National seascapes describing a layer of ecologically-meaningful biophysical properties that spatially represent potential seabed habitats have been derived for the Australian margin and adjacent seafloor. Seascapes were derived separately for the shelf and off-shelf regions due to different data availability. A total of 13 and 9 seascapes were derived for the on-shelf and off-shelf regions, respectively, using the unsupervised ISOCLASS classification in the software package ERMapper. Generally, the on-shelf seascapes divide into two broad latitudinal groups. The southern group (seascapes 1-7) is characterised by sandy, cooler environments relative to the northern group (seascape 9-13) which is characterised by muddier, warmer environments. Seascape 8 occurs predominantly on the west and east margins, separating the two groups. Off-shelf seascapes lack a distinct latitudinal pattern and their distribution is more related to seafloor temperature as a function of depth. For the deep-sea regions on the southern and western margins the seascapes are principally defined by rugosity and primary production. For other areas off-shelf seascape distribution is more complex and related to bathymetry and slope (rugosity).

National seascapes describing a layer of ecologically-meaningful biophysical properties that spatially represent potential seabed habitats have been derived for the Australian margin and adjacent seafloor. Seascapes were derived separately for the shelf and off-shelf regions due to different data availability. A total of 13 and 9 seascapes were derived for the on-shelf and off-shelf regions, respectively, using the unsupervised ISOCLASS classification in the software package ERMapper. Generally, the on-shelf seascapes divide into two broad latitudinal groups. The southern group (seascapes 1-7) is characterised by sandy, cooler environments relative to the northern group (seascape 9-13) which is characterised by muddier, warmer environments. Seascape 8 occurs predominantly on the west and east margins, separating the two groups. Off-shelf seascapes lack a distinct latitudinal pattern and their distribution is more related to seafloor temperature as a function of depth. For the deep-sea regions on the southern and western margins the seascapes are principally defined by rugosity and primary production. For other areas off-shelf seascape distribution is more complex and related to bathymetry and slope (rugosity).

In May 2013, Geoscience Australia (GA) and the Australian Institute of Marine Science (AIMS) undertook a collaborative seabed mapping survey (GA0340/ SOL5754) on the Leveque Shelf, a distinct geological province within the Browse Basin, offshore Western Australia. The purpose of the survey was to acquire geophysical and biophysical data on seabed environments over a previously identified potential CO2 injection site to better understand the overlying seabed habitats and to assess potential for fluid migration to the seabed. Mapping and sampling was undertaken across six areas using multibeam and single beam echosounders, sub-bottom profilers, sidescan sonar, underwater towed-video, gas sensors, water column profiler, grab samplers, and vibrocorer. Over 1070 km2 of seabed and water column was mapped using the multibeam and single beam echosounder, in water depths ranging between 40 and 120 m. The sub-surface was investigated using the multichannel and the parametric sub-bottom profilers along lines totalling 730 km and 1547 km in length respectively. Specific seabed features were investigated over 44 line km using the sidescan sonar and physically and sampled at 58 stations. Integration of this newly acquired data with existing seismic data will provide new insights into the geology of the Leveque Shelf. This work will contribute to the Australian Government's National CO2 Infrastructure Plan (NCIP) by providing key seabed environmental and geological data to better inform the assessment of the CO2 storage potential in this area of the Browse Basin. This dataset contains identifications of Polychaetes collected from 64 Smith-McIntyre grabs deployed during GA0340/SOL5754.

This report provides an analysis and evaluation of fluid seepage and habitats in two targeted areas of the Petrel Sub-basin, Bonaparte Basin, northern Australia, and provides scientific information on the seabed and shallow sub-surface geology as part of a study on the potential of this area for CO2 sequestration. The Petrel Sub-basin, located beneath the modern Joseph Bonaparte Gulf, has been assessed by Geoscience Australia as part of the Australian Government funded National Low Emissions Coal Initiative (NLECI) to accelerate the development and deployment of low emissions coal technologies including geological sequestration of CO2. This study is the first undertaken by Geoscience Australia that integrates seafloor and shallow sub-surface geology data to provide information on the potential to sequester CO2 in sub-surface geological reservoirs and their suitability for purpose. In particular, this work involved the integration of data from seabed habitat characterisation studies and sub-surface geological studies to determine if evidence for fluid seepage from depth to the seabed exists at the two study sites within the Petrel Sub-basin. No evidence for hydrocarbons from depth were found. However, fluid seepage at the seabed has been and potentially is occurring; this result stemming from observations on seabe geomorphology, sedimentology, chemistry, and acoustic sub-bottom profiles.

Permeable, sandy sediments cover most of the continental shelf. The important role of pore-water advective flow on biogeochemical processes in these sediments has been highlighted in recent studies. Such flow can be driven by wave-action, water-density and interactions between topography and bottom currents, in addition to biological activity, and can create spatially complex and highly dynamic benthic environments in which processes vary on timescales ranging from minutes to months. It is well known that the patchiness of soft sediment (organic matter/bacteria, particle diversity, redox) is likely to be a major determinant of species diversity, but previous studies have not specifically defined patches based on a range of biologically-relevant physico-chemical variables, nor observed how patches change across time. This study, as part of the Surrogates Program in the Commonwealth Environmental Research Facilities Marine Biodiversity Hub, investigated temporal changes in the geochemistry, physical sediments and infauna of sandy sediments in Jervis Bay at two times.

In order to protect the diversity of marine life in Australia's Exclusive Economic Zone (EEZ), the federal parliament has passed the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. The Act is being implemented through the design of a national representative system of marine protected areas (MPAs) that will place under protection a representative portion of Australia's EEZ by 2012. A total of 13 MPAs have already been nominated for the southeast region in 2006. Limited biological data in Australia's EEZ has resulted in biophysical information compiled by Geoscience Australia being used as a proxy for seabed biodiversity in support of marine conservation planning. Information we use to characterise the seabed includes bathymetry, geomorphology, acoustic properties, sediment properties, slope and sediment mobilisation due to waves and tides. To better characterise habitats on the Australian continental shelf, Geoscience Australia is creating 'seascape' maps (similar to geological facies maps) that integrate these multiple layers of spatial data, and are useful for the prediction of the distribution of biodiversity in Australia's EEZ. This information provides 100% spatial coverage based on objective, multivariate statistical methods and offers certainty for managers and stakeholders including the oil and gas industry, who are involved with designing Australia's national MPA system. Certainty for industries operating in the EEZ is enhanced by a reproducible, science-based approach for identifying conservation priorities and the classification of seafloor types within multiple use areas.

Macrotidal coastal environments are characterised by complex patterns of sediment transport that have been poorly documented in the international literature. Of particular environmental concern is the transport of sediment from tropical coastal catchments, through estuaries and into coral reef environments. Consequently, knowledge of the distribution of benthic environments, and transport pathways of both fine and coarse sediment is required for the effective management of this issue. The Great Barrier Reef (GBR) is located on the continental shelf adjacent to the coast of tropical northeastern Australia. The GBR comprises an outer coral-dominated environment that encloses a large lagoon dominated by catchment-derived sediments. Keppel Bay is a macrotidal environment that represents the interface of the large catchment of the Fitzroy River with the southern GBR lagoon. We classified the benthic sediments of Keppel Bay into five distinct facies based on the statistical analysis of physical and geochemical sediment data and modelled seabed shear stress (the influence of waves and tidal currents). Multibeam sonar was employed to determine bedload sediment transport directions as indicated by bedform geometry, and to identify areas of sediment accumulation and erosion. Our findings suggest that much of the catchment-derived fine sediment accumulates in the mouth of the Fitzroy River. Outer Keppel Bay is dominated by relict palaeochannels, and the shoreward transport of sediment from the continental shelf. The Fitzroy River-Keppel Bay system provides a useful facies model for a seasonal, sediment-starved macrotidal depositional setting in which bedrock configuration and relict features dominate geomorphology, and restrict processes of modern sediment accumulation.

The Petrel Sub-basin Marine Survey GA-0335 (SOL5463) was acquired by the RV Solander during May 2012 as part of the Commonwealth Government's National Low Emission Coal Initiative (NLECI). The survey was undertaken as a collaboration between the Australian Institute of Marine Science (AIMS) and GA. The purpose was to acquire geophysical and biophysical data on shallow (less then 100m water depth) seabed environments within two targeted areas in the Petrel Sub-basin to support investigation for CO2 storage potential in these areas. Underwater video footage and still photographic images (12 megapixel resolution) from towed-video were acquired from 11 stations. The quality of imagery varies among transects and some still images were not of suitable quality for analysis. No still images are available for stations 2, 4 and 7 due to system malfunction. Video and still image files and associated parent folders are named by station number, gear code (CAM = underwater camera system) and then the deployment number. For example 'STN08CAM06' would represent a video transect from Station 08 that was the 6th video transect of the survey. Please note that the Ultra-short Baseline (USBL) acoustic tracking system used to track the towed-camera system failed early in the survey; hence geo-location of video transects and stills could only be linked to the R.V. Solander's ship navigation.

Three areas in the Torres Strait-Gulf of Papua region were selected for detailed study of sediments and benthic fossil biota. These areas form a transect across the shelf from the Fly River Delta to the shelf edge, near the northern extremity of the Great Barrier Reef. The Torres Strait-Gulf of Papua shelf is a shallow, low-gradient platform, where the shelf edge occurs between 120 and 140 m depth. In the study area, where the sediments range from muddy to gravelly carbonate sands, the sediment deposition rates are low and the relict content of sediment is often high. The three areas show distinct differences in benthic foraminiferal assemblages as indicated by relative abundances at the order level, as well as distribution patterns of individual species; these differences are also reflected in the total microbiotic communities. Given the high relict content in the surface material across these sites, a foraminiferal preservation scale was developed to assess the extent of reworking. Taphonomic features indicate that abrasion is the main factor affecting preservation. Despite poor preservation of the foraminiferal tests, the benthic foraminiferal species have a strong correlation to water depth, indicating that transportation pathways are short. Application of multivariate statistics to analyze the relationship between environmental attributes and the distributions of the microbiota and foraminiferal species indicates the additional importance of factors including percent carbonate mud, percent gravel, organic carbon flux, temperature, salinity and mean grain size. The benthic foraminifera produce a much stronger correlation to the environmental variables than the microbiota, indicating that these organisms can provide a detailed assessment of habitat types.

The Vlaming Basin survey (GA survey # 334) was conducted under the Nation CO2 Infrastructure Plan (NCIP) on the MV Southern Supporter between the 12th to the 21st April 2012, with technical support provided from Fugro. The survey obtained geological (sedimentological, geochemical, geophysical) and biological data to support assessments of offshore acerage release areas for potential CO2 storage, and investigate the relationships between the physical environment and associated biota for biodiversity prediction. The purpose of the survey was to contribute to the assessment of the Vlaming Sub-basin for containment risk, as well as complement and validate interpretation of seismic data in the same area. Underwater footage was collected from 12 stations, although quality varies between sites and among transect lines. Video folders are named according to station number, followed by gear code (CAM=Ray Tech Underwater system), then the deployment number, and followed by region. For example, 12CAM02_D1 represents a video transect from station 12 that was the 2nd video transect of the survey and located in area region D1. Multiple files within transect folders indicate location metadata (Start of line location). In addition, USBL (Ultra-short baseline) text files located in the same folder provide continuous navigational information on location, time (UTC) and depth of each video transect line.