Diatom assemblages in sandy deposits of the 2004 tsunami at Phra Thong Island, Thailand may provide clues to flow conditions during the tsunami. The tsunami deposits contain one or more beds that fine upward, commonly from medium sand to silty very fine sand. Diatom assemblages of the lowermost portion of the deposit predominantly comprise of unbroken beach and subtidal species that live attached to sand grains. The dominant taxa shift to marine plankton species in the middle of the bed and to a mix of freshwater, brackish, and marine species near the top. These trends are consistent with expected changes in current velocities of tsunami through time. During high current velocities, medium sand is deposited; only beach and subtidal benthic diatoms attached to sediment can be incorporated into the tsunami deposit. High shear velocity keeps finer material, including planktonic diatoms in suspension. With decreasing current velocities, finer material including marine plankton can be deposited. Finally, during the lull between tsunami waves, the entrained freshwater, brackish, and marine species settle out with mud and plant trash. Low numbers of broken diatoms in the lower medium sand implies rapid entrainment and deposition, whilst selective breakage of marine plankton (Thalassionema nitzschioides, and Thalassiosira and Coscinodiscus spp.) in the middle portion of the deposit probably results from abrasion in the turbulent current before deposition.

This dataset maps the geomorphic habitat environments (facies) for 36 South Australian coastal waterways. The classification system contains 12 easily identifiable and representative environments: Barrier/back-barrier, Bedrock, Central Basin, Channel, Coral, Flood- and Ebb-tide Delta, Fluvial (bay-head) Delta, Intertidal Flats, Mangrove, Rocky Reef, Saltmarsh/Saltflat, Tidal Sand Banks (and Unassigned). These types represent habitats found across all coastal systems in Australia. Most of the 36 coastal waterways have a "Modified" environmental condition (as opposed to "Near Pristine"), according to the National Land and Water Resources Audit definition.

This Milestone Report documents the results of the analysis of sediment samples collected during the survey of Sydney Harbour in August, 2003. The samples were collected by Geoscience Australia (GA) and Defence Science and Technology Organisation (DSTO). The sediment sampling programme was undertaken as part of the coastal geomorphology and classification sub-project of the Coastal CRC - Coastal Water Habitat Mapping Project. Samples were collected to assess the physical character of the sediments and map their distribution for comparison with the geomorphology of the estuary floor using new and existing swath bathymetry data. The analysis of the sediment samples will be used to groundtruth the areas surveyed with the Coastal CRC's Reson SeaBat 8125 multibeam sonar mapping system. Approximately one third of the targeted area was covered by the Seabat 8125 in the first survey, due to problems with the survey boat. The remaining area will be surveyed in the second Sydney Harbour survey, which is planned for September/October 2004. The sediment data will be used to assess how the physical properties of the benthos vary spatially and how they influence acoustic backscatter waveforms to classify benthic habitats. The study builds upon the existing knowledge of the geomorphology of the seabed in Sydney Harbour. The report also discusses issues of interpretation and equipment selection for the toolkit as well as other completed work.

Objectives 1. To determine the horizontal and vertical extent of hydrogen sulphide (H2S) in Lake Wollumboola sediments. 2. To examine controls on H2S gas production in Lake Wollumboola sediments. Activities 1. During a visit to Lake Wollumboola in November 2001, Geoscience Australia collected sediment samples, from sediment cores to depths of generally 180 mm, and occasionally to 600 mm. 2. The 12 sample sites chosen incorporate the three different sediment types of Lake Wollumboola; marine sands on the eastern side of the lake, central basin muds in the relatively deeper central part of the lake, and fluvial sands and muds on the western side of the lake where the creeks are depositing sediment from the catchment. 3. We measured H2S in sediment porewaters, immediately after sample collection. Porewater sulphate and chloride were measured in the laboratory. 4. Total sulphur, total iron, and total organic carbon were measured in the laboratories at Geoscience Australia, after the survey. Background Bacteria, which occur naturally in Lake Wollumboola's sediments, produce H2S when they breakdown organic matter. The bacteria, which are called sulphate reducing bacteria, utilise sulfate from the water to breakdown the organic matter, and can only operate under oxygen free (anoxic) conditions. Key Findings 1. H2S production in Lake Wollumboola is extensive. The average H2S concentration in the central basin muds and fluvial sands and muds is ~3000 M. At one site in the central basin muds, H2S concentration is greater than 10 000 M. In contrast, the concentration of H2S in the sandy marine sediments on the eastern side of the lake is low in comparison to the central basin muds and fluvial delta sands and muds. The average H2S concentration in the marine sands is 158 M. 2 Measurements of total organic carbon show that the amount of organic matter is higher in the central basin muds and fluvial delta sands and muds (~3.5 wt%) than in the marine sands (~0.8 wt%). Organic matter is the fuel for H2S production. High H2S concentrations in the central basin muds and fluvial delta sands and muds are probably a result of their high organic matter contents. 3. Depth profiles of H2S concentration and sulphate depletion in the central basin muds and fluvial sands and muds show that H2S production is occurring right at the sediment surface and down to depths of 80-100 mm. This implies that H2S could escape directly into the atmosphere, when the central basin muds and fluvial sands and muds are exposed during times of low lake levels. It also suggests that H2S could build up in the bottom layer of water directly above these sediments if the water remains anoxic for periods of time. 4. Total sulphide measurements show that H2S is reacting with iron in the sediments, forming iron sulphide minerals. Iron is an important trapping mechanism for H2S, preventing its escape to the atmosphere. Most sites, however, do not have enough `reactive iron' available and H2S concentrations are able to build-up in the porewaters of the sediment.

This record contains the raw Ground Penetrating Radar (GPR) data and scanned field notes collected on fieldwork at Old Bar and Boomerang Beaches, NSW for the Bushfire and Natural Hazards CRC Project, Resilience to Clustered Disaster Events on the Coast - Storm Surge. The data was collected from 3 - 5 March 2015 using a MALA ProEx GPR system with 250 MHz shielded and 100 MHz unshielded antennaes. The aim of the field work was to identify and define a minimum thickness for the beach and dune systems, and where possible depth to any identifiable competent substrate (e.g. bedrock) or pre-Holocene surface which may influence the erosion potential of incident wave energy. Surface elevation data was co-acquired and used to topographically correct the GPR profiles.

This record contains the processed Ground Penetrating Radar (GPR) data (.segy), field notes, and shapefile collected on fieldwork at Adelaide Metropolitan Beaches, South Australia for the Bushfire and Natural Hazards CRC Project, Resilience to Clustered Disaster Events on the Coast - Storm Surge. The data was collected from 16-19 February 2015 using a MALA ProEx GPR system with 250 MHz shielded, 100 MHz unshielded and 50 MHz unshielded antennaes. The aim of the field work was to identify and define a minimum thickness for the beach and dune systems, and where possible depth to any identifiable competent substrate (e.g. bedrock) or pre-Holocene surface which may influence the erosion potential of incident wave energy. Surface elevation data was co-acquired and used to topographically correct the GPR profiles. This dataset is published with the permission of the CEO, Geoscience Australia.

As part of the National Coastal Vulnerability Assessment currently being undertaken by the Commonwealth Department of Climate Change, Geoscience Australia is developing a nationally consistent geomorphic classification of the Australian coastal zone. Mapped coastal geomorphology is a fundamental data layer required by all levels of government to undertake modelling of coastal processes and assessment of coastal vulnerability to the potential impacts of global climate change. A digital coastal geomorphology map, combined with a high resolution digital elevation model, will allow for detailed sea-level rise modelling and assist in the identification of potentially susceptible landform units.

Geoscience Australia is the national custodian for coastal geoscientific data and information. The organisation developed the OzCoasts web-based database and information system to draw together a diverse range of data and information on Australia's coasts and its estuaries. Previously known as OzEstuaries, the website was designed with input from over 100 scientists and resource managers from more than 50 organisations including government, universities and the National Estuaries Network. The former Coastal CRC and National Land and Water Resources Audit were instrumental in coordinating communication between the different agencies. Each month approximately 20,000 unique visitors from more than 140 countries visit the website to view around 80,000 pages. Maps, images, reports and data can be downloaded to assist with coastal science, monitoring and management. The content is arranged into six inter-linked modules: Search Data, Conceptual Models, Coastal Indicators, Habitat Mapping, Natural Resource Management, Landform and Stability Maps. More....

Eutrophication has become a growing concern for lakes, estuaries and other coastal waters in southwestern Western Australia since about 1945 when the application of phosphatic fertilisers was increased to compensate for nutrient deficient soils (Hodgkin and Hamilton, 1993). This study reports on a number of bulk sediment parameters (e.g. TOC, TN, TP & TS, d13C, and TOC/TN, TOC/TP C/S and Mg:Fe ratios) that have been measured for a suite of estuaries from southwestern WA. The data are interpreted in terms of sources of organic matter to-, and climatic, geomorphic, anthropogenic and biotic controls on sediment concentrations of C, P and N at southwestern Australian sites. The bulk sediment characteristics of the WA estuaries are also compared to those from a large number of coastal waterways from around Australia.

No abstract available