Photography and Video
Unlike land based environments, relatively little is known about what the seafloor around Australia looks like or has living on it. Geoscience Australia undertakes a range of marine surveys to improve the understanding and the management of Australia's marine environments. One component of the research is to use a towed video system to directly observe coastal and deep sea environments. This aids in the identification of habitats and the organisms that live in them. In some regions these surveys build on existing knowledge, but in many areas, particularly in deep offshore sites, these devices provide the first images of the seafloor.
A towed video system is composed of a metal frame which has an underwater video camera with lights and specialised sensors. Using a winch on the ship, the video system is lowered to 1-2 metres above the seafloor and is then towed along at 1-2 knots. This speed and altitude allows the video camera to record sharp images of the seafloor while covering a relatively long distance. These images are sent directly up the cable to a TV screen on the ship so that the images are seen in real time. The hours of video footage collected of the seafloor provides a wealth of information about the types of geological features, habitats and life forms which occur in the different parts of Australia's marine jurisdiction.
Scientists at Geoscience Australia have developed a method which allows them to rapidly collect geological and biological information in real-time using the video footage of the seafloor (Anderson et al 2008). This means data contained on the video can be collected and processed while at sea within hours of the video data being collected, including production of maps. This reduces dramatically the timeframe in which seafloor information can be made available for research and management applications. Video data can be overlain on acoustic data such as multibeam bathymetry and backscatter to examine the relationships between seafloor depth and shape, composition and plant and animal distributions. Directly observing the seafloor geology and plants and animals not only allows for rapid characterisation but it also provides the foundation to monitor future changes.
Topic contact: firstname.lastname@example.org Last updated: November 22, 2010