In this study of the beach-ridge plain at Keppel Bay, on the central coast of Queensland, we examine ridge morphology, sediment texture and geochemistry. We build a detailed chronology for the ridge succession using the optically stimulated luminescence (OSL) dating method. Although our interpretations are preliminary, our results suggest that significant changes have occurred in the rate of shoreline accumulation of sediment, catchment sediment source areas, and that there have been minor falls in relative sea level.

The Fitzroy River delivers large amounts of nutrients and fine sediments to Keppel Bay (contiguous with the Great Barrier Reef Lagoon) during intermittent flow events. This study explores sources, forms and transformations of nutrients in Keppel Bay, and develops a functional process zonation that integrates seabed geochemistry and water column nutrient characteristics which are controlled by suspended sediment. The water column and seabed properties were investigated over two dry seasons, with supplementary core incubations taken to measure carbon decomposition rates and nutrient fluxes. Keppel Bay can be divided into three zones, the: zone of maximum resuspension (ZMR); coastal transitional zone (CTZ); and blue water zone (BWZ). Mineralisation of predominantly terrestrial organic matter occurs in the ZMR where nutrient uptake by phytoplankton is light limited. The CTZ and BWZ had higher light penetration and phytoplankton growth was likely limited by N and P, respectively. The identified zones conform to the bathymetry and hydrodynamic characteristics of the bay, allowing for the development of an integrated conceptual model accounting for the benthic and pelagic biogeochemical processes. Recognition of these different zones shows that considerable variation in benthic and water column properties is possible within a small system with the bathymetric and hydrodynamic characteristics of the fluidised bed reactor.

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....

Beach ridges at Keppel Bay, central Queensland, Australia, preserve a record of sediment accumulation from the historical period back to middle Holocene times. The ridges comprise fine, well-sorted, feldspar-rich quartz sand that was eroded from the Fitzroy River catchment, deposited in Keppel Bay during floods of the Fitzroy River, and reworked onshore into beach and foredune deposits by the prevailing currents, waves and wind. These floods have an average recurrence interval of at least 7 yr and are induced by the passage of cyclones onshore into the large Fitzroy catchment. The youngest series of beach ridges sit sub-parallel to the modern beach and comprise six accretional units, each unit formed by a set of ridges and delineated by prominent swales. Optically stimulated luminescence (OSL) ages of beach ridges in these units indicate they were deposited in periods of rapid progradation approximately 1500, 1000, 450 and 230 yr BP, when there was an enhanced supply of sediment to the beach from the Fitzroy River via Keppel Bay. Estimates of the mass of sediment stored in the beach-ridge strandplain show that it represents a significant sediment store, potentially trapping the equivalent of 79% of the estimated long-term (100 yr) average annual bedload of the Fitzroy River that is deposited in Keppel Bay. There has been a reduction in the rate of sediment accumulation in the strandplain since around 1000 yr BP, which is consistent with other coastal records in eastern Australia of a relatively wetter phase of climate in the late Holocene compared to the present. The youngest beach ridges (OSL ages < 100 yr BP) are tall relict foredunes that reflect a low rate of sediment accumulation. These ridges have a distinctive trace-element composition produced by a greater contribution from catchment areas with basaltic soils. The change in catchment provenance has likely been a consequence of erosion that followed clearing of native vegetation in these areas. Our findings demonstrate the important insights that beach-ridge deposits proximal to a river sediment source can provide into processes of sediment accumulation and the response to variations in climate in tropical coastal sedimentary systems.

This map shows the area of the Kuuku Ya'u Native Title Claim, which extends approximately between Olive River and Nyllichi Point in Cape York Peninsula, Queensland. The map was produced for the Attorney-General's Department. Not for public distribution.

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 shapefiles 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 dataset is published with the permission of the CEO, Geoscience Australia.

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.

No abstract available