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The Magnitude and Frequency of Combined Flow Bed Shear Stress as a Measure of Exposure on the Australian Continental Shelf

Created 16/10/2025

Updated 16/10/2025

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Benthic habitats on the continental shelf are strongly influenced by exposure to the effects of surface ocean waves, and tidal, wind and density driven ocean currents. These processes combine to induce a combined flow bed shear stress upon the seabed which can mobilise sediments or directly influence organisms disturbing the benthic environment. Output from a suite of numerical models predicting these oceanic processes have been utilised to compute the combined flow bed shear stresses over the entire Australian continental shelf for an 8-year period (March 1997- February 2005 inclusive). To quantify the relative influence of extreme or catastrophic combined flow bed shear stress events and more frequent events of smaller magnitude, three methods of classifying the oceanographic levels of exposure are presented:

A spectral regionalisation method, A method based on the shape of the probability distribution function, and A method which assesses the balance between the amount of work a stress does on the seabed, and the frequency with which it occurs.

Significant relationships occur between the three regionalisation maps indicating seabed exposure to oceanographic processes and physical sediment properties (mean grain size and bulk carbonate content), and water depth, particularly when distinction is made between regions dominated by high-frequency (diurnal or semi-diurnal) events and low-frequency (synoptic or annual) events. It is concluded that both magnitude and frequency of combined-flow bed shear stresses must be considered when characterising the benthic environment. The regionalisation outputs of the Australian continental shelf presented in this study are expected to be of benefit to quantifying exposure of seabed habitats on the continental shelf to oceanographic processes in future habitat classification schemes for marine planning and policy procedures.

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Field Value
Title The Magnitude and Frequency of Combined Flow Bed Shear Stress as a Measure of Exposure on the Australian Continental Shelf
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/2e9f9c4b-e46b-4edf-9c7f-85652ef0eea2
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 22/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        96.0,
        -44.0
      ],
      [
        160.0,
        -44.0
      ],
      [
        160.0,
        -9.0
      ],
      [
        96.0,
        -9.0
      ],
      [
        96.0,
        -44.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The Magnitude and Frequency of Combined Flow Bed Shear Stress as a Measure of Exposure on the Australian Continental Shelf". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-magnitude-and-frequency-of-combined-flow-bed-shear-stress-as-a-measure-of-exposure-on-the-a