Harris, P. T., Bridge, T. C. L., Beaman, R. J., Webster, J. M., Nichol, S. L., and Brooke, B. P. 2013. Submerged banks in the Great Barrier Reef, Australia, greatly increase available coral reef habitat. – ICES Journal of Marine Science, 70: 284–293. Anthropogenic global ocean warming is predicted to cause bleaching of many near-sea-surface (NSS) coral reefs, placing increased importance on deeper reef habitats to maintain coral reef biodiversity and ecosystem function. However, the location and spatial extent of many deep reef habitats is poorly known. The question arises: how common are deep reef habitats in comparison with NSS reefs? We used a dataset from the Great Barrier Reef (GBR) to show that only about 39% of available seabed on submerged banks is capped by NSS coral reefs (16 110 km2); the other 61% of bank area (25 600 km2) is submerged at a mean depth of around 27 m and represents potential deep reef habitat that is spatially distributed along the GBR continental shelf in the same latitudinal distribution as NSS reefs. Out of 25 600 km2 of submerged bank area, predictive habitat modelling indicates that more than half (around 14 000 km2) is suitable habitat for coral communities.
1 January 2001 in Journal of the Geological Society
The Coorong Coastal Plain in southeastern South Australia preserves a long Quaternary record of cool-water, temperate-carbonate sedimentation in the form of high wave energy, barrier shoreline deposits and associated back-barrier lagoon facies that formed during successive sea-level highstands. Whole-rock samples of bioclastic skeletal carbonate sand with subordinate quartz were collected from aeolian facies (modern and relict foredunes) of a Holocene embayment fill and from ten Pleistocene barriers across the coastal plain in a transect from Robe to Naracoorte. The extent of leucine racemization (total acid hydrolysate and free amino acids) in the Pleistocene skeletal carbonate sand (63–500 μm) increases monotonically with age and is consistently higher than for entire fossil molluscs from the same allostratigraphic units, reflecting the lengthy residence time for bioclasts in this high wave energy environment, and sediment recycling from the erosion of older barriers. The extent of racemization in the whole-rock samples conforms with a model of apparent parabolic racemization kinetics and the calculated ages largely agree with previously determined luminescence ages. Apart from a possible reinterpretation of the significance of the West Naracoorte Range, the coastal plain succession indicates that interglacial sea levels did not deviate by more than 6 m of present sea level for the Mid- and Late Pleistocene thus providing an important framework for quantifying ice volume during sea-level highstands and calibrating the oxygen isotope record.
The effort and cost required to convert satellite Earth Observation (EO) data into meaningful geophysical variables has prevented the systematic analysis of all available observations. To overcome these problems, we utilise an integrated High Performance Computing and Data environment to rapidly process, restructure and analyse the Australian Landsat data archive. In this approach, the EO data are assigned to a common grid framework that spans the full geospatial and temporal extent of the observations – the EO Data Cube. This approach is pixel-based and incorporates geometric and spectral calibration and quality assurance of each Earth surface reflectance measurement. We demonstrate the utility of the approach with rapid time-series mapping of surface water across the entire Australian continent using 27 years of continuous, 25 m resolution observations. Our preliminary analysis of the Landsat archive shows how the EO Data Cube can effectively liberate high-resolution EO data from their complex sensor-specific data structures and revolutionise our ability to measure environmental change.