Autonomous Underwater Vehicles
The Autonomous Underwater Vehicles Facility provides precisely navigated time series measurements of benthic imagery using Autonomous Underwater Vehicles (AUVs) at selected locations on Australia’s continental shelf. While very large-scale surface processes can be addressed adequately by remote sensing and ship-borne systems, characterisation of many marine processes requires the ability to sense at high resolution in close proximity to the seafloor. The ability to conduct geo-referenced, high resolution, repeatable surveys of marine habitats – particularly those beyond diver depths – represents one of the key benefits of AUVs. The facility incorporates a suite of observing programs that capitalise on the unique capabilities of AUVs and provides a critical observational link between oceanographic and benthic processes. To support a more complete understanding of natural, climate change, and human-induced variability in shelf environments, the facility generates physical and biological observations of benthic variables that cannot be cost-effectively obtained by other means.
The AUV Facility is undertaking arguably the world’s first benthic observing program to make extensive use of AUVs for the purpose of monitoring benthic habitats on such a large scale. The surveys are broadly divided into temperate and tropical reef environments and span the entire latitudinal range of the Australian continent.
Instrumentation and Data
The Autonomous Underwater Vehicle facility currently owns and operates the ocean going AUV called ‘Sirius’. Managed by the University of Sydney’s Australian Centre for Field Robotics (ACFR) this vehicle is a modified version of a mid-size robotic vehicle called Seabed built at the Woods Hole Oceanographic Institution. Sirius is specifically designed for undertaking high resolution benthic optical and acoustic imaging work and is equipped with a full suite of oceanographic instruments. These include a high resolution stereo camera pair and strobes, a 330 kHz multibeam sonar, depth and conductivity/temperature sensors, a 1200 kHz Doppler Velocity Log (DVL) including a compass with integrated roll and pitch sensors, an ultra-short baseline acoustic tracking and communications system and a flurometer to measure coloured dissolved organic matter (CDOM), chlorophyll-a and backscatter. Data is time-stamped and logged on the vehicles on-board computer. Optical imagery collected by the AUV Sirius in Australian waters can be found through the AUV Image Viewer and the Australian Ocean Data Network (AODN) Portal.
Application of Data
1. Survey off Maatsuyker Island in the Tasman Fracture Commonwealth Marine Reserve
The AUV was deployed in March 2015 to examine the benefits of a no-take marine reserve off Tasmania's wild southwest coast. The research is comparing the marine life and seafloor habitat in fished environments with those found within the Tasman Fracture Commonwealth Marine Reserve (CMR) southeast of Tasmania. A section of this reserve has been no-take protected for over seven years, and evaluating the effects of such protection is an important part of managing the CMR network in Australian waters. To read more and to watch a short video to hear Dr Neville Barrett and Professor Stefan Williams explain the research and the AUV further click here.
2. Variable Responses of Benthic Communities to Anomalously Warm Sea Temperatures on a High-Latitude Coral Reef
We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth) and their relationships with physical variables.
This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.
3. Variable Responses of Benthic Communities to Anomalously Warm Sea Temperatures on a High-Latitude Coral Reef
Here, we use an autonomous underwater vehicle to conduct repeated surveys of three 625 m2 plots on a coral-dominated high-latitude reef in the Houtman Abrolhos Islands, Western Australia, over a four-year period spanning a large-magnitude thermal anomaly.
4. Filling the gaps: Predicting the distribution of temperate reef biota using high resolution biological and acoustic data’
Here we use cutting-edge tools (Autonomous Underwater Vehicles and ship-borne acoustics) and analytical approaches (predictive modelling) to quantify and map these highly productive ecosystems.
5. Assessing size, abundance and habitat preferences of the Ocean Perch Helicolenus percoides using a AUV-borne stereo camera system
This study successfully used an Autonomous Underwater Vehicle (AUV) and image-yielding methods to estimate size, abundance and habitat preference of an abundant and commercially important ‘rockfish’ – the Ocean Perch (Helicolenus percoides) – in rocky habitats on the continental shelf off Tasmania, SE Australia.
6. Colour-Consistent Structure-from-Motion Models using Underwater Imagery
We have been developing and validating automated approaches to correcting for colour inconsistency in underwater images collected from multiple perspectives during the construction of 3D structure-from-motion models.
7. The annual surveys by the IMOS Autonomous Underwater Vehicle (AUV) of the benthic ecosystem at the Abrolhos Islands
These surveys captured and documented the effect of the 2010-2011 ‘marine heat wave’ on the west coast. Interestingly, whilst researchers found the initial devastation to the coral reefs was large, regrowth was surprisingly fast and widespread. Although the original plate corals have not recovered, other coral species have regenerated in their place, with approximately 50% of the lost area being replaced.