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| David Steinberg
Northern Territory Department of Primary Production [details]
|The search for the Macumba will be based on a grid search area defined by the interpretation of historic marks and discounting areas previously searched. The size of the search area and the methodology used will, in part, be informed by the tools available and also the amount of time committed to the task. It is hoped that 6-12 hours searching and recording can be committed to the task although if successful early, less overall time will be required. If the voyage can only commit to passing through the search area once, or a far limited number of times, this is still a worthwhile exercise. In a multi beam or side scan sonar survey the lanes will be defined by the sonar coverage, taking into account the need for overlap to accommodate the gap beneath the sonar fish itself. As the sea bed terrain in the general area is flat it’s surmised that there will be little topography to create shadows and complicate interpreting the signal. We appreciate that multi beam is provided and the Heritage Branch can supply a side scan sonar if need be. Other than the side scan and multi-beam another commonly used tool is a magnetometer. Magnetometers are particularly good in search for the search of iron and steel wrecks. A search pattern within the search area using a magnetometer will be similar, with a fish towed following predetermined lanes. The magnetometer signal will be significant as this is a 2,500 ton steel ship in a relatively shallow seabed, although the device will need to be adjusted to accommodate the high ambient noise of the areas ferrous geology. A basic calculation taking into account the magnetometer, the size of the vessel and the depth of the water will determine the search lanes. Once the wreck is located the multi beam and/or side scan sonar will be used to take multiple impressions of the wreck. Adjusting the run of the ship will provide multiple perspectives of this complex archaeological site. ROV cameras are not listed on the ship equipment list, but other partners may be sourced to provide this. Remote video has been used on marine life surveys of wrecks in the Northern Territory previously. The ship’s bottom profilers will be used to determine heights of the seabed and wreckage to provide a profile of the wreck and guide future dive operations. Once the wreck is located and a series of side scan runs over the wreck completed any further research on the marine survey of the wreck can be supported. Biological surveys may focus on the biodiversity of surface life, water column and wreck dwelling species. Side scan sonar can capture the scale and location of a ‘bait ball’ for example. ROV can be used to record wreck dwelling species and benthic life. Remote wreck surveys provide unique challenges for both maritime archaeologists and marine biologists, and the Macumba project will provide an opportunity to develop synergies and shape strategies to record these complex sites.
List of surveys that this project was on.
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|Andrew Bowie (UTAS)
|The application will support research to quantify the importance of iron-rich aerosols from Australia for marine biogeochemistry and ocean ecosystem health. The project will sample and conduct experiments on atmospheric particles containing terrestrial dust and bushfire smoke that are transported from Australia to its surrounding oceans. The application supports the training and research of two postgraduate students from IMAS-UTAS. The outcomes will provide a scientific basis for managing the complex role of iron in sustaining marine ecosystem biodiversity and for informing government policy on ocean fertilisation as a carbon mitigation strategy.