea level fingerprints in response to future polar ice sheet mass changes in the 21st century under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. We also explore the sensitivity of sea level fingerprints to different 1-D elastic Earth models and the spatial resolution at which mass change of polar ice sheets is resolved. Furthermore, sea level contributions by individual polar ice sheet basins in the 21st century are also estimated for some coastal cities of interest (e.g., Perth) in this research.
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This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Project E3 - "Microplastics in the Australian marine environment". No data outputs are expected for this project. -------------------- A literature review will firstly identify key marine microplastics research and policy development internationally, with a focus on research that is contextual to microplastics in the Australian marine environment From this literature review, an options paper will be developed to explore the most feasible and impactful policy approaches for the Australian context to reduce both intentionally added and not intentionally added microplastics in the marine environment (it would be beneficial to understand the policy options that can address both categories of microplastics because the options are different). These two reports would form the basis of a one day workshop that will draw together policy-makers, researchers and relevant industry peak bodies to discuss and recommend policy and other options to limit the release / impact of microplastics in the environment. A workshop report will be drafted to summarise findings, recommendations, and next steps (including identifying gaps in both science and policy will inform any future work required). The report will provide evidence to underpin the development of national policy aimed at reducing microplastic pollution, including by identifying priority actions to deliver Australia’s 2018 National Waste Policy .
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This record describes an aggregated data product compiled from a number of different surveys of Macrocystis surface cover in Tasmanian waters, spanning 1950 to 2019. Some surveys represent a statewide census of Macrocystis cover, while others are targeted surveys of smaller regions. Methodology and data quality may also vary between surveys. Please see linked metadata records for specific methodologies and quality statements applying to individual surveys.
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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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Mapping of benthic habitat and seafloor bathymetry of Lancelin, WA derived from satellite imagery captured on 17 July 2017 at a spatial resolution of 2 m. Mapping extent covered as much of the Defence gazetted waters as possible, to a depth of approximately 18 m based on water clarity. Recently dead or senesced (e.g. winter dieback of leaves) and mobile seagrass have the same satellite signature as live seagrass at spectral resolutions of the sensor (WorldView-2). This ensured areas of winter dieback and/or senescence were captured as areas of seagrass for the purposes of impact assessment.
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This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Project D8 - "Canyon mapping & biodiversity in Gascoyne Marine Park". For specific data outputs from this project, please see child records associated with this metadata. -------------------- Very little is known about the deep waters of Australia’s marine parks. Recent NESP-supported surveys have targeted eastern abyssal depths and Tasmanian seamounts (NESP Project D4), but there have been no similar efforts in Western Australia. To counter this information deficit, we plan to actively map and sample two significant and biologically unexplored submarine canyons (Cape Range and Cloates Canyon) in the habitat protection and multiple use zones of the Gascoyne Marine Park. Standard operating procedures for marine sampling (multibeam, survey design) will be followed, with other sampling platforms (e-DNA, ROV) informing future SOPs (NESP Project D2). Planned Outputs • ROV image library (to be archived with the Australian Marine Imagery Collection at NCI) • Derived bathymetric products (to be made available through Geoscience Australia website and linked to relevant portals, including the Marine Park Atlas and North-West Atlas) • Taxonomic identifications and associated metadata (to be made available online through Atlas of Living Australia (ALA) web portal) • Sanger genetic sequences and e-DNA sequences (to be lodged in databases such as NCBI’s Genbank, short read archive or DataDryad) • Multibeam data will be processed into bathymetric grids at Geoscience Australia and made available via the AusSeabed portal
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2019-20 Honours project - Environmental Drivers of Antarctic Landfast Sea Ice Formation and Breakout
Antarctic Landfast sea ice (fast ice) is important climatologically, biologically and for logistics for short time-scale anomalies. Until recently, there hasn’t been an accurate, high-resolution fast ice extent dataset which can support an analysis on drivers of fast ice and most studies only investigate fast ice on limited regions of Antarctica in a limited time scale. There is a need to extend the spatial and temporal studying coverage to provide detailed information on the Antarctic coast over a longer period. This is the first detailed analysis to identify and quantify correlation between the environmental anomaly and fast ice anomaly mainly in the east Antarctic coast. By examining regional/local fast ice extent in in east Antarctic coast in the context of the broader and/or remote-teleconnected atmospheric circulation/properties using spatial correlation techniques, a strong correlation between NINO3 region and Lützow-Holm Bay fast ice and similar and significant correlation of regional scale factors from Lützow-Holm Bay to Mawson Coast mainly are found. The results of this thesis suggest that the pack ice, atmospheric factors and oceanic factors are important for interpreting fast ice anomalies. To identify and quantify correlation between the pack ice, temperature at 2m, wind at 10m, snow fall anomaly, sea surface temperature anomaly, ocean heat content anomaly and fast ice anomaly, backward multiple linear regression is conducted to demonstrate some predictive fast ice driver information by quantifying the correlation between different drivers and fast ice anomaly. The multiple linear regression also suggests that oceanic influences including pack ice are generally more important than atmospheric influences. Future experiments could be conducted to interpret fast ice anomalies in the context of the ocean mainly.
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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.
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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.
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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.