This report contains the preliminary results of Geoscience Australia survey 273 to northwest Torres Strait. This survey was undertaken as part of a research program within the Torres Strait CRC aimed at understanding marine biophysical processes in Torres Strait and their effect on seagrass habitats. Two Geoscience Australia surveys were undertaken as part of this program, survey 266 measured monsoon season conditions (Heap et al., 2005), and survey 273 measured trade wind conditions. Section 6 compares and contrasts the survey results acquired for both surveys. Section 7 addresses the results of the survey program in light of the objectives of the CRC proposal. Survey 273 acquired numerous different data types to assist with characterising the mobile sediments and hydrodynamic nature of the region. Multibeam sonar, current meters, grab samples, vibro-cores, underwater video, meteorological data (from the Bureau of Meteorology), Landsat imagery, were all used to characterise the seabed hydrodynamics of Torres Strait.

The National Geochemical Survey of Australia (NGSA) project (www.ga.gov.au/ngsa) was part of Geoscience Australia's Onshore Energy Security Program 2006-2011 and was carried out in collaboration with the geological surveys of all States and the Northern Territory. It delivered (1) Australia's first national geochemical atlas, (2) an underpinning geochemical database, and (3) a series of reports. Catchment outlet sediments (similar to floodplain sediments in most cases) were sampled in 1186 catchments covering ~80% of the country (average sample density 1 sample per 5500 km2). Samples were collected at 2 depths each sieved to 2 grain size fractions. Chemical analyses carried out on the samples fall into 3 main categories: (1) total (using mainly XRF and total digestion ICP-MS), (2) aqua regia, and (3) Mobile Metal Ion® (MMI) element contents. The MMI analyses were conducted on the surface (0-10 cm) samples sieved to <2 mm, in one single batch, by ICP-MS. Concentrations of 54 elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Hg, K, La, Li, Mg, Mn, Mo, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, U, V, W, Y, Yb, Zn and Zr) were determined. Maps and quality assessment of these data are presented in reports available from the project website. Preliminary interpretations of the MMI dataset suggest that it potentially has significant value in geological, mineral exploration and agronomic (e.g., bioavailability) applications.

This dataset contains species identifications of molluscs collected during survey SOL5117 (R.V. Solander, 30 July - 27 August, 2010). Animals were collected from the Joseph Bonaparte Gulf with a benthic sled (SL) and Smith McIntyre grab (GR). Specimens were lodged at Northern Territory Museum on the 27 August 2010. Species-level identifications were undertaken by Richard Willan at the Northern Territory Museum and were delivered to Geoscience Australia on the December 2010 (for large samples) and 26 June 2012 (for smaller molluscs from grabs). See GA Record 2011/08 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. Comments: The following comments relate to live-taken specimens only: 1. The SOL5117 molluscan samples contain at least one new species (Talabrica sp.), one new record for Australia (Oliva rufofulgurata), and five new records for Commonwealth waters north of the Northern Territory (Strombus hickeyi, Trigonostoma textilis, Dentalium formosum, Phyllidiopsis shireeenae, Ceratosoma trilobatum). 2. Many of the molluscan species in the SOL5117 grab samples, both live individuals and dead shells, are represented only by tiny juveniles, so identification to species level is not possible because the shell characters change considerably as the species reaches maturity. 3. Clearly the majority of molluscs in the SOL5117 samples are represented by dead shells only. 4. Species richness is far higher than suggested by these samples. Judging from the range of species present in the SOL4934 and SOL5117 samples plus the accumulation of species through the samples, the molluscan biodiversity in this area would be between 400 and 500 species, the great majority micromolluscs (i.e., < 5 mm in greatest dimension). 5. The SOL5117 molluscan samples are not as comprehensive as the earlier SOL4934 samples taken in the same areas(s). 6. The SOL5117 molluscan samples provide us with hardly any picture of the composition or abundance of molluscs within or between the sites. 7. The SOL5117 molluscan samples should not be used to assess the conservation status of the submarine communities in the area(s) sampled. 8. More targeted and intensive sampling is required to appropriately measure molluscan diversity, abundance and communities in this region. ~ R Willan

Geoscience Australia is supporting the exploration and development of offshore oil and gas resources and establishment of Australia's national representative system of marine protected areas through provision of spatial information about the physical and biological character of the seabed. Central to this approach is prediction of Australia's seabed biodiversity from spatially continuous data of physical seabed properties. However, information for these properties is usually collected at sparsely-distributed discrete locations, particularly in the deep ocean. Thus, methods for generating spatially continuous information from point samples become essential tools. Such methods are, however, often data- or even variable- specific and it is difficult to select an appropriate method for any given dataset. Improving the accuracy of these physical data for biodiversity prediction, by searching for the most robust spatial interpolation methods to predict physical seabed properties, is essential to better inform resource management practises. In this regard, we conducted a simulation experiment to compare the performance of statistical and mathematical methods for spatial interpolation using samples of seabed mud content across the Australian margin. Five factors that affect the accuracy of spatial interpolation were considered: 1) region; 2) statistical method; 3) sample density; 4) searching neighbourhood; and 5) sample stratification by geomorphic provinces. Bathymetry, distance-to-coast and slope were used as secondary variables. In this study, we only report the results of the comparison of 14 methods (37 sub-methods) using samples of seabed mud content with five levels of sample density across the southwest Australian margin. The results of the simulation experiment can be applied to spatial data modelling of various physical parameters in different disciplines and have application to a variety of resource management applications for Australia's marine region.

A number of terms used in this book are derived from the fields of biogeography and benthic ecology and these are defined in the glossary; the reader is also referred to the works cited at the end of this chapter for further information. Many of the case studies presented in this book refer to habitat classification schemes that have been developed based on principles of biogeography and ecology. For these reasons a brief overview is provided here to explain the concepts of biodiversity, biogeography and benthic ecology that are most relevant to habitat mapping and classification. Of particular relevance is that these concepts underpin classification schemes employed by GeoHab scientists in mapping habitats and other bioregions. A selection of published schemes, from both deep and shallow water environments, are reviewed and their similarities and differences are examined.

Climate change is threatening tropical reefs across the world, with most scientists agreeing that the current changes in climate conditions are occurring at a much faster rate than in the past and are potentially beyond the capacity of reefs to adapt and recover. Current research in tropical ecosystems focuses largely on corals and fishes, although other benthic marine invertebrates provide crucial services to reef systems, with roles in nutrient cycling, water quality regulation, and herbivory. We review available information on the effects of environmental conditions associated with climate change on noncoral tropical benthic invertebrates, including inferences from modern and fossil records. Increasing sea surface temperatures may decrease survivorship and increase the developmental rate, as well as alter the timing of gonad development, spawning, and food availability. Environmental changes associated with climate change are linked to larger ecological processes, including changes in larval dispersal and recruitment success, shifts in community structure and range extensions, and the establishment and spread of invasive species. Loss of some species will trigger economic losses and negative effects on ecosystem function. Our review is intended to create a framework with which to predict the vulnerability of benthic invertebrates to the stressors associated with climate change, as well as their adaptive capacity. We anticipate that this review will assist scientists, managers, and policy-makers to better develop and implement regional research and management strategies, based on observed and predicted changes in environmental conditions.

This introductory chapter provides an overview of the book's contents and definitions of key concepts including benthic habitat, potential habitat and seafloor geomorphology. The chapter concludes with a summary of commonly used habitat mapping technologies. Benthic (seafloor) habitats are physically distinct areas of seabed that are associated with particular species, communities or assemblages that consistently occur together. Benthic habitat maps are spatial representations of physically distinct areas of seabed that are associated with particular groups of plants and animals. Habitat maps can illustrate the nature, distribution and extent of distinct physical environments present and importantly they can predict the distribution of the associated species and communities.

This professional opinion assesses the viability of utilising the priority aquifer target GWMAR1 to secure Broken Hill's water supply, both as an extractive only scheme and as a conjunctive use scheme employing Managed Aquifer Recharge as a key component. This work comes under the arrangements of the Broken Hill Managed Aquifer Recharge Project Phase 3a Memorandum of Understanding. The report addresses, with confidence levels, the following issues: Option 1: Groundwater Extraction Only. This includes an estimation of the water storage capacity and ambient groundwater salinity of the GWMAR1 priority target and the Jimargil sub-area. Different confidence levels are attached to these two estimates, reflecting the focus of work to date on the Jimargil sub-area. Broader groundwater quality issues will also be discussed. An assessment is also made of the issues with respect to direct groundwater extraction as the sole option for securing Broken Hill's water supply for a minimum of 3 years (approximately 30GL). Option 2 assesses the use of the GWMAR1 priority aquifer as part of a conjunctive water supply incorporating Managed Aquifer Recharge. This includes an assessment of the suitability of the priority MAR target at Jimargil based on the National MAR Risk Assessment Guidelines. The report also includes specification of the remaining information gaps and potential risks to a project to utilise the aquifer for (1) Groundwater extraction and (2) a conjunctive supply utilising Managed Aquifer Recharge. Broken Hill and Menindee. The report also includes a short summary of communities in Australia that currently rely on Managed Aquifer Recharge to supply their potable water, and management issues associated with this supply, and future considerations to a possible implementation phase of providing water security to Broken Hill and Menindee from a regional aquifer.

This record is a review and synthesis of geological research undertaken along the northern margin of Australia. The record has been written in support of regional marine planning and provides fundamental baseline scientific information for the Northern Planning Area.

Physical sedimentological processes such as the mobilisation and transport of shelf sediments during extreme storm events give rise to disturbances that characterise many shelf ecosystems. The intermediate disturbance hypothesis predicts that biodiversity is controlled by the frequency of disturbance events, their spatial extent and the amount of time required for ecological succession. A review of available literature suggests that periods of ecological succession in shelf environments range from 1 to over 10 years. Physical sedimentological processes operating on continental shelves having this same return frequency include synoptic storms, eddies shed from intruding ocean currents and extreme storm events (cyclones, typhoons and hurricanes). Modelling studies that characterise the Australian continental shelf in terms of bed stress due to tides, waves and ocean currents were used here to create a map of ecological disturbance, defined as occurring when the Shield's parameter exceeds a threshold of 0.25. We also define a dimensionless ecological disturbance ratio (ED) as the rate of ecological succession divided by the recurrence interval of disturbance events. The results illustrate that on the outer part of Australia's southern, wave-dominated shelf the mean number of days between threshold events that the Shield's parameter exceeds 0.25 is several hundred days.