The dataset provides the spatially continuous data of the seabed gravel content (sediment fraction >2000 µm) expressed as a weight percentage ranging from 0 to 100%, presented in 0.01 decimal degree resolution raster format. The dataset covers the Australian continental EEZ, including seabed surrounding Tasmania. It does not include areas surrounding Macquarie Island, and the Australian Territories of Norfolk Island, Christmas Island, and Cocos (Keeling) Islands or Australia's marine jurisdiction off of the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. This dataset supersedes previous predictions of sediment gravel content for the Australian Margin with demonstrated improvements in accuracy. Accuracy of predictions varies based on density of underlying data and level of seabed complexity. Artefacts occur in this dataset as a result of insufficient samples in relevant regions. This dataset is intended for use at national and regional scales. The dataset may not be appropriate for use at local scales in areas where sample density is insufficient to detect local variation in sediment properties. To obtain the most accurate interpretation of sediment distribution in these areas, it is recommended that additional samples be collected and interpolations updated.

Seagrass communities in the northwest of Torres Strait are known to disappear episodically over broad areas. Sediment mobility surveys were undertaken within two study areas during the monsoon and trade wind seasons, in the vicinity of Turnagain Island, to find out if the migration of bedforms could explain this disappearance. The two study areas covered sand bank and sand dune environments to compare and contrast their migration characteristics. Repeat multibeam sonar surveys were used to measure dune-crest migration during each season.

This dataset contains species identifications of crinoids collected during survey SOL4934 (R.V. Solander, 27 August - 24 September, 2009). Animals were collected from the Joseph Bonaparte Gulf with a benthic sled. Specimens were lodged at Museum of Victoria on the 19 April 2010. Species-level identifications were undertaken by Kate Naughton at the Museum of Victoria and were delivered to Geoscience Australia in December 2010. See GA Record 2010/09 for further details on survey methods and specimen acquisition. Data is presented here exactly as delivered by the taxonomist, and Geoscience Australia is unable to verify the accuracy of the taxonomic identifications.

This record contains the substantive results of Geoscience Australia marine survey SS08/2005 to the SW margin of Australia. The survey was completed between 28 September and 20 October 2005 using Australia’s national facility research vessel Southern Surveyor. The survey included scientists from Geoscience Australia, CSIRO – Marine and Atmospheric Research, and Victoria Museum. The survey was co‐funded by Geoscience Australia and the Department of the Environment and Heritage (now the Department of the Environment, Water, Heritage and the Arts). The principal aims of the survey were to explore deep‐sea habitats and processes in submarine canyons on the SW margin, and examine the geology of the underlying Mentelle Basin as an assessment for its petroleum potential.

Understanding and predicting the bio-physical relationships between seabed habitats, biological assemblages, and marine biodiversity is critical to managing marine systems. Species distributions and assemblage structure of infauna were examined on the oceanic shelf surrounding Lord Howe Island (LHI) relative to seabed complexity within and adjacent to a newly discovered relict coral reef. High resolution multibeam sonar was used to map the shelf, and identified an extensive relict reef in the middle of the shelf, which separated an inner drowned lagoon from the outer shelf. Shelf sediments and infauna were sampled using a Smith McIntyre grab. The three geomorphic zones (drowned lagoon, relict reef and outer shelf) were strong predictors or surrogates of the physical structure and sediment composition of the LHI shelf and its infaunal assemblage. Infaunal assemblages were highly diverse with many new and endemic species recorded. Each zone supported characteristic assemblages and feeding guilds, with higher abundance and diversity offshore.

Disturbances characterise many natural environments - on land, a forest fire that removes a patch of old-growth trees is an example. The trees that first colonise the vacant patch may be a different species to the surrounding old-growth forest and hence, taken together, the disturbed and undisturbed forest has a higher biodiversity than the original undisturbed forest. This simple example demonstrates the intermediate disturbance hypothesis (IDH) that has applications in many natural environments. The application of IDH is significant for managers tasked with managing and conserving the biodiversity that exists in a given area. In this report we have used models of seabed sediment mobilisation to examine IDH for Australia's continental shelf environment. Although other disturbance processes may occur (eg. biological, temperature, salinity, anthropogenic, etc.) our study addresses only the physical disturbance of the seabed by waves and currents. Our study has shown that it is feasible to model the frequency and magnitude of seabed disturbance in relation to the dominant energy source (wave-dominated shelf, tide-dominated shelf or tropical cyclone dominated shelf). We focussed our attention on high-energy, patch-clearing events defined as exceeding the Shields parameter value of 0.25. Based on what is known about rates of ecological succession for different substrate types (gravel, sand, mud) we derive maps predicting the spatial distribution of a dimensionless ecological disturbance index (ED). Only a small portion of the shelf (perhaps ~10%) is characterised by a disturbance regime as defined here. Within these areas, the recurrence interval of disturbance events is comparable to the rate of ecological succession and meets our defined criteria for a disturbance regime. To our knowledge, this is the first time such an analysis has been attempted for any continental shelf on the earth.

A seabed mapping survey over a series of carbonate banks, intervening channels and surrounding sediment plains on the Van Diemen Rise in the eastern Joseph Bonaparte Gulf was completed under a Memorandum of Understanding between Geoscience Australia and the Australian Institute of Marine Sciences. The survey obtained detailed geological (sedimentological, geochemical, geophysical) and biological data (macro-benthic and infaunal diversity, community structure) for the banks, channels and plains to establish the late-Quaternary evolution of the region and investigate relationships between the physical environment and associated biota for biodiversity prediction. The survey also permits the biodiversity of benthos of the Van Diemen Rise to be put into a biogeographic context of the Arafura-Timor Sea and wider northern Australian marine region. Four study areas were investigated across the outer to inner shelf. Multibeam sonar data provide 100 per cent coverage of the seabed for each study area and are supplemented with geological and biological samples collected from 63 stations. In a novel approach, geochemical data collected at the stations provide an assessment of sediment and water quality for surrogacy research. Oceanographic data collected at four stations on the Van Diemen Rise will provide an understanding of the wave, tide and ocean currents as well as insights into sediment transport. A total of 1,154 square kilometres of multibeam sonar data and 340 line-km of shallow (<100 mbsf) sub-bottom profiles were collected.

High resolution multibeam bathymetry is used to map and interpret seabed geomorphology for part of the northern Lord Howe Rise plateau in the Tasman Sea. A mapping system of geomorphic units and elements is used, extending the previous hierarchy of geomorphic provinces and features used for the Australian margin. The mapped area covers ~25,500 km2 and incorporates broad ridges, valleys and plateaus. Superimposed on these features are clusters of volcanic peaks, smaller ridges, holes, scarps and aprons. An additional characteristic of the seabed in this area is an extensive network of polygonal furrows that cover the plateaus and the lower slopes of larger ridges. These furrows are formed in stiff, unconsolidated carbonate ooze that forms a near-continuous sediment cover across the area. Peaks are the only geomorphic feature not fully draped in pelagic ooze. The distribution of geomorphic units suggests strong controls from underlying geological structures. In water depths of 1400 m to 1600 m some peaks occur in clusters on ridges that sit above acoustic basement highs and volcanic intrusions. Elsewhere, broad plains and valleys slope to the southwest following the regional dip of the Lord Howe Rise plateau. In contrast, localised geomorphic elements such as moats and holes have likely explanation in terms of spatial variations in sedimentation rates in relation to bathymetric highs. Polygonal furrows are attributed to dewatering processes. The geomorphology of the seabed mapped in this study incorporates examples of forms that have not been previously mapped in such detail on the Australian margin. These are unlikely to be unique to the mapped area of the Lord Howe Rise and can be expected to occur elsewhere on the Rise and presumably on other parts of the Australian margin with a similar geological history.

This resource contains surface sediment data for Bynoe Harbour collected by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and Department of Land Resource Management (Northern Territory Government) during the period from 2-29 May 2016 on the RV Solander (survey SOL6432/GA4452). This project was made possible through offset funds provided by INPEX-led Ichthys LNG Project to Northern Territory Government Department of Land Resource Management, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The intent of this four year (2014-2018) program is to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline data that enable the creation of thematic habitat maps that underpin marine resource management decisions. The specific objectives of the survey were to: 1. Obtain high resolution geophysical (bathymetry) data for outer Darwin Harbour, including Shoal Bay; 2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for outer Darwin Harbour, including Shoal Bay; and 3. Collect tidal data for the survey area. Data acquired during the survey included: multibeam sonar bathymetry and acoustic backscatter; physical samples of seabed sediments, underwater photography and video of grab sample locations and oceanographic information including tidal data and sound velocity profiles. This dataset comprises the results of sediment oxygen demand experiments undertaken on seabed sediments. A detailed account of the survey is provided in Siwabessy, P.J.W., Smit, N., Atkinson, I., Dando, N., Harries, S., Howard, F.J.F., Li, J., Nicholas W.A., Picard, K., Radke, L.C., Tran, M., Williams, D. and Whiteway, T., 2016. Bynoe Harbour Marine Survey 2017: GA4452/SOL6432 Post-survey report. Record 2017/04. Geoscience Australia, Canberra. Thanks to the crew of the RV Solander for help with sample collection, Matt Carey, Craig Wintle and Andrew Hislop from the Observatories and Science Support at Geoscience Australia for technical support and Jodie Smith for reviewing the data. This dataset is published with the permission of the CEO, Geoscience Australia

This resource contains surface sediment data for Bynoe Harbour collected by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and Department of Land Resource Management (Northern Territory Government) during the period from 2-29 May 2016 on the RV Solander (survey SOL6432/GA4452). This project was made possible through offset funds provided by INPEX-led Ichthys LNG Project to Northern Territory Government Department of Land Resource Management, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The intent of this four year (2014-2018) program is to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline data that enable the creation of thematic habitat maps that underpin marine resource management decisions. The specific objectives of the survey were to: 1. Obtain high resolution geophysical (bathymetry) data for outer Darwin Harbour, including Shoal Bay; 2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for outer Darwin Harbour, including Shoal Bay; and 3. Collect tidal data for the survey area. Data acquired during the survey included: multibeam sonar bathymetry and acoustic backscatter; physical samples of seabed sediments, underwater photography and video of grab sample locations and oceanographic information including tidal data and sound velocity profiles. This dataset comprises total chlorin concentrations, chlorin indices and porosity measured on seabed sediments. A detailed account of the survey is provided in Siwabessy, P.J.W., Smit, N., Atkinson, I., Dando, N., Harries, S., Howard, F.J.F., Li, J., Nicholas W.A., Picard, K., Radke, L.C., Tran, M., Williams, D. and Whiteway, T., 2016. Bynoe Harbour Marine Survey 2017: GA4452/SOL6432 Post-survey report. Record 2017/04. Geoscience Australia, Canberra. Thanks to the crew of the RV Solander for help with sample collection, Matt Carey, Craig Wintle and Andrew Hislop from the Observatories and Science Support at Geoscience Australia for technical support and Jodie Smith for reviewing the data. This dataset is published with the permission of the CEO, Geoscience Australia